[Federal Register Volume 64, Number 164 (Wednesday, August 25, 1999)]
[Proposed Rules]
[Pages 46476-46539]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-20753]
[[Page 46475]]
_______________________________________________________________________
Part II
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 148, 261, 264, 265, 268, 271, and 302
Hazardous Waste Management System; Identification and Listing of
Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land
Disposal Restrictions for Newly Identified Wastes; and CERCLA Hazardous
Substance Designation and Reportable Quantities; Proposed Rule
Federal Register / Vol. 64, No. 164 / Wednesday, August 25, 1999 /
Proposed Rules
[[Page 46476]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 148, 261, 264, 265, 268, 271, and 302
[SWH-FRL-6413-4]
RIN 2050-AD85
Hazardous Waste Management System; Identification and Listing of
Hazardous Waste; Chlorinated Aliphatics Production Wastes; Land
Disposal Restrictions for Newly Identified Wastes; and CERCLA Hazardous
Substance Designation and Reportable Quantities
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The EPA is proposing to list three of six wastes from the
chlorinated aliphatics industry as hazardous wastes under the Resource
Conservation and Recovery Act (RCRA), which directs EPA to determine
whether certain wastes from the chlorinated aliphatics industry present
a hazard to human health or the environment. The effect of listing
these three wastes will be to subject them to stringent management and
treatment standards under RCRA and to subject them to emergency
notification requirements for releases of hazardous substances to the
environment. EPA is proposing a contingent-management listing approach
for one of these wastes, and as one of two options for another of these
wastes, such that waste generators will have the option of their waste
not being listed if it is sent to a specific type of management
facility.
DATES: EPA will accept public comments on this proposed rule until
November 23, 1999. Comments postmarked after this date will be marked
``late'' and may not be considered. Any person may request a public
hearing on this proposal by filing a request by September 8, 1999.
ADDRESSES: If you wish to comment on this proposed rule, you must send
an original and two copies of the comments referencing docket number F-
1999-CALP-FFFFF to: RCRA Docket Information Center, Office of Solid
Waste (5305G), U.S. Environmental Protection Agency Headquarters (EPA,
HQ), 401 M Street, SW, Washington, D.C. 20460. Hand deliveries of
comments should be made to the Arlington, VA, address listed in the
fourth paragraph of SUPPLEMENTARY INFORMATION. You also may submit
comments electronically by sending electronic mail through the Internet
to: rcradocket@epamail.epa.gov. See the beginning of SUPPLEMENTARY
INFORMATION for instructions on electronic submission.
You should not submit electronically any confidential business
information (CBI). You must submit an original and two copies of CBI
under separate cover to: RCRA CBI Document Control Officer, Office of
Solid Waste (5305W), U.S. EPA, 401 M Street, SW, Washington, D.C.
20460. See the beginning of SUPPLEMENTARY INFORMATION for information
on viewing public comments and supporting materials.
Address requests for a hearing to Mr. David Bussard at: Office of
Solid Waste, Hazardous Waste Identification Division (5304W), U.S.
Environmental Protection Agency, 401 M Street, SW, Washington, D.C.
20460, (703) 308-8880.
FOR FURTHER INFORMATION CONTACT: For general information, contact the
RCRA Hotline at (800) 424-9346 or TDD (800) 553-7672 (hearing
impaired). In the Washington, D.C., metropolitan area, call (703) 412-
9810 or TDD (703) 412-3323. For information on specific aspects of the
rule, contact Ross Elliott of the Office of Solid Waste (5304W), U.S.
Environmental Protection Agency, 401 M Street, SW, Washington, D.C.
20460. [E-mail addresses and telephone numbers:
elliott.ross@epamail.epa.gov, (703) 308-8748.]
SUPPLEMENTARY INFORMATION: You should identify comments in electronic
format with the docket number F-1999-CALP-FFFFF. You must submit all
electronic comments as an ASCII (text) file, avoiding the use of
special characters and any form of encryption. If you do not submit
comments electronically, EPA is asking prospective commenters to
voluntarily submit one additional copy of their comments on labeled
personal computer diskettes in ASCII (text) format or a word processing
format that can be converted to ASCII (text). It is essential to
specify on the disk label the word processing software and version/
edition as well as the commenter's name. This will allow EPA to convert
the comments into one of the word processing formats utilized by the
Agency. Please use mailing envelopes designed to physically protect the
submitted diskettes. EPA emphasizes that submission of comments on
diskettes is not mandatory, nor will it result in any advantage or
disadvantage to any commenter. Supporting documents in the docket for
this Notice are also available in electronic format on the Internet.
Follow these instructions to access these documents.
WWW: http://www.epa.gov/epaoswer/hazwaste/id
FTP: ftp.epa/gov
Login: anonymous
Password: your Internet address
Files are located in /pub/gopher/OSWRCRA.
EPA will keep the official record for this action in paper form.
Accordingly, we will transfer all comments received electronically into
paper form and place them in the official record, which will also
include all comments submitted directly in writing. The official record
is the paper record maintained at the address in ADDRESSES at the
beginning of this document.
EPA responses to comments, whether the comments are written or
electronic, will be in a notice in the Federal Register or in a
response to comments document placed in the official record for this
rulemaking. We will not immediately reply to commenters electronically
other than to seek clarification of electronic comments that may be
garbled in transmission or during conversion to paper form, as
discussed above.
You may view public comments and supporting materials in the RCRA
Information Center (RIC), located at Crystal Gateway I, First Floor,
1235 Jefferson Davis Highway, Arlington, VA. The RIC is open from 9
a.m. to 4 p.m., Monday through Friday, excluding federal holidays. To
review docket materials, we recommend that you make an appointment by
calling (703) 603-9230. You may copy a maximum of 100 pages from any
regulatory docket at no charge. Additional copies cost $0.15/page. For
information on accessing paper and/or electronic copies of the
document, see the first paragraph of the SUPPLEMENTARY INFORMATION
section.
Customer Service
How Can I Influence EPA's Thinking on This Proposed Rule?
In developing this proposal, we tried to address the concerns of
all our stakeholders. Your comments will help us improve this rule. We
invite you to provide different views on options we propose, new
approaches we haven't considered, new data, how this rule may affect
you, or other relevant information. We welcome your views on all
aspects of this proposed rule, but we request comments in particular on
the items indicated at the end of each section. Your comments will be
most effective if you follow the suggestions below:
Explain your views as clearly as possible and provide a
summary of the reasoning you used to arrive at your
[[Page 46477]]
conclusions, as well as examples to illustrate your views, where
possible.
Provide solid technical and cost data to support your
views.
If you estimate potential costs, explain how you arrived
at your estimate.
Tell us which parts you support, as well as those with
which you disagree.
Offer specific alternatives.
Reference your comments to specific sections of the
proposal, such as the sections or page numbers of the preamble, or the
regulatory citations.
Remember that your comments must be submitted by the
deadline in this notice.
Include the name, date, and docket number with your
comments.
Contents of This Proposed Rule
The contents of the preamble to this proposed rule are listed in
the following outline:
I. Overview
A. Who Potentially Will Be Affected by This Proposed Rule?
B. Why Does This Rule Read Differently From Other Listing Rules?
C. What Are the Statutory Authorities for This Rule?
II. Background
A. Schedule Suit
B. Existing Chlorinated Aliphatics Listings
III. Today's Action
A. Summary of Today's Action
1. Scope of the Listing Determination
2. Summary of the Proposed Listing Determinations
3. Summary of the Remainder of This Preamble
B. Description of the Industry
C. Overview of EPA's Information Collection Activities
1. Field Investigations and Sampling
2. RCRA Section 3007 Survey
D. What Are the Risks Associated With Management of Wastewaters and
Wastewater Treatment Sludges From the Production of Chlorinated
Aliphatic Chemicals?
1. What Are the Risks for Potential Human Receptors?
2. What Are the Potential Risks for Ecological Receptors?
3. Did EPA Conduct a Peer Review of the Risk Assessment?
E. Waste-Specific Listing Determination Rationales
1. Chlorinated Aliphatics Wastewaters
2. EDC/VCM Wastewater Treatment Sludges
3. VCM-A Wastewater Treatment Sludges
4. Methyl Chloride Wastewater Treatment Sludges
5. Allyl Chloride Wastewater Treatment Sludges
F. Constituents Proposed for Addition to Appendix VIII to 40 CFR
Part 261
IV. Economic Analysis
A. What Is the Purpose of the Economic Analysis?
B. How May the Public Participate in the Economic Analysis?
C. How Are Chlorinated Aliphatic Chemicals Used in the Economy?
D. Where Are CAHCs Manufactured in the United States?
E. Have CAHCs Been Produced Historically in Other Locations in the
United States?
F. What Are the Estimated Potential Industry Costs of This Listing?
V. Proposed Treatment Standards Under RCRA's Land Disposal Restrictions
A. What Are EPA's Land Disposal Restrictions (LDRs)?
B. How Does EPA Develop LDR Treatment Standards?
C. What Kind of Treatment Standards Are Proposed?
D. Other LDR-Related Provisions
E. What Standards Are Proposed for K173?
F. What Standards Are Proposed for K174?
G. What Standards Are Proposed for K175?
H. What Other Land Disposal Restrictions Aspects Are There to the
Proposal?
I. Is There Treatment Capacity for the Proposed Wastes?
VI. Compliance Dates
A. Notification
B. Interim Status and Permitted Facilities
VII. State Authority
A. Applicability of Rule in Authorized States
B. Effect on State Authorizations
VIII. Designation of Chlorinated Aliphatic Wastes (K173, K174 and K175)
Under the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA)
A. What Is the Relationship Between RCRA and CERCLA?
B. Is EPA Proposing To Add Chlorinated Aliphatic Wastes to CERCLA?
C. How Does EPA Determine Reportable Quantities?
D. When Do I Need to Report a Release of K173, K174 or K175 Under
CERCLA?
E. What if I Know the Concentration of the Constituents in My Waste?
F. How Did EPA Determine the RQs for K173, K174 and K175 and Their
Hazardous Constituents?
G. How Do I Report a Release?
H. What Is the Statutory Authority for This Program?
I. How Can I Influence EPA's Thinking on Regulating K173, K174 and
K175 Under CERCLA?
IX. Administrative Assessments
A. Executive Order 12866
B. Regulatory Flexibility Act
C. Paperwork Reduction Act
D. Unfunded Mandates Reform Act
E. Executive Order 12875: Enhancing the Intergovernmental
Partnership
F. Executive Order 13084: Consultation and Coordination With Indian
Tribal Governments
G. Executive Order 13045: Protection of Children From Environmental
Risks and Safety Risks
H. National Technology Transfer and Advancement Act of 1995
I. Executive Order 12898: Environmental Justice
I. Overview
A. Who Potentially Will Be Affected by This Proposed Rule?
Beginning January 1, 1999 all documents related to USEPA's
regulatory, compliance and enforcement activities including rules,
policies, interpretive guidance, and site-specific determinations with
broad application, should properly identify the regulated entities,
including descriptions that correspond to the applicable SIC codes or
NAICS codes (source: 09 October 1998 USEPA memo from Peter D.
Robertson, Acting Deputy Administrator of USEPA). Today's action, if
finalized, could potentially affect those who handle the wastes that
EPA is proposing to add to the Agency's list of hazardous wastes under
the RCRA program. This action also may affect entities that may need to
respond to releases of these wastes as CERCLA hazardous substances.
These potentially-affected entities are described in the Economics
Background Document placed in the docket in support of today's proposed
rule; a summary is shown in the table below.
Summary of Facilities Potentially Affected by the USEPA's 1999 Chlorinated Aliphatics Manufacturing Waste
Listing Proposal According to Applicable SIC and NAICS Codes
----------------------------------------------------------------------------------------------------------------
Number of
Parent U.S. Parent
Item company Industry sector name relevant company NAICS
SIC code CAHC mfg. code
facilities* equivalent**
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1............................. 1311 Mining: Crude petroleum and natural 3 211111
gas.
2............................. 1400 Mining: Nonmetallic minerals, except 2 212300
fuels.
[[Page 46478]]
3............................. 2295 Manufacturing: Coated fabrics, not 1 31332
rubberized.
4............................. 2800 Manufacturing: Chemicals & allied 3 325000
products.
5............................. 2810 Manufacturing: Chemicals & allied 1 325000
products.
6............................. 2812 Manufacturing: Alkalies & chlorine 1 325181
manufacture.
7............................. 2821 Manufacturing: Plastics materials & 8 325211
resins.
8............................. 2851 Manufacturing: Paints & allied 1 32551
products.
9............................. 2869 Manufacturing: Industrial organic 1 32511
chemicals, nec.
10............................ 2911 Manufacturing: Petroleum refining..... 1 32411
11............................ 3600 Manufacturing: Electronic & other 1 335000
electric equipment.
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Total Applicable Facilities....... 23
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*The number of relevant facilities is based on the (a) type of CAHC products manufactured, (b) types of wastes
generated, and (c) baseline waste management practices, in relation to the terms and conditions of the
proposed listing options. However, all CAHC manufacturing facilities in each industrial sector code may not be
affected by the proposed listing options.
**OSW-EMRAD derived the NAICS code equivalents above from the SIC-to-NAICS conversion tables provided by the US
Department of Commerce, Bureau of the Census, at the following website: http://www.census.gov/epcd/www/
naicstab.htm. There is no direct match in the SIC-NAICS conversion tables for SIC codes 1400, 2800, 2810, and
3600, so a generalized six-digit NAICS code is provided above for these four cases.
The list of potentially affected entities in the above table may
not be exhaustive. Our aim is to provide a guide for readers regarding
entities likely to be regulated by this action. This table lists those
entities that EPA is aware potentially could be affected by this
action. However, this action may affect other entities not listed in
the table. To determine whether your facility is regulated by this
action, you should examine 40 CFR 260 and 261 carefully in concert with
the proposed rules amending RCRA that are found at the end of this
Federal Register notice. If you have questions regarding the
applicability of this action to a particular entity, consult the person
listed in the preceding section entitled FOR FURTHER INFORMATION
CONTACT.
B. Why Does This Rule Read Differently From Other Listing Rules?
Today's proposed listing determination preamble and regulations are
written in ``readable regulations'' format. The authors tried to use
active rather than passive voice, plain language, a question-and-answer
format, the pronouns ``we'' for EPA and ``you'' for the owner/
generator, and other techniques to make the information in today's rule
easier to read and understand. This new format is part of the Agency's
efforts at regulatory reinvention, and it makes today's rule read
differently from other listing rules. The Agency believes that this new
format will increase readers' abilities to understand the regulations,
which should then increase compliance, make enforcement easier, and
foster better relationships between EPA and the regulated community.
C. What Are the Statutory Authorities for This Rule?
These regulations are being proposed under the authority of
Sections 2002(a), 3001(b), 3001(e)(2) and 3007(a) of the Solid Waste
Disposal Act, 42 U.S.C. 6912(a), 6921(b) and (e)(2), and 6927(a) as
amended several times, most importantly by the Hazardous and Solid
Waste Amendments of 1984 (HSWA). These statutes commonly are referred
to as the Resource Conservation and Recovery Act (RCRA), and are
codified at Volume 42 of the United States Code (U.S.C.), Sections 6901
to 6992(k) (42 U.S.C. 6901-6992(k)).
Section 102(a) of the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), 42 U.S.C. 9602(a) is
the authority under which the CERCLA aspects of this rule are being
proposed.
II. Background
A. Schedule Suit
In 1989, the Environmental Defense Fund (EDF) sued the
Environmental Protection Agency (EPA), in part for failing to meet the
statutory deadlines of Section 3001(e)(2) of RCRA (EDF vs. Browner;
Civ. No. 89-0598 D.D.C.). To resolve most of the issues in the case,
EDF and EPA entered into a consent decree, which has been amended
several times to revise dates. The consent decree sets out deadlines
for promulgating certain RCRA rules and for completing certain studies
and reports. Paragraph 1. m. of the consent decree obliges EPA to
propose a hazardous waste listing determination for wastewaters and
wastewater treatment sludges generated from the production of specified
chlorinated aliphatic chemicals. The wastewater and wastewater
treatment sludges subject to the consent decree are those from the
production of chlorinated aliphatics for which other process wastes
already have been designated as hazardous waste F024 in 40 CFR 261.31.
According to the consent decree, EPA must propose listing
determinations by July 30, 1999 and promulgate final listing
determinations on or before September 30, 2000. Today EPA is proposing
listing determinations for these wastes in accordance with the consent
decree.
B. Existing Chlorinated Aliphatics Listings
Today's proposal does not affect the scope of the chlorinated
aliphatics process wastes that already have been listed as hazardous in
prior EPA rulemakings. These wastes include wastes designated as
hazardous waste code F024 as well as a number of other chlorinated
aliphatic wastes listed below in Table II-1. EPA is not soliciting
comment on these existing hazardous waste listings and does not intend
to respond to such comments, if received.
Likewise, EPA is not soliciting comments in today's rule on the
applicability of the existing chlorinated aliphatics listings to the
provisions of CERCLA. Wastes listed as hazardous
[[Page 46479]]
under RCRA are by definition hazardous substances under CERCLA, and are
included in the list of hazardous substances in 40 CFR 302.4, along
with their corresponding reportable quantities (``RQs''). Hazardous
substance RQs are those quantities of the designated chemical or waste
that trigger certain reporting requirements if released to the
environment. The previously listed hazardous wastes from chlorinated
aliphatics production and their corresponding RQs are listed below in
Table II-1.
Table II-1.--List of Currently-Regulated Chlorinated Aliphatic Process
Wastes and Corresponding Reportable Quantities as CERCLA Hazardous
Substances
------------------------------------------------------------------------
Hazardous substance RQ pounds (KG)
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F024--Process wastes, including but not limited to, 1 (0.454)
distillation residues, heavy ends, tars, and reactor
cleanout wastes from the production of certain
chlorinated aliphatic hydrocarbons, by free radical
catalyzed processes. These chlorinated aliphatic
hydrocarbons are those having carbon chain lengths
ranging from one to and including five, with varying
amounts and positions of chlorine substitution. [This
listing does not include wastewaters, wastewater
treatment sludges, spent catalysts, and wastes listed
in 40 CFR 261.31 or 261.32.]...........................
F025--Condensed light ends, spent filters and filter 1 (0.454)
aids, and spent dessicant wastes from the production of
certain chlorinated aliphatic hydrocarbons, by free
radical catalyzed processes. These chlorinated
aliphatic hydrocarbons are those having carbon chain
lengths ranging from one to and including five, with
varying amounts and positions of chlorine substitution.
K016--Heavy ends or distillation residues from the 1 (0.454)
production of carbon tetrachloride.....................
K018--Heavy ends from the fractionation column in ethyl 1 (0.454)
chloride production....................................
K019--Heavy ends from the distillation of ethylene 1 (0.454)
dichloride in ethylene dichloride production...........
K020--Heavy ends from the distillation of vinyl chloride 1 (0.454)
in vinyl chloride monomer production...................
K028--Spent catalyst from the hydrochlorinator reactor 1 (0.454)
in the production of 1,1,1-trichloroethane.............
K029--Waste from the product steam stripper in the 1 (0.454)
production of 1,1,1-trichloroethane....................
K030--Column bottoms or heavy ends from the combined 1 (0.454)
production of trichloroethylene and perchloroethylene..
K095--Distillation bottoms from the production of 1,1,1- 1 (0.454)
trichloroethane........................................
K096--Heavy ends from the heavy ends column from the 1 (0.454)
production of 1,1,1-trichloroethane....................
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III. Today's Action
A. Summary of Today's Action
1. Scope of the Listing Determination
Aliphatic hydrocarbons are compounds composed of the atoms of
hydrogen and carbon, where the carbon atoms are linked by covalent
bonds in an open-chain (straight and branched) structure, and those
cyclic compounds that resemble the open-chain compounds. Aliphatics are
distinguished from aromatic hydrocarbons, which are defined as benzene
and compounds that resemble benzene in chemical behavior. For an
aliphatic to be chlorinated, one or more hydrogen atoms have been
chemically replaced with chlorine atoms. The chlorinated aliphatic
chemicals, the wastes of which are described in the (existing) F024
listing description, and identified in the consent decree, are those
produced by free-radical catalyzed processes with carbon chain lengths
ranging from one to five.
EPA performed an initial review and investigation of the waste
categories identified in the consent decree, as well as a review of
chlorinated aliphatics production processes and the wastewaters and
wastewater treatment sludges generated by these processes. The Agency
decided, for the purpose of studying chlorinated aliphatic wastes, to
divide the wastestreams into several distinct waste groupings. Waste
groupings were defined to differentiate between unique residuals, as
well as to differentiate between unique management practices (e.g., on-
site land treatment) and/or particular constituents (e.g., mercury).
The Agency segregated chlorinated aliphatics wastewaters into two
groupings, with one group being wastewaters generated from the
production of vinyl chloride monomer using mercuric chloride catalyst
in an acetylene-based process. These wastewaters were evaluated as one
group due to the unique nature of this production process, the fact
that these wastewaters are treated in a dedicated wastewater treatment
system, and the presence of mercury in the wastestream. All other
chlorinated aliphatic wastewaters were included in a second group and
evaluated collectively. The Agency found that many producers of
chlorinated aliphatics manufacture several different chlorinated
aliphatic products at a single facility and commingle the wastewaters
generated by all processes prior to treatment in a single wastewater
treatment system.
The Agency identified four waste groupings for wastewater treatment
sludges generated by the chlorinated aliphatics industry. These waste
groupings were defined based primarily upon the particular management
practices used to manage the wastes, but also based on particular
production processes. The Agency identified four waste groups for
chlorinated aliphatics wastewater treatment sludges. These waste groups
include sludges generated from the treatment of wastewaters from the
production of:
Ethylene dichloride and/or vinyl chloride monomer (EDC/
VCM);
Vinyl chloride monomer using mercuric chloride catalyst in
an acetylene-based process (VCM-A);
Methyl chloride; and
allyl chloride.
The scope of today's notice does not include any other process
residuals generated by the chlorinated aliphatics industry. In
particular, the Agency is not re-evaluating previous listing
determinations concerning wastes generated by chlorinated aliphatics
production processes.
The Agency also points out that the consent decree specifies that
this listing determination ``shall include wastewaters and wastewater
treatment sludges generated from the production of chlorinated
aliphatics specified in the F024 listing'' (a listing which is limited
to wastes from chlorinated aliphatic production using the ``free
radical catalyzed process'' but does not include wastewaters or
wastewater treatment sludges). However, for today's proposed rule the
Agency did not restrict its evaluation of wastewaters and wastewater
treatment sludges to only those generated from chlorinated aliphatics
manufacturers using the free radical catalyzed process. In the
rulemaking for the F024 listing (which includes process wastes such as
distillation residues, heavy ends, and tars, but not wastewaters and
[[Page 46480]]
wastewater treatment sludges) we found that there were distinct
differences in the amount and type of chemical constituents present in
these production wastes as a direct result of the production process
used. For example, the free radical catalyzed reactions tended to
produce unwanted organic compounds, as well as the desired chemical
product, because this type of reaction is less specific (in terms of
desired product) than other types of processes used. As a result, the
chemical constituents that were the basis for listing F024 includes
many organic compounds that are more prevalent in process wastes
(again, tars, heavy ends, etc.) generated from the free radical
catalyzed process.
However, in developing the information for today's proposed
listing, EPA was concerned that limiting the scope of the investigation
to free radical catalyzed processes might not be appropriate because of
the different nature of wastewaters and wastewater treatment sludges as
compared with the F024 process wastes. Wastewaters may be generated in
different ways, including from scrubber waters, cooling waters, as well
as reaction media, etc. Ultimately, our primary reason for not
restricting our evaluation of wastewaters and wastewater treatment
sludges to those generated by free radical catalyzed processes is that
our preliminary analysis of these wastes indicated that the
constituents of concern (i.e., dioxins, chloroform, arsenic) were not
the same as the constituents of concern associated with the previously-
listed F024 and F025 wastes. In those previous listing determinations
(which did not include wastewaters or wastewater treatment sludges) the
Agency was able to distinguish risk levels of concern based upon
particular production processes.
In the case of today's proposed listing determination, we were not
able to make such a distinction. The primary constituents of concern in
the wastes we are proposing to list as hazardous in today's notice are
dioxins, whereas dioxins were not a basis for listing the F024 and F025
wastes. Data currently available to the Agency does not support a
conclusion that wastewaters and wastewater treatment sludges generated
by free radical catalyzed processes have significantly different
concentrations of dioxins than other types of production processes used
to manufacture chlorinated aliphatics. However, EPA requests comment
and data addressing the issue of whether one type of manufacturing
process (e.g., free radical catalyzation) versus all other potential
processes (e.g., ionic catalyzed processes) would result in different
levels of dioxins in the resulting wastestream. The Agency will
consider modifying the listing description proposed in today's
rulemaking as appropriate to account for distinctions identified in
information available to EPA at the time of the final rule.
2. Summary of the Proposed Listing Determinations
In today's notice, EPA is proposing to add three wastes generated
by the chlorinated aliphatics industry to the list of hazardous wastes
in 40 CFR 261.32. Below are the wastestreams EPA is proposing to list
as hazardous with their corresponding proposed EPA Hazardous Waste
Numbers.
K173 Wastewaters from the production of chlorinated aliphatic
hydrocarbons, except for wastewaters generated from the production
of vinyl chloride monomer using mercuric chloride catalyst in an
acetylene-based process. This listing includes wastewaters from the
production of chlorinated aliphatic hydrocarbons that have carbon
chain lengths ranging from one to, and including five, with varying
amounts and positions of chlorine substitution.
K174 Wastewater treatment sludges from the production of ethylene
dichloride or vinyl chloride monomer (EDC/VCM).
K175 Wastewater treatment sludges from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-
based process.
EPA is proposing to list these wastes because these residuals meet
the criteria set out in 40 CFR 261.11(a)(3) for listing a waste as
hazardous. EPA assessed and considered these criteria for all six
wastestreams through the use of risk assessments and risk modeling, as
well as a consideration of other pertinent factors. Today's proposed
listing determination follows the elements of the Agency's listing
decision policy that was presented in the proposed listing for wastes
generated by the dye and pigment industries published in the Federal
Register on December 22, 1994 (see 59 FR 66073). This policy uses a
``weight-of-evidence'' approach in which calculated risk information is
a key factor considered in making a listing determination.
Upon promulgation of these proposed listings, wastes meeting the
listing descriptions will become hazardous wastes and need to be
managed in accordance with RCRA subtitle C requirements. Residuals from
the treatment, storage, or disposal of the wastewater treatment sludges
proposed to be listed as hazardous also will be classified as hazardous
wastes pursuant to the ``derived-from'' rule (40 CFR 261.3(c)(2)(i)).
1 Also, with certain limited exceptions, any mixture of a
listed hazardous waste and a solid waste is itself a RCRA hazardous
waste (40 CFR 261.3(a)(2)(iv), ``the mixture rule'').
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\1\ As explained later in this notice, residuals generated from
the management of wastewaters proposed to be listed as hazardous
(i.e., wastewater treatment sludges) will not be subject to the
derived-from rule due to the fact that EPA conducted separate
investigations of these residuals and they are the subject of
independent listing determinations.
---------------------------------------------------------------------------
In today's notice, the Agency is proposing an alternative approach
to listing two of the wastes from chlorinated aliphatics processes as
hazardous, rather than proposing to list these wastes in accordance
with the Agency's traditional listing approach. The Agency is proposing
a conditional listing approach for one waste, and as one of two
alternative approaches for a second waste, because the Agency has
evaluated the ways in which the wastes are likely to be managed and has
determined that certain waste management activities would present
significant risks but that others would be protective of human health
and the environment. Under a contingent management approach, EPA is
proposing to list particular wastes as hazardous only if the wastes are
managed in a way other than the manner in which the Agency has
determined is protective of human health and the environment. In
implementing a conditional-listing approach, the Agency is proposing
that wastes that fall outside the scope of the listing description
(e.g., are destined for the appropriate type of disposal) are non-
hazardous when generated. However, if it turns out that the waste
actually is not handled in accordance with the conditions of the
listing at any point in its management, the generators or other
handlers of the waste would be subject to various enforcement actions
or, depending on the violations, the waste could become a hazardous
waste and may even be considered hazardous from the point of
generation. The Agency's proposed conditional-listing approach for
wastes generated from chlorinated aliphatics processes is further
discussed in section III.E of today's notice.
Today's action also proposes not to list as hazardous the following
three wastes:
Process wastewaters from the production of vinyl chloride
monomer using mercuric chloride catalyst in an acetylene-based process,
Wastewater treatment sludges from the production of methyl
chloride, and
[[Page 46481]]
Wastewater treatment sludges from the production of allyl
chloride.
3. Summary of the Remainder of this Preamble
Section III.B. describes the chlorinated aliphatics industry.
Section III.C. describes how the information was gathered in support of
today's proposed rule. Section III.D. is a description of the risk
assessment performed for three of the wastes evaluated in today's rule,
including chlorinated aliphatic wastewaters, EDC/VCM sludges, and
methyl chloride sludges, and the results of these assessments. Section
III.E provides the rationale for the proposed listing decisions for all
six wastes analyzed in today's rule. Because full risk analyses were
not necessary for VCM-A wastewaters, VCM-A wastewater treatment
sludges, or allyl chloride sludges, we discuss our assessment of risks
attributable to each of these wastes in the same sections where we
describe our listing decisions for the wastes. Section IV contains the
economic assessment of the industry and the estimated impact of today's
proposed listing determinations. Section V describes the proposed land
disposal restriction requirements for those wastes we propose to list
as hazardous, along with determinations of whether there is adequate
treatment and disposal capacity for these wastes. Sections VI
(compliance dates), VII (state authority), VIII (designating CERCLA
hazardous substances) and IX (administrative assessments) discuss other
analyses required by statute and various executive orders.
B. Description of the Industry
In 1992, when EPA began gathering information about the U.S.
chlorinated aliphatics industry, it consisted of 27 facilities owned by
20 corporations. However, as a result of information updates in 1997,
we determined that two chlorinated aliphatics facilities had closed and
two additional facilities manufacture de minimis quantities of
chlorinated aliphatics, lowering the number of facilities affected by
today's proposed rulemaking to 23 and corporations to 19.
Chlorinated aliphatics production facilities are located primarily
in and around the petroleum/petrochemical industry which generally is
located along the Gulf Coast. The majority of facility locations are
fully integrated petrochemical processing facilities. A few facilities
are co-located with other chemical manufacturing and/or petroleum
refining facilities. These integrated facilities often manage wastes
generated across different production processes within the same waste
management systems. For example, these facilities often combine
chlorinated aliphatic wastewaters with non-chlorinated aliphatics
wastewaters prior to treatment. The combined wastewater treatment
system generates a commingled sludge. In addition, there are facilities
that manage chlorinated aliphatics wastewaters in separate or dedicated
wastewater treatment systems. For the purpose of this listing
determination, the Agency refers to these treatment systems, and
resulting sludges, as ``dedicated'' systems and ``dedicated'' sludges.
Nearly 10 million metric tons of chlorinated aliphatics were
produced in 1996. More than 85 percent of the chlorinated aliphatic
products manufactured in 1996 was ethylene dichloride and vinyl
chloride monomer (EDC/VCM) manufactured via the ``balanced process.''
This process involves the production of EDC as an intermediate product
using direct chlorination and oxyhydrochlorination of ethylene,
followed by cracking to produce VCM. Other chlorinated aliphatics
production includes chlorinated methanes, methyl chloride, and a
variety of other products.
C. Overview of EPA's Information Collection Activities
EPA's investigation of the wastes generated by the chlorinated
aliphatics industry can be characterized in terms of two major
information collection efforts: field investigations and survey
evaluation. The Agency's field investigations included engineering site
visits, ``familiarization sampling'' (sample collection and analysis to
gain a preliminary understanding of the nature and concentration of
potential constituents of concern), and ``record sampling'' (sample
collection and analysis to provide data to use in assessing the
potential risks posed by the wastes). The survey effort included the
development, distribution, and assessment of an extensive industry-wide
RCRA Section 3007 survey. Each of these efforts is summarized below.
1. Field Investigations and Sampling
EPA initiated its work activities with a series of engineering site
visits. The primary purpose of the site visits was to gather
information on chlorinated aliphatic manufacturing processes and the
generation, management, and characterization of the consent decree
wastes. In addition, the field teams identified potential record
sampling locations. The Agency conducted site visits at 16 facilities
prior to record sampling; site visit facilities were selected based on
a goal of obtaining first hand information from a representative
sampling of all chlorinated aliphatic manufacturers as well as all
relevant manufacturing and waste management processes, including an
investigation of dedicated wastewater treatment units.
Concurrently, the Agency initiated the analytical phase of this
listing determination with the development of a Quality Assurance
Project Plan (QAPjP) for sampling and analysis, followed by collection
of 15 familiarization samples from three different manufacturing
facilities (collected during the engineering site visits). The purpose
of collecting familiarization samples is to assess the effectiveness of
the analytical methods identified in the QAPjP for the analysis of the
residuals of concern.
Upon successful completion of the familiarization sampling and
analysis effort, the Agency initiated record sampling and analysis of
the consent decree wastes. The Agency sampled wastewaters and
wastewater treatment sludges from twelve facilities. During a four-
month period beginning in April of 1997, the Agency collected 52
samples, excluding additional blanks and matrix spike/matrix spike
duplicates(MS/MSD) collected for quality assurance purposes. Of these
52 samples, 41 were wastewater samples, and 11 were wastewater
treatment sludge samples.
2. RCRA Section 3007 Survey
EPA developed an extensive questionnaire under the authority of
Section 3007 of RCRA for distribution to the chlorinated aliphatics
manufacturing industry. The purpose of the survey was to gather
information about solid and hazardous waste generation and management
practices in the U.S. chlorinated aliphatics manufacturing industry
necessary to support the listing determination. The questionnaire
covered topics such as chlorinated aliphatic product information,
facility and unit process flow diagrams, process descriptions, residual
generation and residual management profiles.
The Agency distributed the survey in November of 1992 to 57
facilities and/or corporations identified as potential chlorinated
aliphatics manufacturers from the most recent information available at
the time. Of the 57 surveys distributed, completed surveys were
received from 27 facilities. These facilities represent 20 companies
that reported that they had manufactured chlorinated aliphatics in
1991. The remaining facilities notified EPA that they had either
stopped operations or
[[Page 46482]]
did not manufacture chlorinated aliphatic products.
We also conducted an exhaustive engineering review of the submitted
surveys for accuracy and completeness. Data from the survey responses
was then entered into a data base known as the Chlorinated Aliphatics
Industry Studies Data Base (ISDB). We conducted quality assurance
reviews of the ISDB to identify any inappropriate entries and missing
data links. The exhaustive engineering review of each facility's
response resulted in follow-up letters and/or telephone calls to
facility representatives seeking clarifications, corrections, and
additional data where needed. The responses to these requests for
clarification, along with additional information gathered during
engineering site visits and familiarization and record sampling
activities were entered into the data base.
In 1996 we conducted a review of data collected previously, and re-
contacted facility representatives to verify the status of chlorinated
aliphatics manufacturing operations. In June of 1997, the Agency sent
requests for updated data (for calendar year 1996) regarding consent
decree wastes generated to each facility. We processed the data
received from this request in the same manner as the original RCRA
surveys, and entered the new information into the ISDB. Between 1993
and 1996, two chlorinated aliphatics manufacturers ceased operations,
resulting in a universe of 23 chlorinated aliphatics manufacturing
facilities owned and operated by 19 different companies. Each of the 23
current manufacturers of chlorinated aliphatics generate at least one
wastestream identified in the consent decree. All 23 facilities
generate at least one wastewater residual, while 14 facilities reported
that they generate wastewater treatment sludges.
D. What Are the Risks Associated With Management of Wastewaters and
Wastewater Treatment Sludges From the Production of Chlorinated
Aliphatic Chemicals?
As discussed in Section III.A.2. of this preamble, EPA considers
the Listing criteria set out in 40 CFR 261.11, as well as any other
information relevant to the criteria, in making listing determinations.
The criteria provided in 40 CFR 261.11 include eleven factors for
determining ``substantial present or potential hazard to human health
and the environment.'' Nine of these factors, as described generally
below, are directly incorporated into EPA's completion of a risk
assessment for the wastestreams of concern:
Toxicity (Sec. 261.11(a)(3)(i)) is considered in
developing the health benchmarks used in the risk assessment modeling.
Constituent concentrations and waste quantities
(Sec. Sec. 261.11(a)(3)(ii) and 261.11(a)(3)(viii)) are used to define
the initial conditions for the risk evaluation.
Potential to migrate, persistence, degradation, and
bioaccumulation of the hazardous constituents and any degradation
products (261.11(a)(3)(iii), 261.11(a)(3)(iv), 261.11(a)(3)(v), and
261.11(a)(3)(vi)) are all considered in the design of the fate and
transport models used to determine the concentrations of the
contaminants to which individuals are exposed.
We consider two of the remaining factors, plausible mismanagement
and other regulatory actions (Sec. Sec. 261.11(a)(3)(vii) and
261.11(a)(3)(x)) in establishing the waste management scenario(s)
modeled in the risk assessment.
EPA conducted analyses of the risks posed by wastewaters and
wastewater treatment sludges from the production of chlorinated
aliphatic chemicals to assist in the determination of whether the
wastes meet the criteria for listing set forth in 40 CFR 261.11(a)(3).
This section (III.D.) discusses the human health risk analyses and
ecological risk screening analyses EPA conducted to support our
proposed listing determinations for chlorinated aliphatics wastewaters
(other than VCM-A wastewaters), EDC/VCM wastewater treatment sludges,
and methyl chloride wastewater treatment sludges. We consider the risk
analyses in developing our listing decisions for each of the
wastestreams (described in Sections III.E.1.a. for chlorinated
aliphatics wastewaters, III.E.2. for EDC/VCM sludges, and III.E.4. for
methyl chloride sludges). The risk analyses we describe in this section
(III.D.) are presented in detail in the Risk Assessment Technical
Background Document for the Chlorinated Aliphatics Listing
Determination which is located in the docket for today's proposed rule.
Because full risk analyses were not necessary for VCM-A
wastewaters, VCM-A sludges, or allyl chloride sludges, we discuss our
assessment of risks attributable to each of these wastes in the same
sections where we describe our listing decisions for each of the
wastes, that is, Sections III.E.1.b., III.E.3, III.E.5, respectively.
1. What are the Risks for Potential Human Receptors?
a. What was EPA's Approach to Conducting the Human Health Risk
Assessment?
EPA's human health risk analyses for chlorinated aliphatics
wastewaters and EDC/VCM and methyl chloride sludges provide estimates
of the incremental human health risks resulting from exposure to
contaminants detected in these wastes. The incremental human health
risks are expressed as estimates of excess lifetime cancer risk for
individuals (``receptors'') who may be exposed to carcinogenic (cancer-
causing) contaminants and hazard quotients (HQs) for those contaminants
that produce noncancer health effects. Excess lifetime cancer risk is
the incremental probability (chance) of an individual developing cancer
over a lifetime as a result of exposure to a carcinogen. A hazard
quotient is the ratio of an individual's chronic daily dose of a
noncarcinogen to an acceptable daily dose for chronic exposures to the
noncarcinogen.
EPA used two different methods of analysis to estimate risks. These
methods are called ``deterministic risk analysis'' and ``probabilistic
risk analysis.'' A deterministic risk analysis produces a point
estimate of risk or hazard for each receptor based on using a single
value for each parameter in the analysis. A probabilistic analysis
calculates risk or hazard by allowing some of the parameters to have
more than one value, consequently producing a distribution of risk or
hazard for each receptor. A parameter is any one of a number of inputs
or variables (such as waste volume or distance between the waste
management unit and the receptor) required for the fate and transport
and exposure models and equations that EPA uses to assess risk. (In
some cases EPA treats multiple parameters as a single parameter for the
purpose of conducting our analyses. We do this to prevent inadvertently
combining parameters in our analyses in ways that are unrealistic. For
example, EPA treats environmental setting [location] parameters such as
climate, depth to groundwater, aquifer type as a single set of
parameters. We believe that, for example, allowing the climate from one
location to be paired with the depth to groundwater for another
location could result in a scenario that would not occur in nature.)
EPA conducts both ``central tendency'' and ``high end''
deterministic risk assessments to attempt to quantify the cancer risk
or non-cancer hazard for the ``average'' receptor in the population
[[Page 46483]]
(the central tendency risk) and the risk or hazard for individuals in
small, but definable ``high end'' segments of the population (the high
end risk). For central tendency deterministic risk analyses, we set all
parameters at their central tendency values. For the chlorinated
aliphatics risk assessments, the central tendency values generally are
either mean (average) or 50th percentile (median) values.
We use high end deterministic risk analysis to predict the risks
and hazards for those individuals exposed at the upper range of the
distribution of exposures. EPA's Guidance For Risk Characterization
(EPA 1995) 2 advises that ``conceptually, high end exposure
means exposure above about the 90th percentile of the population
distribution, but not higher than the individual in the population who
has the highest exposure,'' and recommends that ``* * * the assessor
should approach estimating high end by identifying the most sensitive
variables and using high end values for a subset of these variables,
leaving others at their central values.'' For the chlorinated
aliphatics high end deterministic risk analyses, EPA set two parameters
at their high end values (generally 90th percentile values), and set
all other parameters at their central tendency values. We used a
``sensitivity analysis'' to identify the two parameters that we set at
high end. A sensitivity analysis is an iterative procedure in which an
analysis is performed by alternately setting different parameters at
high end to identify the parameters that most influence the analysis'
outcome. EPA compares the different results generated by the
sensitivity analysis and selects the two high end parameters to which
the analysis was ``most sensitive,'' that is, the two parameters that
are expected to generate the greatest estimate of risk or hazard.
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\2\ EPA. 1995. Guidance for Risk Characterization. U.S.
Environmental Protection Agency Science Policy Council. February.
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EPA used probabilistic risk assessment to support the results of
the deterministic risk analyses and to allow EPA to quantify individual
risk at selected percentiles of the risk distribution (for example,
50th percentile, 90th percentile, 95th percentile). EPA conducted
probabilistic risk analyses for those combinations of receptor,
contaminant, and pathway for which risk or hazard estimated using a
deterministic analysis exceeded the following criteria: a cancer risk
of 1 x 10 -6 or a hazard quotient of 1. In a probabilistic
analysis, each parameter may have more than one value. EPA develops
``probability density functions'' (PDFs), distributions that describe
the full range of values that the various input parameters may have.
Some of the parameters in the probabilistic analysis are set as
constant values because (1) there are insufficient data to develop a
PDF; (2) EPA made assumptions to simplify the analysis in cases where
such simplifications would improve the efficiency of the analysis
without significantly affecting the results; (3) site-specific
constants are available; or (4) the analysis has not been shown to be
sensitive to the value of the parameter, that is, even if the parameter
varies, the resulting risk estimate does not vary significantly. The
Risk Assessment Technical Background Document for the Chlorinated
Aliphatics Listing Determination describes the input parameters used in
the probabilistic analysis. In the probabilistic analysis, risk is
approximated through repetitive calculation of the fate and transport
and exposure equations and models using input parameters randomly
selected from the PDFs. The result of the probabilistic analysis is a
distribution of the risks or hazards for each of the receptors.
The human health risk assessments that EPA conducted to support the
chlorinated aliphatics listing determination included four primary
tasks: (1) establishing that there are constituents in the wastes that
are of concern to the Agency and that warrant analysis to determine
their risk to human health; (2) establishing a scenario under which
contaminants are released from a waste management unit and subsequently
are transported in the environment to a human receptor; (3) estimating
the concentrations of contaminants to which the receptor might be
exposed; (4) quantifying the receptor's exposure to contaminants and
the contaminants' toxicity to the receptor; and (5) describing the
receptor's predicted risk. The following sections discuss how EPA
completed each of these tasks for the risk assessments conducted to
support the chlorinated aliphatics listing determination.
b. How Did EPA Determine Which Waste Constituents and Waste Volumes
Would Be Evaluated in the Risk Assessments?
To support the chlorinated aliphatics listing determination, EPA
collected and analyzed samples of wastewaters from the production of
chlorinated aliphatic chemicals, wastewater treatment sludges from the
production of EDC/VCM, and wastewater treatment sludges from the
production of methyl chloride (see Section III.E of today's preamble,
as well as the Background Document for Identification and Listing of
Chlorinated Aliphatics Production Wastes, for further discussion of
EPA's waste characterization efforts). We used the results of these
waste analyses to establish the ``constituents of potential concern''
(COPCs) in the wastes. We derived waste volume information from data
provided by facilities in their RCRA Section 3007 questionnaire
responses.
EPA collected and analyzed 41 samples of wastewaters generated from
the production of chlorinated aliphatic chemicals. EPA collected six of
these samples at the influent (or ``headworks'') of wastewater
treatment systems that manage only wastewaters derived from the
production of chlorinated aliphatic chemicals. We call these samples
``dedicated'' chlorinated aliphatics wastewater samples,3
and we chose to use these samples in our assessment of the risks and
hazards attributable to the management of chlorinated aliphatic
wastewaters. (The assessment of dedicated sample data allows us to
evaluate without question what risks are attributable to the wastes of
concern to the Agency.) Because we used analytical data for dedicated
chlorinated aliphatics wastewater samples in our analysis, we also used
dedicated chlorinated aliphatic wastewater volumes in our analysis. We
identified eight wastewater volumes that represent the volumes of
dedicated chlorinated aliphatics wastewaters discharged to the
headworks of chlorinated aliphatics facility wastewater treatment
systems.
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\3\ ``Dedicated'' chlorinated aliphatic wastewaters are those
that are comprised only of chlorinated aliphatics process
wastewaters, that is, wastewaters generated from the production of
the chlorinated aliphatic chemicals of concern to this listing
determination.
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EPA collected and analyzed seven samples of nonhazardous EDC/VCM
sludge. (Some sludges generated by this industry already are designated
as hazardous because they include material derived from wastes that EPA
previously listed as hazardous waste.) Four were samples of sludges
that were derived from wastewater treatment systems that manage only
EDC/VCM process wastewaters. These samples are ``dedicated'' EDC/VCM
sludge samples. Three were samples of sludges that result from the
treatment of EDC/VCM process wastewaters combined with wastewaters from
non-EDC/VCM processes and sources. EPA chose to use only the dedicated
EDC/VCM sample data in our analysis. Because we used
[[Page 46484]]
analytical data for dedicated EDC/VCM sludge samples in our analysis,
we also used ``dedicated'' EDC/VCM sludge volumes. EPA divided the
volume of wastewater attributable to EDC/VCM processes by the total
volume of wastewater influent, and applied the resultant ratio to the
total sludge volumes to obtain the volume of wastewater treatment
sludge attributable to EDC/VCM processes (that is, the ``dedicated ``
EDC/VCM sludge volume).
The methyl chloride sludge, generated by only one facility, results
from treatment of the combined wastewaters from the facility's methyl
chloride production process and other facility processes and sources.
The facility reports that approximately 18 percent of the wastewater
that generates the sludge is from the methyl chloride process. The
remainder of the wastewater is from other processes. Because the
sludge, as generated, is not dedicated, and there is no means to obtain
a dedicated sample of the methyl chloride sludge, we conducted our risk
assessment using the sample data for the nondedicated methyl chloride
sludge sample, and, comparably, the nondedicated (total) methyl
chloride sludge volume.
Using the results of the analysis of the waste samples, EPA
developed a list of ``chemicals of potential concern'' (COPCs) for the
chlorinated aliphatics wastewaters, EDC/VCM sludges, and methyl
chloride sludges. The COPCs are the constituents which were the subject
of EPA's risk assessment. EPA developed the COPC lists by taking the
complete list of detected constituents in the wastes and eliminating
constituents from the list that occurred at concentrations clearly
below levels of concern, based on screening analyses developed to
maximize risk estimates. For chlorinated aliphatics wastewaters and
EDC/VCM sludges, EPA also eliminated constituents when a constituent
was detected in only one of the samples and the concentration of the
constituent in the one sample was qualified with the ``J'' qualifier,
indicating that the constituent was detected below the quantitation
limit and the reported value was estimated. Specifically, the
laboratory detected 69 constituents in chlorinated aliphatics
wastewater samples of which we eliminated 28; 53 constituents in EDC/
VCM sludges of which we eliminated 16; and 19 constituents in methyl
chloride sludges of which we eliminated 11.
Six polychlorinated dibenzodioxin (``dioxin'') congeners and ten
polychlorinated dibenzofuran (``furan'') congeners were among the
constituents detected in samples of the chlorinated aliphatics
wastewaters, EDC/VCM sludges, and methyl chloride sludges and evaluated
in the risk assessment. EPA classifies the furan congeners and certain
polychlorinated biphenyl (PCB) congeners as ``dioxin-like compounds''
because of their structural similarity to the dioxins (EPA 1994a
4). In today's preamble we use the term ``dioxins'' to
represent both the dioxin and furan congeners. Our use of the term
``dioxins'' does not refer to dioxin-like PCBs because we did not
analyze for PCBs in our waste samples from the chlorinated aliphatics
industry since we do not expect PCBs to be constituents of the
chlorinated aliphatics wastes that are the subject of today's listing
determination.
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\4\ EPA. 1994a. Estimating Exposure to Dioxin-Like Compounds,
Volume I: Executive Summary. Review Draft. EPA/600/6-88/005Ca.
Office of Research and Development. June.
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c. What Exposure Scenarios Did EPA Evaluate?
Prior to conducting the risk assessments, EPA had to establish that
there is a plausible scenario under which a receptor might be exposed
to contaminants in the wastewaters and sludges. Establishing this
scenario required that EPA determine:
How the waste is managed or is likely to be managed;
How contaminants could be released from the waste
management unit;
How contaminants could be transported in the environment
to a point of contact with a receptor; and
How a receptor could be exposed to the contaminants.
One respondent to EPA's Sec. 3007 questionnaire reported that they
discharge a portion of their nonhazardous chlorinated aliphatics
wastewaters to nonhazardous underground injection wells. Section
III.E.1.a.i. discusses EPA's evaluation of the underground injection
waste management scenario. Twenty-three respondents reported that they
manage their nonhazardous or exempt chlorinated aliphatics wastewaters
in tanks. Because management of wastewaters in tanks is the dominant
wastewater management practice in the chlorinated aliphatics industry,
EPA chose to evaluate tanks in our risk assessment for chlorinated
aliphatics wastewaters. For reasons discussed in III.E.1.a.i., EPA
chose to evaluate risks attributable to management of chlorinated
aliphatics wastewaters in uncovered aerated biological treatment tanks.
One respondent to EPA's Sec. 3007 questionnaire reported that they
manage their EDC/VCM wastewater treatment sludges in an onsite land
treatment unit. All other respondents reported that nonhazardous EDC/
VCM sludges are managed in landfills. Eight facilities send EDC/VCM
sludges to offsite nonhazardous waste landfills, two facilities manage
EDC/VCM sludge in onsite nonhazardous industrial waste landfills, and
one facility manages their nonhazardous EDC/VCM sludge in an onsite
hazardous waste landfill (see section III.E.2.a. in today's preamble
for a description of current methods for managing EDC/VCM sludges). For
this assessment, EPA evaluated the risks associated with management of
EDC/VCM sludges in unlined municipal landfills and in a land treatment
unit. Because the only facility that generates methyl chloride sludges
manages them in an onsite nonhazardous industrial waste landfill, EPA
evaluated this management scenario in our risk assessment for methyl
chloride sludges. The Risk Assessment Technical Background Document for
the Chlorinated Aliphatics Listing Determination provides a complete
discussion of the parameters that define the characteristics of the
waste management units.
EPA determined that releases from all of the waste management units
(tank, land treatment unit, and landfill) could occur through release
of vapor emissions to the air. In addition, for the land treatment unit
and the landfill, EPA determined that releases could occur through
leaching of the waste into the subsurface. We assumed that the
chlorinated aliphatics industry's tanks retain sufficient structural
integrity to prevent wastewater releases to the subsurface (and
therefore to groundwater), and that overflow and spill controls prevent
wastewater releases to the ground surface. For the land treatment unit,
releases also could occur through release of particulate emissions to
the air and runoff and erosion of waste from the unit. EPA assumed that
wastewater would entrain any particulate matter such that particulates
would not be released from the tanks. EPA did not evaluate particulate
emissions from the landfills because the moisture content of the
sludges (41 to 74 percent moisture) would prevent generation and
release of particulates to the air in the time between placement of the
waste in the landfill and application of daily cover or a new day's
waste addition. EPA also assumed that runon/runoff controls would
prevent releases from the landfills due to erosion and runoff.
EPA also evaluated the mechanisms and pathways by which
contaminants
[[Page 46485]]
might be transported to the points where receptors are exposed. The
mechanisms and pathways we evaluated are as follows:
Eroded waste can be transported by runoff and deposited
onto the soil and into surface water bodies.
Leachate can migrate through the unsaturated 5
zone to the saturated 6 zone, where contaminants are
transported in groundwater to drinking water wells and to points of
discharge to surface water bodies.
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\5\ The unsaturated (vadose) zone is a subsurface zone in which
the pore spaces contain both water and air.
\6\ The saturated zone is a subsurface zone in which all pore
spaces are full of water.
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Vapor emissions can remain dispersed in the air, or can be
deposited through wet and dry deposition. Specifically, EPA models:
The concentration of vapor phase contaminants in air,
The diffusion of vapor phase contaminants into plants,
The diffusion of vapor phase contaminants into surface
water,
Wet deposition of vapors onto soils and surface water (for
example, due to wash-out [scavenging] by precipitation).
Dry deposition of vapors onto soils (for example, due to
density).
Although we do not evaluate wet and dry deposition of
vapors onto plants, we do assume that wet and dry deposition of vapors
onto soils increase the contaminant concentrations in the soil and
result in additional uptake of contaminants into plants via soil-to-
plant uptake.
Particulate emissions can remain dispersed in the air or
be deposited through wet deposition (in precipitation) or dry
deposition (particle settling). We assume that particulates may be
deposited onto soil and surface water through both wet and dry
deposition, and onto plants through dry deposition.
Human receptors indirectly may come into contact with vapors that
diffuse into vegetation, particulates that are deposited on vegetation,
or contaminants that are taken up by vegetation from the soil through
exposure to contaminated home-grown fruits and vegetables, as well as
exposure to contaminated beef and dairy products derived from cattle
which have ingested contaminated forage, silage, grain, and surface
soil. Receptors that ingest fish also indirectly may come into contact
with contaminants in air-borne vapors and particulates (through vapor
diffusion into surface water, vapor deposition onto surface water, and
particulate deposition onto surface water), contaminated groundwater
(through groundwater discharge into surface water), and runoff and
eroded soil that enter surface water.
EPA determined that the following receptors reasonably represent
the types of individuals that could be exposed to contaminants in
chlorinated aliphatics wastes, and were the receptors evaluated in our
risk analyses:
an adult resident
the child of a resident
a home gardener
a farmer
the child of a farmer
a fisher
The following sections describe briefly EPA's primary assumptions
regarding the characteristics and activities of each of the receptor
types, and the routes by which each receptor is exposed.
Adult Resident and Child of Resident--We assume that an adult and
child reside near the waste management unit. The residential receptors
inhale vapors and particulate matter that are dispersed in the ambient
air. EPA assumes that household water is supplied to the residential
receptors by a domestic groundwater well that is located near their
home. The adult resident and child of the resident drink water that
comes from the well. We assume that the adult resident inhales vapors
that are emitted from the water that they use in their house (for
example, during showering), and that the adult resident's skin also is
exposed to groundwater when he/she bathes. The residential receptors do
not ingest foods that are grown in the vicinity of their home, however
they do incidentally ingest surface soil from their yard.
Home Gardener--We assume that the residential receptor may have a
home garden. The home gardener grows fruit, exposed vegetables
(vegetables with edible parts that are exposed at land surface), and
root vegetables. Approximately 23 percent of the exposed vegetables, 11
percent of the root vegetables, and 12 percent of the fruits eaten by
the gardener are grown in his/her garden (EPA 1997a, Table 13-71)
7. The gardener's other characteristics and activities are
the same as those of the adult resident.
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\7\ EPA. 1997a. Exposure Factors Handbook, Volumes I, II, and
III. Office of Research and Development, Washington, D.C., EPA/600/
P-95/002Fa, b, c. August 1997; www.epa.gov/ordntrnt/ord/webpubs/
exposure/index.html.
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Fisher--We assume that the residential receptor may be a
recreational angler. Approximately 32 percent of the fish eaten by the
fisher are from a stream located near the waste management unit (EPA
1997a, Table 13-71). The fisher's other characteristics and activities
are the same as those of the adult resident.
Adult Farmer and Child of Farmer--We assume that a farmer raises
fruits, exposed vegetables, root vegetables, beef cattle, and dairy
cattle in an agricultural field located near the waste management unit.
Approximately 42 percent of the exposed vegetables, 17 percent of the
root vegetables, 33 percent of the fruits, 49 percent of the beef, and
25 percent of the dairy products eaten by the farmer and the child of
the farmer are grown/raised on the farmer's agricultural field (EPA
1997a, Table 13-71). We assume that the farmer incidentally ingests
soil from the agricultural field, and that the child of the farmer
incidentally ingests soil from his/her yard. The farmer's and child's
exposure to groundwater via ingestion, inhalation, and dermal contact
are the same as that for the adult resident and child of the resident.
EPA establishes the locations of receptors relative to waste
management units based on information obtained from national surveys.
Exposure to groundwater occurs through the use of water from drinking
water wells, and exposure via nongroundwater pathways occurs through
runoff/erosion and releases to air. Therefore, ``distance to receptor''
for groundwater exposure pathways actually is the distance to the
drinking water well that the receptor is using (the ``receptor well'').
``Distance to receptor'' for nongroundwater pathways is the distance to
the residence where the receptor is inhaling air or contacting soil,
the distance to the garden where the receptor is growing fruits and
vegetables, or the distance to the field where the receptor is growing
crops or raising livestock. Consequently, EPA uses different databases
to establish ``distance to receptor,'' depending on whether we are
evaluating a groundwater or a nongroundwater pathway.
For analysis of the nongroundwater pathway (air pathways and
erosion/runoff) risks in the deterministic analysis we assume that the
receptors live either 75 meters (m) (high end) or 300 m (central
tendency) from the waste management unit. The distance of 250 feet (ft)
(approximately 75 m) is based on the actual measured distance to the
nearest resident for the worst-case facility evaluated in the risk
assessment conducted to support the ``Hazardous Waste Treatment,
Storage, and Disposal Facilities--Organic Air Emissions Standards for
Process Vents and Equipment Leaks Final Rule'' (55 FR
[[Page 46486]]
25454), and was used as distance to the nearest resident for that
rulemaking. In the same risk assessment, EPA identified the receptor
distance of 1000 ft (approximately 300 m) as the median distance in a
random sample of distances to the nearest residence. For the
probabilistic analysis, we assume the receptors live either 50, 75,
100, 200, 300, 500, or 1000 m from the waste management unit. For air
pathway analyses, we always assume that the receptors (including
cattle) are located along the centerline of the area most greatly
impacted by air releases from the waste management units. However, at
distances of a few hundred meters from the waste management unit, the
air concentrations within about a 100 meter lateral distance do not
vary appreciably.
For deterministic analyses we assume that a receptor well is
located 102 m (high end) or 430 m (central tendency) from the waste
management unit, and that the receptor well is located on centerline of
the contaminant plume (high end) or halfway between the centerline and
the edge of the contaminant plume (central tendency). The 102 m
distances is the 10th percentile value in the distribution of distances
derived from EPA's 1988 survey of Solid Waste (Municipal) Landfill
Facilities (DPRA 1993 8). The 430 m value is the 50th
percentile value in that same distribution. For the Monte Carlo
analysis, the distance from the waste management unit to the receptor
well is based on the complete distribution of distances to receptor
well reported by the survey respondents, and ranges from 0.02 m (the
location of the closest reported well was 0 m) to 1604 m (the maximum
distance for which EPA requested receptor well information was 1 mile).
For the Monte Carlo analysis we assume that the receptor well is
located anywhere within the contaminant plume.
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\8\ DPRA. 1993. Parameter Values for Developing Nationwide
Regulations with the EPA's Composite Model for Landfills (EPACML).
EPA Contract Number 68-WO-0029. July.
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The Risk Assessment Technical Background Document for the
Chlorinated Aliphatics Listing Determination provides a complete
discussion of the values of additional parameters that define the
characteristics of each receptor, such as the amounts of contaminated
food and water they ingest, their inhalation rates, and how long they
live near the waste management unit.
d. How Did EPA Predict What Contaminant Concentrations Are at the
Points Where Receptors Are Exposed?
EPA conducts contaminant fate and transport modeling and indirect
exposure modeling to determine what the concentrations of contaminants
will be in the media (for example, groundwater, air, soil, food items)
that the receptor comes into contact with. These concentrations are
called ``exposure point concentrations'' (that is, they are the
contaminant concentrations at the point where the receptor is exposed
to the contaminants). There are a number of computer-based models and
sets of equations that EPA uses to predict exposure point
concentrations. In the following sections we briefly discuss these
models and equations and their application in the risk analyses.
i. Partitioning Model
For the landfill and the land treatment unit, EPA uses a series of
``partitioning'' equations to determine how much contaminant mass is
retained in the waste management unit and how much is released into the
environment. These equations are based upon equations presented in a
series of articles by Jury et al. (Jury et al. 1983, 1984, and 1990
9). EPA used the partitioning equations to estimate the mass
of a contaminant that will be lost from the land treatment unit due to
volatilization into the air, contaminant leaching into the subsurface,
runoff from the land treatment unit, and degradation. For the landfill
scenarios, EPA used the partitioning equations to determine how much of
the contaminant mass would be lost due to volatilization into the air;
EPA assumed that the remainder of the mass would be available to leach
into the subsurface. We assumed that volatilization losses could occur
prior to the landfill being covered with daily cover or daily waste
addition, through the daily cover or daily waste addition, and through
the cap that is placed on the landfill after closure. For the landfill,
we used toxicity characteristic leaching procedure (TCLP) analytical
results (rather than the partitioning equations) as the predictor of
leachate concentration. The TCLP is an analytical procedure that
``leaches'' a waste sample in a way that mimics the leaching of waste
in a municipal landfill. Thus, TCLP results are a proxy for the
concentrations of contaminants that would be generated in leachate if
the waste were placed in a municipal landfill.
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\9\ Jury, W.A., W.F. Spencer, and W. J. Farmer. 1983. Behavior
assessment model for trace organics in soil: i. model description.
J. Environ. Qual. 12(4):558-564.
Jury, W.A., W. J. Farmer, and W.F. Spencer. 1984. Behavior
assessment model for trace organics in soil: ii. chemical
classification and parameter sensitivity. J. Environ. Qual.
13(4):567-572.
Jury, W.A., D. Russo, G. Streile, and H.E. Abd. 1990. Evaluation
of volatilization by organic chemicals residing below the soil
surface. Water Resources Research. 26(1):13-20.
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ii. Tank Emissions Model
EPA modeled emissions from aerated biological wastewater treatment
tanks using the CHEMDAT8 model (EPA 1994b 10). We used the
emissions estimates in conjunction with the air dispersion modeling
results (see Section D.1.d.iii) to estimate constituent-specific air
concentrations and deposition rates. CHEMDAT8 accounts for most of the
competing removal pathways that might limit air emissions, including
adsorption, biodegradation, and hydrolysis. Chemicals that sorb to
solids or decompose due to either biodegradation or hydrolysis have
lower potential for emission to the air. CHEMDAT8 is considered to
provide reasonable to slightly high estimates of air emissions.
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\10\ EPA. 1994b. CHEMDAT8 User's Guide, EPA-453/C-94-080B.
Office of Air Quality Planning and Standards, US Environmental
Protection Agency, Research Triangle Park, NC, November. This model
is publicly available from EPA's Web page at http://www.epa.gov/ttn/
chief/software.html.
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CHEMDAT8 requires that the user specify parameters relating to tank
characteristics, waste characteristics, contaminant physical and
chemical properties, and location-specific meteorological conditions
(for example, windspeed and temperature). The tank characterization
data required by the model include both tank physical parameters (for
example, tank dimensions) and tank operating parameters (for example,
the number of aerators in the tank). In the absence of site-specific
data, we developed tank dimensions based on facility-reported
wastewater generation rates, an assumed wastewater depth in the tank of
15 feet, and a retention time in the tank of two days. We selected
operating parameters that we believe represent typical operating
conditions of an aerated tank. The Risk Assessment Technical Background
Document for the Chlorinated Aliphatics Listing Determination provides
a complete list of the parameters used in the CHEMDAT8 model.
iii. Air Dispersion and Deposition Model
We used EPA's Industrial Source Complex Short Term model (version
3;
[[Page 46487]]
ISCST3 11) to estimate the dispersion and deposition of
vapors emitted from the wastewater treatment tank, the municipal
landfill, the onsite industrial landfill, and the land treatment unit.
EPA also used ISCST3 to estimate the dispersion and deposition of
particulate emissions from the land treatment unit. For the land
treatment unit, EPA used equations documented in EPA's ``Compilation of
Air Pollutant Emission Factors (AP-42)'' (EPA 1985) 12 to
estimate particulate emissions resulting from wind erosion and tilling
activities. Vapor emissions from the landfill and the land treatment
unit were estimated using the partitioning models discussed in Section
III.D.1.d.i. Vapor emissions from the wastewater treatment tank were
estimated using the CHEMDAT8 model discussed in Section III.D.1.d.ii.
ISCST3 was used to estimate the air concentration of vapors, wet
deposition of vapors, the air concentration of particulates, wet
deposition of particulates, and dry deposition of particulates. We
calculate dry deposition of vapors using the air concentration of
vapors and a contaminant deposition velocity.
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\11\ EPA. 1995. User's Guide for the Industrial Source Complex
(ISC3) Dispersion Models (Draft) (Revised). Volume I. EPA-454/B-95-
003a. Office of Air Quality Planning and Standards, Emissions,
Monitoring and Analysis Division, Research Triangle Park, NC. The
ISCST3 model and meteorological preprocessor, PCRAMMET, and related
user's guides can be accessed and downloaded through the Internet
from the Support Center for Regulatory Air Models (SCRAM) web page
(http://www.epa.gov/scram001). The SCRAM is part of EPA's Office of
Air Quality Planning and Standards (OAQPS) Technology Transfer
Network (TTN).
\12\ EPA. 1985. Compilation of Air Pollutant Emission Factors,
AP-42, Fifth Edition, Volume I: Stationary Point and Area Sources.
Office of Air Quality Planning and Standards, Emissions Inventory
Group, Research Triangle Park, NC. AP-42 can be downloaded through
the Internet at http://www.epa.gov/ttn/chief/ap42.html.
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iv. Overland Transport Model
The Universal Soil Loss Equation (USLE) is an erosion model
originally designed to estimate long-term average soil erosion losses
to a nearby surface water body from an agricultural field having
uniform slope, soil type, vegetative cover, and erosion-control
practices. We used a modified form of the USLE to estimate the mass of
soil lost per year per unit area from the land treatment unit and
deposited directly onto the adjacent receptor site (agricultural field,
residential lot, home garden) and into a nearby stream.
Because the basic USLE equation estimates only soil erosion to
surface water bodies, EPA assumes the receptor location is located
between the land treatment unit and the surface water body. The area
including the land treatment unit, the receptor site, and the
intervening area is considered for the purposes of the analysis to be
an independent, discrete drainage subbasin that is at steady-state. We
estimate the soil erosion load from the subbasin to the surface water
body using a distance-based sediment delivery ratio, and consider that
the sediment not reaching the surface water body is deposited evenly
over the area of the subbasin. Using mass balance equations, EPA
estimates contaminant contributions to the surface water body and the
receptor soil. ``Mass balance equations'' are equations that honor the
law of conservation of mass, that is, the mass of a contaminant that is
present at the beginning of the analysis (for example, the mass of a
contaminant in a waste placed in a waste management unit) is equal to
the mass of the contaminant present at the end of the analysis. Even
though at the end of the analysis the contaminant mass may be
partitioned into a number of environmental ``compartments'' (for
example, the waste management unit, the soil, and the surface water
body), there is in total no more or no less mass than was present at
the start of the analysis.
Contaminated particles are transported from the land treatment unit
to receptor sites via air deposition as well as runoff/erosion. We
applied mass balance for each area of interest (for example, buffer
area between source and receptor site, receptor site, or surrounding
area). Consequently, the respective air deposition value for each area
of interest is included in the evaluation of the mass balance. We
considered that the air deposition over the entire subbasin area is
uniform and equal to the air deposition modeled for the receptor site.
v. Groundwater Model
We used EPA's Composite Model for Leachate Migration with
Transformation Products (EPACMTP; EPA 1996a, 1996b, 1996c, 1997
13) to model the subsurface fate and transport of
contaminants that leach from the waste management units (the land
treatment unit or the landfill) and migrate to a residential drinking
water well or discharge from groundwater to surface water.
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\13\ EPA. 1996a. EPA's Composite Model for Leachate Migration
with Transformation Products (EPACMTP) Background Document. Office
of Solid Waste, Washington, DC.
EPA. 1996b. EPA's Composite Model for Leachate Migration with
Transformation Products (EPACMTP) Background Document for the Finite
Source Methodology. Office of Solid Waste, Washington, DC.
EPA. 1996c. EPA's Composite Model for Leachate Migration with
Transformation Products (EPACMTP) Background Document for Metals.
Office of Solid Waste, Washington, DC.
EPA. 1997. EPA's Composite Model for Leachate Migration with
Transformation Products (EPACMTP) User's Guide. Office of Solid
Waste, Washington, DC.
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Precipitation that migrates through the waste management unit
generates leachate, which infiltrates the bottom of the waste
management unit and migrates into the unsaturated zone. The
contaminants dissolved in the leachate subsequently are transported in
the aqueous phase through the unsaturated zone to the underlying
saturated zone and then downgradient to a receptor (drinking water)
well or surface water body located at a specified distance from the
boundary of the waste management unit. EPACMTP accounts for the
following processes affecting contaminant fate and transport:
advection, hydrodynamic dispersion, equilibrium linear or nonlinear
sorption by the soil and aquifer solids (both in the unsaturated and
saturated zones), and contaminant hydrolysis. In the event that the
hydrolysis daughter products are toxic and their chemical properties
are known, the model also accounts for the formation and subsequent
fate and transport of the daughter products.
The landfill analysis employed two simplifying assumptions. First,
we assumed that contaminant leaching from the landfill does not occur
until after the landfill closes (that is, after 30 years). EPA made
this assumption because of complexities associated with linking the
output of the landfill partitioning equations (discussed in Section
III.D.1.d.i.) and the groundwater model, EPACMTP. Second, we assumed
that there are no contaminant losses due to mechanisms other than
leaching after the landfill has been closed (that is, after 30 years).
This effectively over-estimates the total mass of volatile contaminants
that would leach to groundwater because it does not allow contaminant
loss due to volatilization from the landfill to deplete the total
contaminant mass available for leaching from the landfill in the years
after closure. EPA determined that if volatile constituents caused
significant risk via the groundwater pathway, we would have to re-
evaluate our methodology for conducting the landfill analysis. This
situation did not occur.
vi. Surface Water Model
EPA assumed that fish are exposed to waste constituents in surface
water. Specifically, we assumed that fish are exposed to contaminants
dissolved in the water column, contaminants sorbed to suspended solids
in the water
[[Page 46488]]
column, and contaminants associated with the bed sediment in the
surface water body. The method used to estimate how management of
chlorinated aliphatics wastewaters and wastewater treatment sludges
impacts surface water is based on the methodology presented in Addendum
to Methodology for Assessing Health Risks Associated with Indirect
Exposure to Combustor Emissions (EPA 1993) 14. The model
accounts for six ways in which contaminants may enter the surface water
body: (1) contaminants may be sorbed to eroded soils that enter the
surface water body, (2) contaminants may be dissolved in runoff that
enters the surface water body, (3) contaminants may be bound to
airborne particles that are deposited on the surface water body, (4)
vapor phase contaminants in air may be deposited on the surface water
body in precipitation (that is, wet deposition of vapor phase
contaminants), (5) vapor phase contaminants in air may enter the
surface water body through direct diffusion from the air, and (6)
contaminants in groundwater may discharge into the surface water body.
The model also accounts for processes that remove contaminants from the
surface water body. These include: (1) volatilization of contaminants
that are dissolved in surface water and (2) burial of contaminants in
the sediment at the bottom of the surface water body. The model assumes
that the impact to the water body is uniform, which is more realistic
for smaller surface water bodies than for larger ones. The model
estimates the concentrations of contaminants in the water column and
bed sediment. We used the water column or bed sediment concentrations
and bioconcentration factors (BCFs), bioaccumulation factors (BAFs), or
biota-sediment accumulation factors (BSAFs) to estimate contaminant
concentrations in fish tissue.
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\14\ EPA. 1993. Addendum to Methodology for Assessing Health
Risks Associated with Indirect Exposure to Combustor Emissions. EPA/
600/AP-93003. Office of Health and Environmental Assessment,
Washington, DC.
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vii. Indirect Exposure Equations
EPA uses a series of ``indirect exposure equations'' to quantify
the concentrations of contaminants that pass indirectly from
contaminated environmental media to the receptor. For example,
contaminants that are transported in air may be deposited on plants or
onto the soil where they may accumulate in forage, grain, silage or
soil that is consumed by beef cattle and dairy cattle. Individuals may
then ingest contaminated beef and dairy products. Similarly,
contaminants may be transported in groundwater to domestic groundwater
wells where the groundwater is extracted and used for showering. The
water vapor generated in the shower may be inhaled by the receptor. The
indirect exposure equations allow EPA to calculate exposure point
concentrations for these pathways and routes of exposure. The indirect
exposure equations used by EPA to conduct the chlorinated aliphatic
wastewater, EDC/VCM sludge, and methyl chloride sludge risk assessments
are presented in the Risk Assessment Technical Background Document for
the Chlorinated Aliphatics Listing Determination.
e. How Did EPA Quantify Contaminant Exposure and Toxicity?
Exposure is the condition that occurs when a contaminant comes into
contact with the outer boundary of the body, such as the skin, mouth
and nostrils. Once EPA establishes the concentrations of contaminants
at the points of exposure, EPA can estimate the magnitude of each
receptor's exposure, or the contaminant dose. Dose is the amount of the
contaminant that crosses the outer boundary of the body and is
available for absorption at internal exchange boundaries (lungs, gut,
skin; EPA 1992 15). For example, for exposure to a
carcinogen through ingestion of contaminated drinking water, dose is a
function of the concentration of the contaminant in drinking water (the
exposure point concentration), as well as certain ``exposure factors,''
such as how much drinking water the receptor consumes each day (the
intake rate), the number of years the receptor is exposed to
contaminated drinking water (the exposure duration), how often the
receptor is exposed to contaminated drinking water (the exposure
frequency), the body weight of the receptor, and the period of time
over which the dose is averaged.
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\15\ 57 FR 22888. Final Guidelines for Exposure Assessment. U.S.
Environmental Protection Agency, May 29, 1992.
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EPA's primary source of exposure factors is the ``Exposure Factors
Handbook'' published by EPA in August 1997 (EPA 1997a 16).
For probabilistic risk analyses, EPA used the distributions of exposure
factor values provided in the Exposure Factors Handbook to develop PDFs
for exposure factors. The one situation where EPA does not develop an
expression of dose is the case where we use Reference Concentrations
(RfCs) 17 to estimate noncancer hazard for the inhalation
exposure route. In this situation, EPA calculates noncancer hazard from
concentration of the contaminant in air and the RfC, without
considering exposure factors (inhalation rate, body weight) other than
those inherent in the RfC.
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\16\ EPA. 1997a. Exposure Factors Handbook, Volumes I, II, and
III. Office of Research and Development, Washington, D.C., EPA/600/
P-95/002Fa, b, c. August 1997, www.epa.gov/ordntrnt/ord/webpubs/
exposure/index.html.
\17\ Very simply, an RfC is EPA's acceptable concentration in
air for a contaminant that causes non-cancer health effects. An RfC
is an estimate (with uncertainty spanning perhaps an order of
magnitude) of a continuous inhalation exposure to the human
population (including sensitive subgroups) that is likely to be
without an appreciable risk of deleterious noncancer effects during
a lifetime.
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We express the toxicity of contaminants as health benchmarks.
Health benchmarks include cancer slope factors (CSFs, EPA's measure of
cancer potency) 18 for oral exposure carcinogenic
contaminants; reference doses (RfDs, EPA's acceptable contaminant dose
via ingestion) 19 for oral exposure to noncarcinogenic
contaminants; inhalation CSFs for inhalation exposure to carcinogenic
contaminants; and RfCs for inhalation exposure to noncarcinogenic
contaminants. EPA derived inhalation CSFs from Unit Risk Factors (URFs)
for inhalation exposure to carcinogens. EPA uses Toxicity Equivalency
Factors (TEFs) to express the toxicity of specific dioxin congeners in
terms of the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-
TCDD) (see Section III. D.1.g.ii. for an explanation of TEFs). Health
benchmark values are available from a number of sources. For the
chlorinated aliphatics wastewater, EDC/VCM sludge, and methyl chloride
sludge risk assessments, EPA established an order of preference for the
sources of health benchmarks. The order of preference is as follows
(from most preferred to least preferred): (1) the Integrated Risk
Information System (IRIS) online database of verified health benchmarks
(http://www.epa.gov/iris/subst/index.html) 20; (2) the
Health Effects Assessment Summary Tables (HEAST;
[[Page 46489]]
EPA 1997b) 21; (3) EPA's National Center for Environmental
Assessment (NCEA) provisional values, and (3) benchmarks developed by
the California Environmental Protection Agency (CALEPA) 22.
The specific health benchmarks used in the analysis are presented in
Appendix C of the Background Document for the Chlorinated Aliphatics
Risk Assessment.
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\18\ A cancer slope factor is the slope of the dose-response
curve in the low-dose region. When low-dose linearity cannot be
assumed, the slope factor is the slope of the straight line from 0
dose (and 0 excess risk) to the dose at 1% excess risk. An upper
bound on this slope is usually used instead of the slope itself. The
units of the slope factor usually are expressed as 1/(mg/kg-day).
\19\ An RfD is an estimate (with uncertainty spanning perhaps an
order of magnitude) of a daily exposure to the human population
(including sensitive subgroups) that is likely to be without an
appreciable risk of deleterious effects during a lifetime.
\20\ EPA. 1998. Integrated Risk Information System. Online
database. (IRIS) Office of Research and Development (ORD).
Cincinnati, OH.
\21\ EPA. 1997b. Health Effects Assessment Summary Tables:
Annual Update. (HEAST) Office of Emergency and Remedial Response.
Washington, D.C. July.
\22\ California Environmental Protection Agency (CalEPA). 1997.
Air Toxics Hot Spots Program Risk Assessment Guidelines: Technical
Support Document for Determining Cancer Potency Factors. Draft for
Public Comment. Office of Environmental Health Hazard Assessment,
Berkeley, CA, www.oehha.org/ra__guidance/.
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f. What Are the Risks From Exposure to Chlorinated Aliphatics
Wastewaters, and EDC/VCM and Methyl Chloride Sludges?
The following sections discuss EPA's estimates of individual and
population risk for chlorinated aliphatics wastewaters, EDC/VCM
sludges, and methyl chloride sludges.
i. What Are the Individual Risks?
EPA combined estimates of dose and estimates of toxicity (the
health benchmarks) to calculate individual incremental lifetime
carcinogenic risk estimates and hazard quotients for the potential
contaminants of concern in chlorinated aliphatic wastewaters, EDC/VCM
sludge, and methyl chloride sludge. Complete results of these
calculations are provided in the Risk Assessment Technical Background
Document for the Chlorinated Aliphatics Listing Determination. EPA
typically considers a decision to list a waste when carcinogenic risks
are 1x10-5 or greater or when the noncancer HQ is 1 or
greater. None of the contaminants generated noncancer hazards with an
HQ greater than 1, nor did the sum of the contaminant HQs exceed 1. In
summing carcinogenic risk estimates and noncancer hazard quotients, EPA
does not sum those risks or hazards that could not occur within the
lifetime of an individual. For example, if estimated risks due to
nongroundwater pathways occur during the operating or post-closure life
of the unit (that is, due to releases to air and runoff/erosion) and
risk via the groundwater pathways are not projected to occur for
hundreds, or even thousands, of years due to long times required for
contaminant migration, then these two pathway risks would not be added
together.
The following sections present separately our deterministic and
probabilistic estimates of individual risk for:
Wastewaters from the production of chlorinated aliphatic
chemicals,
Wastewater treatment sludges from the production of EDC/
VCM, and
Wastewater treatment sludges from the production of methyl
chloride.
Chlorinated Aliphatic Wastewaters
Table III-1 summarizes the significant (greater than
1x10-5 risk estimates for chlorinated aliphatic wastewaters
managed in onsite aerated biological wastewater treatment tanks. The
highest deterministic risk estimate, 2x10-5, occurs for the
farmer. The risk is attributable to the farmer's ingestion of dioxins,
which in Table III-1 are expressed as the 2,3,7,8-tetrachlorodibenzo-p-
dioxin (TCDD) toxicity equivalent (TEQ). The farmer's high end
deterministic risk falls slightly below the 90th percentile
probabilistic risk estimate (the 80th percentile risk estimate is
1x10-5). Table III-2 summarizes our deterministic estimates
of risk due to the direct inhalation of chloroform. The high end
chloroform risks are 3x10-6 for the farmer and
2x10-6 for all other receptors. The chloroform deterministic
risk estimates for the adult receptors are roughly equal to the 97.5th
percentile probabilistic risk estimates. Although the chloroform risks
are not greater than 1x10-5, they are additive to the risks
that EPA estimated for dioxins because they would occur within the same
timeframe.
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EDC/VCM Sludges
Tables III-3 and III-4 summarize the significant (greater than
1x10-5) risk estimates for EDC/VCM wastewater treatment
sludges managed in an onsite land treatment unit. In all cases, we
estimated that the highest risk occurs for the farmer. Table III-3
presents dioxin (expressed as 2,3,7,8-TCDD TEQ) risk estimates for the
land treatment unit nongroundwater pathways. The high end deterministic
risk estimate for the farmer is 2x10-4, which also
corresponds to the 95th percentile probabilistic risk
estimate. Table III-4 presents arsenic risk estimates for the land
treatment unit groundwater pathways. The high end deterministic risk
estimate for the farmer is 1x10-5, which falls between the
97.5th percentile probabilistic risk estimate
(6x10-6) and the 100th percentile probabilistic
risk estimate (5x10-5). EPA estimates that the groundwater
pathway risks in Table III-4 would occur approximately 1500 years in
the future, whereas the dioxin nongroundwater pathway risks in Table
III-3 would occur during the assumed operating life of land treatment
unit. Table III-5 summarizes the significant risk estimates for EDC/VCM
sludges managed in an offsite municipal landfill. The risk estimates
presented in Table III-5 are arsenic groundwater pathway risks. The
high end deterministic risk estimate for the farmer is
3x10-5, which falls between the 97.5th percentile
(1x10-5) and 100th percentile (3x10-4)
probabilistic risk estimates. We estimate that the arsenic risks
attributable to the landfill (presented in Table III-5) would occur
thousands of years in the future.
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Methyl Chloride Sludges
EPA conducted a deterministic analysis to estimate nongroundwater
(air) pathway risks associated with management of methyl chloride
sludges in an onsite landfill. All nongroundwater pathway carcinogenic
risks were less than 1 x 10-8, and all noncancer HQs were
less than 0.0001.
For groundwater pathways, EPA performed a screening analysis that
maximizes estimates of risk or hazard to human receptors. EPA
calculated the carcinogenic risk for an adult who ingests (drinks) 1.4
liters of leachate from the landfill for 350 days per year for 58
years. EPA also calculated the noncancer hazard for a child who ingests
1.4 liters of leachate from the landfill for 350 days per year for 9
years. None of the noncancer HQs was greater than 1. Arsenic was the
only carcinogen with risk in excess of 1 x 10-5.
Specifically, an adult's risk due to ingesting leachate from methyl
chloride sludges for 58 years was 5 x 10-5 due to arsenic.
EPA discusses our evaluation of this risk in Section III.E.4.b.
ii. What are the Population Risks?
EPA expects that the population risks resulting from management of
chlorinated aliphatics wastewaters in tanks and EDC/VCM sludges in
onsite land treatment units and landfills are not significant. With
regard to groundwater pathway risks, EPA believes that the number of
domestic drinking water wells (thus the population) potentially
affected by groundwater contaminated with arsenic originating from the
landfill and the land treatment unit would be very small. Furthermore,
we estimate that the arsenic concentrations predicted in receptor
(drinking water) wells will result in risks only slightly above 1
x 10-5 for that very small number of people.
For nongroundwater pathways, EPA performed a screening evaluation
of population risk for the waste management scenario and pathway that
resulted in the greatest individual risk estimate of any pathway
evaluated in the chlorinated aliphatics risk assessment. Specifically,
EPA evaluated risk associated with ingestion of beef and dairy products
contaminated with dioxins derived from the onsite EDC/VCM land
treatment unit. As presented previously, under the land treatment unit
scenario the farmer's total individual excess lifetime cancer risk from
ingestion of beef and dairy was 2 x 10-4 for high end
exposures and 3 x 10-6 for central tendency exposures.
Although the individual risk estimates for the farmer exposed to
dioxins from EDC/VCM sludge managed in a land treatment unit are an
order of magnitude greater than those for the farmer exposed to dioxins
from chlorinated aliphatics wastewaters managed in tanks, is possible
that population risks resulting from releases from chlorinated
aliphatics wastewaters would exceed those resulting from releases from
EDC/VCM sludges. This might occur because there is only one land
treatment unit that is used to manage EDC/VCM sludge, and we expect
that there may be many aerated biological wastewater treatment tanks
used to manage chlorinated aliphatics wastewaters. Nevertheless, EPA
believes that it is reasonable to assume that the population risks for
the land treatment unit likely would be greater than those for the
wastewater tanks because there would need to be at least 10 wastewater
treatment tanks with surrounding cattle populations similar to that of
the land treatment unit to produce a population risk estimate
equivalent to that of the land treatment unit.
Results of the population risk analysis for the land treatment unit
indicate that 2 x 10-4 excess cancer cases would be
expected annually in a population of 1,410 individuals ingesting beef
produced from cattle raised within 2 kilometers of the land treatment
unit over a 40-year operational life for the land treatment unit (dairy
cattle are not raised in the county where the land treatment unit is
located, thus we did not evaluate ingestion of dairy products in the
population risk analysis). The average individual risk to the
population consuming beef from within the 2-kilometer radius is 2
x 10-7. We calculated the population potentially affected by
a release from the land treatment unit (1,410 individuals) from the
total estimated quantity of contaminated beef and average beef
ingestion rates (that is, we calculated how many people would be
required to consume all of the contaminated beef assuming typical rates
of beef ingestion). It is possible that the contaminated beef would be
distributed more widely throughout the population, such that the total
number of people ingesting the contaminated beef would be greater than
1,410. However, the population risk estimate would not change because
population risk is a function of the number of people who are exposed
(that is, consume contaminated beef) and each person's individual risk
(which is a function of the amount of contaminated beef a person
consumes). Consequently, as the number of people who are exposed
increases, the individual risk must decrease proportionally because
there is only a finite amount of contaminated beef, and the overall
population risk remains the same. The Risk Assessment Technical
Background Document for the Chlorinated Aliphatics Listing
Determination provides a description of the procedure used to estimate
population risks.
EPA did not estimate population risks for the other receptors for
whom we calculated individual risk estimates (residents, children,
gardeners, and fishers). Because the high end risk for the land
treatment unit scenario was driven by the ingestion of beef and dairy
products, the population risks for non-farmer receptors are expected to
be considerably lower than 2 x 10-4.
Although the population risks attributable to the management of
chlorinated aliphatics wastes are expected to be very small, EPA does
not believe it is appropriate to allow contamination from waste
management activities to cause substantial risk to nearby residents
simply because there are few individuals in the immediate vicinity of
the waste management units. 40 CFR 261.11 clearly states that wastes
are to be listed if they are ``capable of posing a substantial present
or potential hazard.'' It does not state that a large number of people
must be affected. However, population risk may be a factor that the
Agency could consider under 40 CFR 261.11(a)(3)(xi) (``other factors as
may be appropriate'').
EPA's Guidance for Risk Characterization (EPA 1995) states that
when small populations are exposed, population risk estimates may be
very small, however, ``in such situations, individual risk estimates
will usually be a more meaningful parameter for decision-makers.''
Consequently, EPA's decision to list wastes has been based primarily on
the concern over risks to those individual's who are significantly
exposed, even if there are relatively few such individuals. EPA,
however, requests comment on whether it would be appropriate to give
weight to population risk in deciding whether to list these chlorinated
aliphatic wastes as hazardous. EPA further invites comment on the
effect of this approach on the Agency's goals with respect to
environmental justice in rural areas.
g. What Is the Toxicity of COCs Identified by EPA?
The two contaminants for which EPA calculated significant risks are
dioxins (expressed as the 2,3,7,8-TCDD TEQ) and arsenic. The following
sections discuss the ways that these contaminants affect human health.
[[Page 46497]]
i. Arsenic
Arsenic is a naturally occurring element in the earth's crust that
usually exists as an inorganic or organic compound, rather than in a
free state. Arsenic that exists in compounds with elements such as
oxygen, chlorine, and sulfur is referred to as inorganic arsenic;
arsenic combined with carbon is referred to as organic arsenic. Organic
forms of arsenic are less toxic than inorganic forms.
There is clear evidence that chronic exposure to inorganic arsenic
in humans increases the risk of cancer, and EPA classifies inorganic
arsenic as a Group A--Known Human Carcinogen. Studies report that
inhalation of arsenic results in an increased risk of lung cancer. In
addition, ingestion of arsenic has been associated with an increased
risk of nonmelanoma skin cancer and bladder, liver, kidney, and lung
cancer. No information is available on the risk of cancer in humans
from dermal exposure to arsenic (EPA 1998).
ii. Dioxins
2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) belongs to the
class of compounds, chlorinated dibenzo-p-dioxins and chlorinated
dibenzofurans, that are referred to as dioxins. EPA issued a draft
Health Assessment Document for 2,3,7,8-TCDD and Related Compounds in
1994. This document is a three-volume series consisting of a complete
reassessment of the toxic effects of 2,3,7,8-TCDD (EPA 1994a, b \23\).
The document was reviewed by EPA's Science Advisory Board (SAB) but has
not yet been issued in final form.
---------------------------------------------------------------------------
\23\ EPA. 1994a. Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds. Volume II.
(Draft). Office of Research and Development, Washington, D.C.,
www.epa.gov/ord/health.
EPA. 1994b. Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds. Volume
III. (Draft). Office of Research and Development, Washington, D.C.,
www.epa.gov/ord/health.
---------------------------------------------------------------------------
EPA has classified 2,3,7,8-TCDD as a Group B2--Probable Human
Carcinogen (EPA 1997b). An increase in lung cancer risks was observed
among Japanese males exposed to 2,3,7,8-TCDD as a result of an oil
poisoning accident. Human studies have also found an association
between 2,3,7,8-TCDD and soft-tissue sarcomas, lymphomas, and stomach
carcinomas, although for malignant lymphomas, the increase in risk is
not consistent. The increase in risk is of borderline significance for
highly exposed groups and is less among groups exposed to lower levels
of 2,3,7,8-TCDD (EPA 1994b). In animal tests, TCDD is one of the most
potent carcinogens ever evaluated.
Although EPA has not developed an RfD or an RfC for 2,3,7,8-TCDD,
noncarcinogenic health effects have been reported for 2,3,7,8-TCDD. The
major noncarcinogenic effect from exposure to 2,3,7,8-TCDD is
chloracne, a severe acne-like condition that develops within months of
first exposure to high levels of 2,3,7,8-TCDD. For many individuals,
the condition disappears after discontinuation of exposure, for others
it may remain for years. There are limited human data to suggest the
doses at which chloracne is likely to occur (EPA 1994a, b).
Epidemiological studies report conflicting evidence on the
immunotoxicity of 2,3,7,8-TCDD in humans. Some studies suggest evidence
of immunotoxicity, such as alterations in lymphocyte populations, cell
surface markers, or lymphocyte proliferative response (ATSDR 1997c
\24\). However, studies have not reported changes in the immune system
directly related to 2,3,7,8-TCDD exposure (EPA 1994a, b). An
association has been reported between levels of male reproductive
hormones and 2,3,7,8-TCDD exposure. Decreased testosterone levels were
detected in several human studies, and animal data are available to
support these findings. Other effects noted in human studies include an
association between 2,3,7,8-TCDD exposure and the following:
---------------------------------------------------------------------------
\24\ ATSDR (Agency for Toxic Substances and Disease Registry).
1997c. Toxicological Profile for 2,3,7,8-Tetrachlorodibenzo-p-
dioxin. U.S. Public Health Service, U.S. Department of Health and
Human Services, Atlanta, GA.
---------------------------------------------------------------------------
An increased risk of diabetes and an elevated prevalence
of abnormal fasting serum glucose levels
The induction of cytochrome P-450 1A1, an enzyme involved
in biotransformation reactions
Elevation of gamma glutamyl transferase, a liver enzyme
A possible increased risk of endometriosis, a disease of
the female reproductive system (EPA 1994a, b).
Animal studies report reproductive and developmental effects from
exposure to 2,3,7,8-TCDD. These studies suggest that altered
development may be among the most sensitive endpoints of 2,3,7,8-TCDD
exposure. Developmental toxicity has been reported to occur in several
animal species at lower levels than male and female reproductive
toxicity effects. 2,3,7,8-TCDD appears to affect a large number of
critical developmental effects at specific developmental stages. These
changes can lead to increases in fetal mortality, disruption of organ
system structure, and irreversible impairment of organ function.
Developmental toxicity from 2,3,7,8-TCDD has been seen in fish, birds,
and mammals (EPA 1994a, b).
EPA assigned 17 dioxin and furan congeners individual toxicity
equivalency factors (TEFs). TEFs are estimates of the toxicity of
dioxin-like compounds relative to the toxicity of TCDD, which is
assigned a TEF of 1.0. We used the TEFs identified as the I-TEFs
(International-TEFs) to conduct the chlorinated aliphatics risk
assessment because, until very recently, this is the TEF scheme EPA
scientists have recommended and used for the last 10 years (EPA 1989)
\25\ \26\. Documentation supporting the use of the TEFs has been placed
in the rulemaking record.
---------------------------------------------------------------------------
\25\ EPA. 1989. Interim Procedures for Estimating Risks
Associated with Exposure to Mixtures of Chlorinated Dibenzo-p-
Dioxins and Furans (CDDs and CDFs) and 1989 Update. EPA/625/3-89/
016. Risk Assessment Forum. March.
\26\ Proposed Rule, ``Addition of Dioxin and Dioxin-Like
Compounds; Modification of Polychlorinated Biphenyls (PCBs) Listing;
Toxic Chemical Release Reporting; Community Right-to-Know,'' 62 FR
24887, (May 7, 1997).
---------------------------------------------------------------------------
The I-TEFs are presented in Table III-6. The I-TEFs are based on a
limited data base of in vivo and in vitro toxicity testing (EPA 1989).
The World Health Organization (WHO) recently reviewed the I-TEFs (Van
den Berg et al. 1998) \27\, and determined that three of the I-TEFs,
those for 1,2,3,7,8-PeCDD (pentachlorodibenzo-p-dioxin), OCDD
(octachlorodibenzo-p-dioxin), and OCDF (octachlorodibenzofuran),
required modification (Table III-6). EPA is in the process of adopting
these modifications, and consequently reviewed the impact that the
revised (WHO-) TEFs would have on the results of the chlorinated
aliphatics risk assessment. 1,2,3,7,8-PeCDD was not detected in
dedicated chlorinated aliphatic wastewaters, dedicated EDC/VCM sludges,
or methyl chloride sludges. Consequently, the difference in the I-TEF
and the WHO-TEF for 1,2,3,7,8-PeCDD has no impact on the results of the
risk analyses presented in this section. Because of the TEF differences
for OCDD and OCDF, however, the decision to use either the I-TEFs or
the WHO-TEFs potentially may result in large differences in the
calculated TCDD TEQ concentrations for a given chlorinated aliphatics
waste sample. Nevertheless, because OCDD and OCDF contribute very
little to the actual risk attributable to dioxin compounds, the
decision to use either
[[Page 46498]]
the I-TEFs or the WHO-TEFs has negligible impact to the overall risk
results. The Risk Assessment Technical Background Document for the
Chlorinated Aliphatics Listing Determination provides separate risk
results for each of the dioxin congeners detected in the wastewaters
and sludges evaluated.
---------------------------------------------------------------------------
\27\ Van den Berg, et al. 1998. Toxic Equivalency Factors (TEFs)
for PCBs, PCDDs, PCDFs for Humans and Wildlife. Environmental Health
Perspectives, v.106, n.12, pp. 775-792. December.
Table III-6. Toxicity Equivalency Factors (TEFs) for Dioxin Compounds
------------------------------------------------------------------------
Compound I-TEF WHO-TEF
------------------------------------------------------------------------
2,3,7,8-TCDD............................ 1 same
1,2,3,4,5,7,8,9-OCDD.................... 0.001 0.0001
1,2,3,7,8,9-HxCDD....................... 0.1 same
1,2,3,4,6,7,8-HpCDD..................... 0.01 same
1,2,3,4,6,7,8,9-OCDF.................... 0.001 0.0001
1,2,3,4,7,8-HxCDD,...................... 0.1 same
1,2,3,7,8-PeCDD,........................ 0.5 1
2,3,7,8-TCDF............................ 0.1 same
1,2,3,4,7,8,9-HpCDF..................... 0.01 same
2,3,4,7,8-PeCDF......................... 0.5 same
1,2,3,7,8-PeCDF......................... 0.05 same
1,2,3,6,7,8-HxCDF....................... 0.1 same
1,2,3,6,7,8-HxCDD....................... 0.1 same
2,3,4,6,7,8-HxCDF....................... 0.1 same
1,2,3,4,6,7,8-HpCDF..................... 0.01 same
1,2,3,4,7,8-HxCDF....................... 0.1 same
1,2,3,7,8,9-HxCDF....................... 0.1 same
------------------------------------------------------------------------
h. What Is the Uncertainty in the Human Health Risk Results?
EPA typically classifies the major areas of uncertainty in risk
assessments as parameter uncertainty, scenario uncertainty, and model
uncertainty. This section identifies the primary sources of each of
these types of uncertainty in the chlorinated aliphatics risk
assessment, and qualitatively describes how each may influence the
results of the risk assessment.
Many of the parameters that we used to quantify contaminant fate
and transport and contaminant exposure and dose either were not
measured or could not be measured precisely and/or accurately. Some of
the most important and sensitive parameters in our analyses include
those that describe waste composition; waste management practices; site
characteristics (for example, hydrogeological, topographical,
meteorological, and soils data); the physiologic and behavioral
exposure characteristics of the receptors; the physical, chemical, and
biochemical properties of the contaminants; and toxicological effects.
We believe that the primary sources of parameter uncertainty include
the following:
The risk analyses were based on a limited set of waste
sample data. It is possible that these data do not represent the
true distribution of contaminant concentrations in the waste
categories evaluated, resulting in either an overestimation or
underestimation of the actual risk to receptors.
EPA obtained little site-specific information regarding
waste management units for the chlorinated aliphatics industry,
necessitating that we make a number of assumptions regarding waste
management in off-site landfills, the land treatment unit, and
wastewater tanks. Many of the facilities reported using offsite
nonhazardous landfills to dispose of EDC/VCM sludges. We assumed
that these landfills are municipal landfills, and modeled typical
municipal landfills based on available data. Our major assumptions
about the municipal landfills that have the effect of decreasing our
risk estimates are that the landfills have daily covers and run-on/
run-off controls. Our major assumptions about the municipal
landfills that have the effect of increasing our risk estimates are
that the landfills are not lined and have no leachate collection
systems. For the land treatment unit, we assumed that no run-on/run-
off controls were present to mitigate risk. We assumed that the
industry's wastewater treatment tanks are uncovered (which increases
our risk estimates), are aerated (which increases our risk
estimates), employ biological treatment techniques (which decreases
our risk estimates), have structural integrity (which decreases our
risk estimates), and have spill and overflow controls (which
decreases our risk estimates).
We typically used regional databases to obtain the
parameter values necessary to model contaminant fate and transport.
Because the data that we used are not specific to the facilities at
which the actual wastes are managed, the data represent our best
estimates of actual site conditions. Use of these databases in lieu
of site-specific data may result in either overestimates or
underestimates of risk.
Sources of uncertainty in toxicological benchmarks
include one or more of the following: extrapolation from laboratory
animal data to humans, variability of response within the human
population, extrapolation of responses at high experimental doses
under controlled conditions to low doses under highly variable
environmental conditions, and adequacy of the database (number of
studies available, toxic endpoints evaluated, exposure routes
evaluated, sample sizes, length of study, etc.). Toxicological
benchmarks are designed to be conservative (that is, overestimate
risk) because of the uncertainties and challenges associated with
condensing toxicity data into a single quantitative expression.
Therefore, use of the current toxicological benchmarks most likely
overestimated risk for the pathways evaluated.
EPA estimated the risk of developing cancer from the
estimated lifetime average daily dose and the slope of the dose-
response curve. A cancer slope factor is derived from either human
or animal data and is taken as the upper bound on the slope of the
dose-response curve in the low-dose region, generally assumed to be
linear, expressed as a lifetime excess cancer risk per unit
exposure. However, individuals exposed to carcinogens in the first
few years of life may be at increased risk of developing cancer. For
this reason, EPA recognizes that significant uncertainties and
unknowns exist regarding the estimation of lifetime cancer risks in
children. We also note that the analysis of cancer risks in children
has not been externally peer reviewed.
We expect that the various sources of parameter uncertainty in our risk
assessment counterbalance each other, such that parameter uncertainty
will not result in a significant overall increase or decrease in risk.
Scenario uncertainty results from the assumptions we make regarding
how receptors become exposed to contaminants. This uncertainty occurs
because of the difficulty and general impracticality of making actual
measurements of a receptor's exposure. Exposure modeling relies heavily
on default assumptions regarding population activity patterns,
mobility, dietary habits, body weights, and other factors. Because the
risk estimates presented in today's notice are for hypothetical chronic
exposures and are designed to provide a realistic range of potential
receptor exposure scenarios, we develop predictions of long-term
average exposures for each receptor. Although it is possible to study
various populations to determine their exposure parameters (for
example, age-specific soil ingestion rates or intake rates for food) or
to assess past exposures (epidemiological studies) or current
exposures, risk assessment is about prediction. Therefore, long-term
exposure monitoring in this context is infeasible. The double-high end
deterministic approach coupled with the probabilistic approach is
designed to provide reasonable estimates of potential long-term
exposures for various receptors. The Exposure Factors Handbook provides
the current state-of-the-science regarding exposure modeling and
assumptions and was used in the risk assessment. To the extent that
actual exposure scenarios vary from the assumptions we used, risks
could be underestimated or overestimated. Although there could be
individuals living near a waste disposal site who have higher exposures
than those presented, it is more likely that actual exposures for most
of these individuals would fall within the predicted range, and,
moreover, would be similar to those predicted for the central tendency
or 50th percentile.
Models and their mathematical expressions are simplifications of
reality that are used to approximate real-world conditions and
processes, and their
[[Page 46499]]
relationships. Models do not include all parameters or equations
necessary to express reality because of the inherent complexity of the
natural environment, and the lack of sufficient data to describe the
natural environment. Consequently, models are based on numerous
assumptions and simplifications, and reflect an incomplete
understanding of natural processes. We selected the models used in this
risk assessment, described in Section III.D.1.d, based on science,
policy, and professional judgment. We selected the wastewater emissions
model, the air dispersion and deposition models, the indirect exposure
equations, and the groundwater model because they provide the
information needed for this analysis and because we generally consider
them to be state-of-the-science. Even though the models used in the
risk analysis are used widely and have been accepted for numerous
applications, they each retain significant sources of uncertainty that
as a whole could result in either an overestimation or underestimation
of risk.
One of the sources of uncertainty is our assumption that vapor
emissions of dioxins from chlorinated aliphatics wastewaters and
wastewater treatment sludges do not appreciably sorb to particulate
matter in the ambient air in approximately 1.2 minutes, the average the
time required for emissions from the waste management units to reach a
receptor located 300 meters away (our central tendency distance to
receptor). Sorption of dioxins onto particles in air would remove
dioxins from the vapor phase, thereby reducing the vapor-phase
diffusion of dioxins into plants. As a result, our calculated dioxin
concentrations in plants, and in animals consuming plants (particularly
grasses), are higher than they would be if we assumed that some
fraction of the vapor phase dioxin irreversibly partitions onto
particles in the ambient air. However, given the uncertainties
regarding rates of dioxin partitioning, magnitude of partitioning, and
other factors potentially influencing dioxin sorption onto particles
(such as temperature, humidity, and particle size, type and density),
we believe our assumption that dioxins remain as vapors during their
transport from the waste management unit source to the receptor
location is appropriate. Because we understand that our assumption
results in increased risk estimates, we are soliciting public comment
on this issue. We also charged peer reviewers with providing comment on
the issue during the peer review process, discussed in Section
III.D.3., below.
2. What Are the Potential Risks to Ecological Receptors?
EPA conducted an ecological risk screening analysis for the tank
scenario for chlorinated aliphatics wastewaters, the land treatment
unit and landfill waste management scenarios for EDC/VCM sludges, and
for the landfill waste management scenario for methyl chloride sludges.
The purpose of this analysis was to identify whether there is potential
for adverse ecological effects resulting from the management of
chlorinated aliphatics wastewaters, EDC/VCM sludges, and methyl
chloride sludges. The screening analysis compares the modeled media
concentrations to protective media concentrations in the form of a
hazard quotient. When the hazard quotient exceeds 1, there is potential
for adverse effects. If the hazard quotient is less than 1, we do not
expect adverse effects for a particular ecological receptor. The amount
by which the hazard quotient exceeds 1 suggests the potential for
adverse ecological effects; however, the screening results do not
demonstrate actual ecological effects, nor do they indicate whether
those effects will have significant implications for ecosystems and
their components.
For the screening analysis, EPA applied a methodology designed to
evaluate the potential for adverse ecological effects for selected
receptors in generalized terrestrial and freshwater aquatic systems.
The ecological risk screening analysis focused on a limited set of
constituents of concern that were modeled for the human health risk
analysis. For the selected ecological receptors, we developed
protective contaminant concentrations in soil, sediment, and surface
water that are based on conservative assumptions regarding exposure
pathways and dietary preferences. The analysis included the following
steps: (1) we developed chemical stressor concentration limits (CSCLs)
\28\; (2) we compared the CSCLs to exposure point concentrations and
calculated hazard quotients; and (3) we characterized key uncertainties
and their impact on hazard quotients. We describe the results of this
process in detail in the Risk Assessment Technical Background Document
for the Chlorinated Aliphatics Listing Determination.
---------------------------------------------------------------------------
\28\ Chemical stressor concentration limits are the containment
concentrations in environmental media that are presumed to cause de
minimis effects to ecological receptors.
---------------------------------------------------------------------------
Based on the results of the analysis, we do not anticipate
significant risk for the ecological receptors evaluated under either
the high end or central tendency chlorinated aliphatic wastewater tank,
EDC/VCM landfill, or methyl chloride landfill scenarios. However, there
is indication of potential significant risk to ecological receptors
under both the high end and central tendency EDC/VCM land treatment
unit scenarios. These results support our conclusions for the human
health risk analyses for EDC/VCM and methyl chloride sludges, that is,
that there are risks posed by the management of EDC/VCM sludges in land
treatment units, but not by the management of EDC/VCM sludges or methyl
chloride sludges in landfills. Although we did not explicitly consider
risks to threatened or endangered species, the CSCLs are protective
media concentrations based on Agency-wide standards (e.g., Ambient
Water Quality Criteria) and no observed adverse effects levels. The
protective nature of the CSCLs implies some degree of protection for
species already considered to be under stress. The ecological risk
screening results are described in detail in the Risk Assessment
Technical Background Document for the Chlorinated Aliphatics Listing
Determination.
3. Did EPA Conduct a Peer Review of the Risk Assessment?
The Agency has submitted the risk assessment to three independent
experts for peer review. Their comments have been received and are in
the docket for today's proposed rule. Due to the time constraints for
proposal of this rule, the Agency has not yet reviewed and addressed
those comments. Both the peer review comments and the public comments
will be addressed in the final rulemaking.
E. Waste-Specific Listing Determination Rationales
This section presents the rationale for today's proposed listing
determinations for each of the identified categories of wastewaters and
wastewater treatment sludges from the chlorinated aliphatic industry.
EPA considered the listing criteria set out in 40 CFR 261.11, as
incorporated into the risk assessments presented in Section III.D.
above, as well as any other information relevant to the criteria, in
making each of the listing determinations presented in this section.
The criteria provided in 40 CFR 261.11 include eleven factors for
determining ``substantial present or potential hazard to human health
and the environment.'' As previously discussed at the beginning of
Section III.D., nine of these factors relate to the risk assessments
(constituent toxicity, concentration, waste quantity, migration
potential, persistence, degradation
[[Page 46500]]
potential, bioaccumulation potential, plausible mismanagement, and
other regulatory actions). Damage incidents (261.11(a)(3)(ix)) are
investigated, and those that can be attributed to the wastes being
evaluated are identified and considered in our evaluation.
The following sections presents the rationale for each of the
proposed listing determinations for wastes generated by the chlorinated
aliphatics industry. Our rationale includes the results of our
consideration of each of the factors listed above, the results of our
risk assessment and other factors as may be appropriate.
1. Chlorinated Aliphatics Wastewaters
a. Wastewaters From the Production of Chlorinated Aliphatics
As explained previously in Section III.A.1., the Agency segregated
wastewaters from the chlorinated aliphatics industry into two waste
groupings. Based upon current waste management practices, we grouped
all chlorinated aliphatic wastewaters, except for those wastewaters
generated from the production of vinyl chloride monomer using mercuric
chloride catalyst in an acetylene-based process, into a single waste
category for the listing determination investigation. We decided to
study these wastewaters collectively because most chlorinated aliphatic
manufacturers commingle wastewaters generated by individual processes
prior to treating the wastewaters in a common wastewater treatment
system. 29 In addition, many process wastewaters generated
from the production of chlorinated aliphatic hydrocarbons contain
similar constituents of concern.
---------------------------------------------------------------------------
\29\ See Appendix D to Listing Background Document for the
Chlorinated Aliphatic Listing Determination.
---------------------------------------------------------------------------
EPA is proposing to list as hazardous process wastewaters generated
from the production of chlorinated aliphatic hydrocarbons (other than
those wastewaters generated from the production of vinyl chloride
monomer using mercuric chloride catalyst in an acetylene-based process,
discussed later in Section III.E.1.b of this preamble). The wastewaters
meet the criteria set out at 40 CFR 261.11(a)(3) for listing a waste as
hazardous and are capable of posing a substantial present or potential
hazard to human health or the environment when mismanaged. As already
described in the risk assessment results in Section III.D.1.f. of this
preamble, we identified risks of concern associated with air releases
of dioxins from wastewater treatment systems. The results of our risk
analysis, which explicitly considers the factors listed in 40 CFR
261.11(a)(3)(i)-(x), shows potential risks of concern for the farmer
and child of farmer receptors, where the contaminants of concern are
dioxins. The risk assessment results were presented previously in Table
III-1 of Section III. D.1.f.
i. What Information Led EPA To Propose To List as Hazardous Process
Wastewaters From the Production of Chlorinated Aliphatic Hydrocarbons?
Responses to the 1996 RCRA Section 3007 chlorinated aliphatic
industry survey indicated that approximately 11.5 million metric tons
of chlorinated aliphatic wastewaters are generated annually. Survey
responses and other publicly-available information also indicate that
virtually all chlorinated aliphatic manufacturers treat these
wastewaters in on-site, tank-based wastewater treatment systems prior
to direct discharge of these wastewaters in accordance with facility-
specific NPDES permits. Other wastewater management practices
identified include discharge off-site to either publicly-or privately-
owned treatment works (POTW, PrOTW), and storage and treatment in tanks
prior to disposal in on-site underground injection wells. None of the
facilities that responded to the questionnaire indicated that
chlorinated aliphatic wastewaters currently are managed in surface
impoundments.
The Agency evaluated air pathway (vapor emissions) risks associated
with the management of chlorinated aliphatics in wastewater treatment
tanks. Our analysis of air emissions from the treatment of wastewaters
was limited to an evaluation of air emissions from tank-based systems
because the results of the RCRA Section 3007 survey showed that the
chlorinated aliphatics industry manages wastewaters exclusively in
tanks. Surface impoundments currently are not being used by this
industry for the treatment of wastewaters, and based upon a review of
industry trends, we anticipate that this industry will not use surface
impoundments in the future. First, all of our data indicate that
surface impoundments are no longer used by the chlorinated aliphatics
manufacturers. In the 1992 RCRA 3007 survey responses, 5 facilities
indicated they were using surface impoundments in the treatment of
wastewater. In the 1997 RCRA 3007 survey update, only two facilities
indicated they were using surface impoundments. We contacted the five
facilities to confirm whether or not surface impoundments were being
used, and learned that all of the impoundments had closed. Second, we
do not believe it is likely that established tank-based wastewater
treatment systems would be abandoned for surface impoundments-based
systems, given that chlorinated aliphatic manufacturers have made the
decision to convert to tank-based systems outside of regulations and
after having considered other variables (e.g., liability concerns) and
weighing all risks and benefits of tank-based systems. Further,
impoundment-based systems are land intensive and land is valuable,
particularly in industrial areas. Once a facility has reclaimed land
previously used for surface impoundments, the facility is likely to
then use that land for higher value operations. Therefore, we did not
view surface impoundments as a plausible management for wastewaters
within this industry.
Given that wastewaters are managed in aerated biological treatment
tanks, the emissions pathway of most concern is air emissions. Although
such tanks often are open and may facilitate air releases, wastewater
treatment tanks do restrict or eliminate the possibility of releases to
groundwater via leaching. Tanks used to store and treat wastewaters
generally are equipped with overflow and spill controls and are managed
in compliance with structural integrity requirements that restrict the
physical migration of wastes from the unit into the surrounding soil.
However, given that a majority of the tanks used to treat chlorinated
aliphatic wastewaters are designed to allow for aeration of the
wastewater, these units may not completely control releases due to
vapor emissions. Therefore, EPA determined that contaminant transport
via air releases from tank-based systems was the most logical source of
potential risk from managing these wastewaters.
EPA collected 41 samples of chlorinated aliphatic wastewaters
generated at 15 facilities. From the samples and analytical results we
selected data for our risk analysis that represent wastewaters at the
point where they are commingled prior to treatment. Since it is common
for wastewaters to be combined prior to treatment in on-site wastewater
treatment facilities, these commingled wastewaters are most
representative of the wastewaters that actually are managed in tanks.
Further, because the RCRA Section 3007 survey responses indicated that
some facilities may commingle chlorinated aliphatic process wastewater
with non-chlorinated aliphatic (e.g., petroleum refinery) process
wastewater prior to treatment, we conducted our risk assessment using
only waste characterization and volume data
[[Page 46501]]
representing ``dedicated'' wastewaters. We used data from these
facilities to ensure that the results of our risk assessment would
reflect only risks associated with the management of chlorinated
aliphatic wastewaters.
We also centered our analysis on an evaluation of chlorinated
aliphatic wastewaters not currently defined as hazardous waste, and
that are managed in aerated, uncovered biological treatment tanks.
While not every facility currently uses biological treatment, this was
the predominant practice observed during facility site visits and
indicated in the RCRA Section 3007 survey. The risk analysis assumed
that biological treatment occurs in aerated, uncovered tanks, because
these conditions are typical for biological treatment in tanks and were
confirmed to be occurring at some chlorinated aliphatic facilities
treating non-hazardous, dedicated chlorinated aliphatic wastewaters.
Also, because aeration increases air emissions, this scenario is
expected to result in the highest risk estimates (compared with non-
aerated and/or covered tanks). Based upon survey response information
and follow up inquiries with facility personnel, biological treatment
in uncovered, aerated tanks was considered to be a plausible management
scenario for wastewaters in the chlorinated aliphatics industry.
The risks associated with vapor emissions of dioxin, as presented
previously in Table III-1 in Section III.D.1.f., are significant for
two receptors, the farmer and the farmer's child, and for one exposure
route, the consumption of beef and dairy products. The high-end cancer
risk for the farmer is 2E-05 and the central tendency risk is 4E-07. As
explained previously, this risk is attributed to a local farmer's
ingestion of dioxin due to his consumption of fruits, vegetables, beef
and dairy products, all of which are grown or raised in an agricultural
field located near a wastewater treatment unit used to treat
chlorinated aliphatic wastewaters, as well as the farmer's incidental
ingestion of soil from the agricultural field (see Section III.D.1.c).
The high-end cancer risk for the farmer's child is 7E-06 and the
central tendency risk is 3E-07. EPA also ran a Monte Carlo risk
assessment on the air releases from these tanks. Probabilistic risk
assessment results showed a risk of 1E-4 at the 95th percentile for the
farmer, and for the child of farmer. This confirms the reasonableness
of the deterministic analysis and the fact that regulation would be
necessary to reduce the risk from the tank emissions to protect the
farmers. At the 50th percentile, the probabilistic risk was 2E-7 for
the farmer and the child of farmer.
As described in Section III.D.1.f. of this preamble, the high-end
parameters used in the risk assessment for dioxin emissions from
wastewater treatment tanks were waste concentration and exposure
duration. These results are based upon a concentration of dioxin in
wastewaters associated with the highest concentration of dioxin we
found for the wastewater samples used in the analysis. Further
discussion of the assumptions and parameters used in the risk
assessment is provided in Section III.D. of this preamble and in the
Risk Assessment Technical Background Document for the Chlorinated
Aliphatics Listing Determination that is in the docket for today's
proposed rule.
Our analyses also showed marginal risks of concern for the farmer,
child of farmer, home gardener, adult and child resident, and fisher,
from direct inhalation of chloroform. The high-end cancer risk for the
farmer from direct inhalation of chloroform is 3E-06. In addition, the
high end cancer risk to the child of farmer, child resident, adult
resident, home gardener, and the fisher from direct inhalation of
chloroform is 2E-06. The central tendency risk from chloroform
inhalation for the farmer, child of farmer, child resident, home
gardener, fisher and adult resident is 8E-08.
EPA is confident that the constituents of most concern, dioxins and
chloroform, were identified. In addition, we are confident that the
assumptions and parameter values used in our risk modeling reflect
``high-end'' or ``reasonable worse case'' circumstances. Risks are
unlikely to be significantly higher than shown by our modeling results.
In Section III.D.1.h. of today's preamble, we describe in more detail
sources of potential uncertainty in the risk results that may result in
under- or over-estimations of risk.
Based on an analysis of the risks associated with current
management practices, EPA is proposing to list wastewaters from the
production of chlorinated aliphatic hydrocarbons as hazardous waste
(EPA Hazardous Waste Number K173.) EPA's proposal to list this waste is
consistent with the guidance the Agency has used for determining that a
waste is hazardous (see 59 FR 66077), i.e., the risks associated with
management of wastewaters in aerated biological treatment tanks due to
vapor emissions of dioxins are above the 1E-5 listing benchmark. This
guidance also provides that EPA can consider additional factors in
cases where risk assessment results indicate a risk level of between
1E-4 and 1E-6, as is the case here. These additional factors include:
certainty of waste characterization; certainty in risk assessment
methodology; coverage by other regulatory programs; waste volume;
evidence of co-occurrence of hazardous constituents; damage cases
showing actual impact to human health or the environment; and presence
of toxicants of unknown or unquantifiable risk.
With regard to certainty of waste characterization, as explained in
Section III.D., the Agency collected and analyzed 41 samples of
wastewaters generated from the production of chlorinated aliphatic
chemicals, six of which were collected at the influent (``headworks'')
of the wastewater treatment system. Given that we used these six
``dedicated'' samples in our risk assessment, we are certain that our
analysis evaluated without question the risks attributable to the
wastewaters of concern.
With respect to certainty in risk assessment methodology, we note
that there is discussion of uncertainty in the risk assessment
methodology in section III.D.1.h. of today's preamble. As mentioned in
that section, we selected the models we used because we generally
consider them to be state-of-the-science, and because they are used
widely and have been accepted for numerous applications. However, as
mentioned, they each retain significant sources of uncertainty that as
a whole could result in either an overestimation or underestimation of
risk. Should the Agency determine, based upon public comment or as a
result of the peer review of the risk assessment methodology, that the
wastewater risk assessment has overestimated the risks such that a
decision to list this residual is not warranted, the Agency may
ultimately decide against listing this waste.
We considered coverage by other regulatory programs in making our
proposed listing determination for chlorinated aliphatic wastewaters.
In fact, as discussed further below, our decision to propose to list
these wastewaters and to propose technical standards to address air
emissions from treatment tanks managing these wastewaters, is directly
related to the fact that current regulatory programs do not appear to
adequately address the type of air releases from these units that
showed risk in our analysis.
Waste volume is part of our risk level calculations. As explained
in section III.D., risk is projected based on the volume of waste
managed under each modeled waste management scenario.
[[Page 46502]]
We note that there is a significant volume of chlorinated aliphatic
wastewater generated annually (11.5 million metric tons). Our risk
assessment methodology also accounts for the co-occurrence of hazardous
constituents in any particular waste. Section III.D.1.b. discusses the
number of potential constituents of potential concern identified in
each wastestream. A more detailed discussion of the constituents of
potential concern detected in each wastestream analyzed is provided in
the Risk Assessment Technical Background Document for the Chlorinated
Aliphatics Listing Determination for this rule, which is available in
the docket for today's rule.
With regard to the remaining factor in Sec. 261.11(a)(3), no actual
damage incidents have been observed (Sec. 261.11(a)(3)(ix)). However,
the risk levels indicated, large waste volumes, certainty of waste
characterization and risk assessment, coverage by other regulatory
programs, and accounting for co-occurrence of constituents in the
waste, outweigh the lack of observed damages. This is because the
potential risks associated with this wastestream would be long term.
Such risks are very difficult to directly attribute to any particular
cause and can result even in the absence of observable releases. Our
failure to observe damages incidents does not mean they have not
occurred or that risks are not being imposed upon surrounding
populations. RCRA is designed to be a prospectively-protective statute
and the Agency need not wait for actual damages to be observed.
As discussed previously, the risk assessment addresses nine of the
listing criteria in 40 CFR 261.11. EPA believes the risks resulting
from our analysis represent plausible management of these wastes
(Sec. 261.11(a)(3)(vii)) using reasonable assumptions for treatment of
wastewaters in tanks. In addition, the risk analysis was developed
using actual analytical data. However, the Agency still recognizes that
sources of uncertainty could be contributing to an overestimation of
risk. The Agency points out that risk modeling results show risks at
significant levels only in cases where sensitive input parameters are
assumed to represent high-end circumstances.
Finally, the Agency did not model wastewaters that are already
defined as hazardous wastes (i.e., wastes mixed with or derived-from
other existing listed wastes, or exhibiting a characteristic of
hazardous waste), because we assume these wastes are already, and will
continue to be, properly handled as hazardous. On-site injection of
wastewaters to a permitted UIC well also was not modeled. Although
information obtained from the RCRA Section 3007 questionnaire and other
publicly available information indicate that some chlorinated aliphatic
manufacturing facilities manage wastewaters via underground injection,
the majority of these wastewaters currently are managed as hazardous
wastes and injected into Class I permitted hazardous waste UIC wells in
accordance with approved no-migration petitions. Only one facility
manages chlorinated aliphatic wastewaters as non-hazardous waste and
injects the wastewaters in a permitted UIC well.
Although we have proposed to list this wastestream, we recognize
that our estimates of the risks associated with this wastestream are
within the range in which the Agency has stated it may consider other
factors in deciding whether to list a waste. EPA invites comment as to
whether there are other factors EPA should consider that would further
support a final decision to list this waste or that would support a
conclusion that EPA should not list this waste. EPA has, for example,
asked for comment earlier in section D.1.f.ii. regarding whether to
consider population risk.
ii. What is the Scope of Today's Proposed Listing Determination for
Chlorinated Aliphatic Wastewaters?
The scope of today's proposed listing includes all wastewaters
generated by chlorinated aliphatic production processes, except for
wastewaters generated from the production of vinyl chloride monomer
using mercuric chloride catalyst in an acetylene-based process (VCM-A
process). These wastewaters were evaluated separately (see section
III.E.1.b.). The listing description for chlorinated aliphatic
wastewaters is as follows:
K173 Wastewaters from the production of chlorinated aliphatic
hydrocarbons, except wastewaters generated from the production of
vinyl chloride monomer using mercuric chloride catalyst in an
acetylene-based process. This listing includes wastewaters from the
production of chlorinated aliphatic hydrocarbons having carbon chain
lengths ranging from one to and including five, with varying amounts
and positions of chlorine substitution.
iii. What Is the Proposed Regulatory Status of Sludges Derived From the
Treatment of Wastewaters Covered by the Proposed Listing Determination?
The Agency is proposing to amend the current RCRA regulations so
that wastewater treatment sludges generated from the treatment of
wastewaters proposed to be listed as hazardous waste K173 will not be
classified as hazardous waste as a result of the ``derived-from'' rule
(40 CFR 261.3(c)(2)(i)). The proposed amendment to the derived from
rule will exempt sludges derived from the processing or management of
proposed K173, as long as the wastes would not otherwise be defined as
hazardous waste, absent the proposed K173 listing. As presented
elsewhere in today's proposed rule, EPA has studied wastewater
treatment sludges from the chlorinated aliphatics industry and made
independent hazardous waste listing determinations for several
categories of sludges. These independent evaluations of the potential
risks associated with wastewater treatment sludges derived from today's
proposed K173 wastewaters supercede any presumed risk imparted by
application of the derived-from rule in this instance. These risk
evaluations logically should take precedent over the application of the
derived-from rule, which presumes risk absent any information on
toxicity of the treatment residual. The Agency points out, however,
that sludges and other residuals generated as a result of managing
chlorinated aliphatic wastewaters that carry waste codes other than
K173, and residuals that otherwise are listed hazardous wastes (or
exhibit a characteristic of hazardous waste) remain hazardous wastes.
EPA is today proposing to add a new paragraph (E) to the derived-
from regulations at 40 CFR 261.3(c)(2)(ii) to make clear that
wastewater treatment sludges derived-from treating K173 wastewaters
will not be hazardous waste via the derived-from rule.
iv. What Comments Is EPA Specifically Requesting on the Proposed
Listing of Chlorinated Aliphatic Wastewaters?
The Agency requests comments on the proposed listing of wastewaters
from the production of chlorinated aliphatic hydrocarbons,
specifically, how would specific areas of potential uncertainty justify
a decision to list or not list these wastewaters as hazardous.
v. How Does the Agency Propose To Address the Risks Associated With
Chlorinated Aliphatic Wastewaters Affected by the Proposed Listing?
Owners and operators of wastewater treatment units, as defined in
40 CFR 260.10, are not required to obtain a RCRA permit or comply with
the management standards of 40 CFR Parts 264 (permitted facilities) and
265 (interim status facilities) when managing hazardous wastes in such
[[Page 46503]]
units (40 CFR 264.1(g)(6) and 265.1(c)(10)). Section 260.10 defines a
wastewater treatment unit as a device which (1) is a part of a
wastewater treatment facility that is subject to regulation under
Sec. 402 or Sec. 307(b) of the Clean Water Act; (2) receives and treats
or stores an influent wastewater that is a hazardous waste, generates
and accumulates a wastewater treatment sludge that is a hazardous
waste, or treats or stores a wastewater treatment sludge that is a
hazardous waste; and (3) meets the definition of a tank or tank system.
The results of the Agency's risk assessment for chlorinated
aliphatic wastewaters shows significant risks due to air emissions of
dioxins from uncovered and aerated biological treatment tanks. The
Agency's proposed listing determination for these wastewaters alone
will not address the risk pathway of concern, due to the regulatory
exemption for wastewater treatment units. To address the risks
associated with the management of proposed K173 chlorinated aliphatic
wastewaters, the Agency is proposing to require that wastewater
treatment units used to treat chlorinated aliphatic wastewaters comply
with specific requirements in 40 CFR Parts 264 and 265, subpart CC (Air
Emission Standards for Tanks, Surface Impoundments, and Containers).
The Agency's objective is to require air emission controls for
wastewater treatment tanks managing these wastewaters to prevent the
release of dioxin vapor emissions to the environment. These proposed
requirements would be enforceable requirements of RCRA subtitle C.
By this limited proposal to change the exemption for wastewater
treatment tanks that are used to treat chlorinated aliphatic
wastewaters, which is based only on a risk assessment of certain kinds
of tanks used to treat these specific wastewaters, EPA is not reopening
any other aspect of the wastewater treatment unit exemption.
What Type of Requirements is EPA Proposing To Prevent Air Releases From
These Tanks?
EPA considered simply requiring that the tanks be ``covered'' to
prevent air releases of dioxins from K173 wastewaters. However, it
became apparent that such a simplified approach might not provide
adequate guidance to the regulated community on how to ensure they are
complying with this type of performance standard. The Agency determined
that the existing requirements for controlling air emissions from
hazardous waste tanks, in subpart CC of 40 CFR Parts 264 and 265, could
be used with some modifications to meet the goal of controlling air
emissions from tanks managing proposed K173 wastewaters.
Currently, the 40 CFR 264/265 subpart CC requirements address
volatile organic (VO) emissions from hazardous waste managed in tanks,
surface impoundments, and containers. Therefore, many of the provisions
in subpart CC (e.g., the VO concentration threshold of 500 parts per
million by weight for determining applicability of the Subpart CC
requirements) are not appropriate for dioxin emissions. However, other
provisions (namely, the technical standards for covering tanks and
controlling emissions in Sections 264.1084 and 265.1085) are
appropriate for controlling air emissions from wastewater treatment
tanks managing K173 wastewaters. Therefore, EPA is proposing to amend
the subpart CC requirements (described in more detail below) so that
specific technical standards already in subpart CC for tank emissions
apply to tanks managing K173 wastewaters. (The Agency notes that the
standards being proposed today, if finalized, will apply irrespective
of the VOC content of the wastewater.) We also recognize that dioxin
levels vary among generators, and thus are proposing a trigger level
for dioxins below which compliance with subpart CC is not required.
This is because our analytical data indicate that there is a range of
dioxin levels in the chlorinated aliphatic wastewaters.30 In
particular, two samples contained TCDD TEQ levels that were four orders
of magnitude lower than both the maximum and average TCDD TEQ
concentrations.
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\30\ See Appendix B of ``Listing Background Document for the
Chlorinated Aliphatics Listing Determination.''
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How Did EPA Develop the 2,3,7,8-TCDD TEQ Limit for Wastewaters?
EPA's first step in establishing a concentration limit for dioxins
was to determine whether we should set the limit as a 2,3,7,8-TCDD TEQ
(TCDD TEQ) concentration, or as a set of individual limits for each of
the specific dioxin congeners. We decided to set the limit as a 2,3,7,8
TCDD TEQ concentration. In making this decision, we considered the
analytical results from the six dedicated chlorinated aliphatics
headworks wastewater samples collected during the record sampling
effort (see Section III.D.1.b.). We determined that wastewaters from
the production of chlorinated aliphatic chemicals do not carry a
distinct congener ``fingerprint,'' that is, certain congeners are not
consistently more prevalent in samples of chlorinated aliphatics
wastewaters than other congeners. Because the congener composition of
chlorinated aliphatic wastewaters is not consistent or distinct,
setting limits on a congener-specific basis likely would be overly-
restrictive for some facilities. Specifically, the limit set for a
given congener would need to be protective in cases where a number of
different congeners contribute to the wastewater's dioxin toxicity or
risk (thereby requiring that lower limits be set for each congener to
ensure that the combined emissions of each congener would not generate
unacceptable risk). Such limits might be overly restrictive for those
wastewaters with a dioxin composition that is dominated by a much
smaller number of congeners. Moreover, setting the dioxin limit as a
TCDD TEQ is consistent with the approach we have taken with other
regulations, such as the Water Quality Guidance for the Great Lakes
System, 40 CFR Part 132, Appendix F.
After considering options for setting the TCDD TEQ limit, we chose
to base the TCDD TEQ limit on the lowest TCDD TEQ concentration
measured in a dedicated wastewater sample for which a high end
deterministic risk estimate is 1 x 10-5. This
concentration is 0.6 ng/L, calculated using the TEFs developed by the
World Health Organization, and corresponding to the TCDD TEQ
concentration for EPA's sample no. PL-02. (The TCDD TEQ concentration
based on the I-TEFs is 0.7 ng/L. See section III.D.1.g.ii. for an
explanation of the TEFs). The high end deterministic risk estimate was
based on the evaluation of a farmer scenario (see section III.D.1.f.)
in which the exposure duration of the farmer was set at its high end
value, 48.3 years. For the purpose of establishing the TCDD TEQ limit,
we did not set any additional values at high end. We used the ``single
high end'' approach to account for sources of uncertainty in the risk
analysis and our understanding that not all of the underlying
assumptions of the analysis may be relevant to any one chlorinated
aliphatics facility. For example, not all facilities may operate the
type of aerated biological treatment tank that was modeled, grazing of
cattle may not occur in the vicinity of all facilities on the
centerline of the contaminant plume (the farmer's risk primarily is due
to the ingestion of contaminated beef and dairy products). For
reference, the adult resident's ``single high end'' risk is 1 x
10-9 when the wastewater concentration
[[Page 46504]]
is 0.6 ng/L (based on meteorological location as a high end parameter).
The 1 x 10-5 risk result for the farmer is based on
predicted long-term average exposures assuming a wastewater TCDD TEQ
concentration of 0.6 ng/L, as well as certain other environmental and
exposure factors. This means that over the long term, the receptor is
protected at the 1 x 10-5 level when, on average, the TCDD
TEQ concentration in the wastewater is 0.6 ng/L. That is, it is
implicit in the analysis that even if there are excursions of the
wastewater TCDD TEQ concentration above 0.6 ng/L, an individual is
still protected at the 1 x 10-5 risk level if on average
the wastewater TCDD TEQ concentration is 0.6 ng/L. Today EPA is
proposing to set the TCDD TEQ limit for wastewaters at 1 ng/L. Setting
the limit at 1 ng/L accounts for the fact that we believe facilities
who comply with the requirement that the TCDD TEQ concentrations of
their wastewaters not exceed 1 ng/L will on average maintain wastewater
TCDD TEQ concentrations of approximately 0.6 ng/L or below. EPA is
proposing that wastewater treatment tanks managing proposed K173
wastewaters, where the TCDD TEQ concentration in the wastewater is
greater than or equal to 1 ng/L, comply with specific air emission
control regulations, as described in more detail below.
It is important to note that the 1 ng/L trigger level described
here for implementing the proposed tank cover requirement is not a
concentration below which the wastewater does not meet the K173
listing. This proposed listing follows what can be described as the
traditional approach EPA has taken for hazardous waste listings (i.e.,
if a particular facility's waste meets the listing description, it is
listed regardless of the concentration of constituents or waste
management practice employed). While we are proposing to list
wastewaters following this traditional approach, today's rule does
establish a concentration level for wastewaters that reflect the
Agency's concern for dioxin managed in tanks within this industry. We
seek comment on the alternative of using this level as criteria for the
listing itself. The Agency could finalize a concentration based listing
based on the 1 ng/L trigger level instead of the traditional listing
proposed today. The Agency also seeks comment on whether this
concentration-based listing approach should be implemented in the same
manner as is described in this notice (i.e., where the 1 ng/L
concentration is a trigger for requiring tank covers), or
alternatively, whether it would be more appropriate to apply the
implementation approaches described in the July 23, 1999 rulemaking for
the dyes and pigments industry (placed in the docket for today's
rulemaking for convenience).
How Will These Air Emission Controls Be Implemented?
As described below, we are proposing that generators of K173 who
manage these wastes in tanks comply with certain air emission control
requirements, including covering their tanks, unless the results of
testing the wastewater influent to the tank indicate that the dioxin
concentrations are below the 1 ng/L trigger level. Our proposed
approach consists of the following elements:
Each wastewater treatment tank managing K173 that is
not compliant with 40 CFR sections 264.1084/265.1085 of subpart CC
must be assessed to determine whether dioxin levels in the influent
to the tank exceed the trigger level.
For the purposes of this listing, the headworks of the
wastewater treatment system is assumed to be at a location directly
after steam stripping. If a facility does not utilize steam
stripping, the wastewater treatment system headworks is assumed to
be the first tank in which wastewaters are combined, accumulated or
treated after leaving the chlorinated aliphatics production process.
Tanks that are fully compliant with sections 264.1084/
265.1085 of 40 CFR subpart CC would not be subject to waste
analysis, record keeping and notification requirements proposed in
today's rule to be added to 40 CFR 265.1080(f)(1)-(5), described
below.
Once the facility has established that TCDD TEQ levels
do not exceed the trigger level for a specific tank, the facility
can assume that the TCDD TEQ levels for all downstream tanks also
are below the trigger level.
The facility must develop a waste analysis plan prior
to sampling and analysis to ensure that the measurements are
sufficiently sensitive, accurate and precise to demonstrate
compliance, as described further below. We suggest that the waste
analysis plan be developed in accordance with Agency
guidance.31
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\31\ Chapter Nine of ``Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods'' (SW-846) addresses the development and
implementation of a scientifically credible sampling plan. Chapter
One of SW-846 describes the basic elements to be included in a
Quality Assurance Project Plan (QAPP), as well as information
describing basic quality assurance (QA) and quality control (QC)
procedures. Chapter Two of SW-846 aids the analyst in choosing the
appropriate methods for samples, based upon sample matrix and the
analytes to be determined. Other appropriate sources may also be
used, including those issued by recognized national voluntary
standards setting organizations, e.g., ASTM, etc., http://
www.epa.gov/ncepihom/Catalog/EPASW-846.3.4A.html
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The initial assessment must be conducted by the
effective date of the rule. If the trigger level is exceeded,
compliance with the applicable sections of 40 CFR 264/265 subpart CC
must be accomplished within one year of the effective date.
Alternatively, the facility may implement process changes to reduce
the TCDD TEQ level below the trigger level, and repeat the initial
assessment to demonstrate that levels are now below the trigger
level, within the same one year time frame.
If it is determined that the TCDD TEQ concentration
measured during the initial assessment is below the trigger level,
re-assessment would be required (1) as a result of any process
changes that would impact dioxin wastewater levels, and (2)
annually.
If the trigger level is not exceeded, the facility must
submit a one-time notification and certification.
The facility must maintain records on site.
Sampling and Analysis
In designing the sampling program, the facility must consider any
expected fluctuations in concentrations over time. The sample design
should be described in the waste analysis plan, which must be retained
in the facility's files. The sample design must be adequate to
determine that the level of TCDD TEQ in the wastewater is above or
below the 1 ng/L at a 95 percent upper confidence limit around the
mean. This approach is being used in the comparable fuels final rule
(June 19, 1998; 63 FR 33782). See also Guidance for Data Quality
Assessment--Practical Methods for Data Analysis, EPA QA/G-9, January
1998, EPA/600/R-96/084. Under this approach, EPA is not specifying a
specific number of samples, because the number of samples required to
demonstrate that the wastewater dioxin concentration is below 1 ng/L at
the 95 percent upper confidence limit depends on how close the actual
concentration is to the regulatory limit and on the variability of the
waste. EPA is proposing that the samples used to demonstrate compliance
be grab samples collected within a time period that will accurately
account for potential variability in the wastestream, including
potential variabilities associated with batch and continuous processes.
If properly stored, the holding time for unprocessed aqueous samples of
dioxins/furans (which can be found in the Sample Collection, Handling
and Preservation section of Method 8290) allows for multiple samples to
be collected and be available should additional analysis be required to
achieve the data quality objective of determining compliance with the 1
ng/L limit at a 95% upper confidence limit around the mean.
EPA also is proposing an alternative sample design criteria. The
alternative approach is to set a maximum
[[Page 46505]]
quantitation value as an alternative to the use of the 95% upper
confidence limit around the mean. Under this approach, the Agency is
proposing that the analytical quantitation limits should be sufficient
to calculate a meaningful TCDD TEQ for comparison to the 1
ng/L trigger level. Our experience with this matrix is that
quantitation at or below 0.05 ng/L should be routinely achievable,
therefore we are proposing that the selected analytical method achieve
a precision of at least 30 percent relative standard deviation at a
calibration level of 0.05 ng/L and a recovery of greater than or equal
to 70 percent 32 (we note that if isotope-dilution methods
are used, recovery is not an issue, since this method is self-
correcting for recovery.) Under this approach, EPA is specifying that a
minimum of four grab samples be collected within a 24-hour time period.
The Agency notes that although we are considering setting a lower
calibration standard for the measurement method as an alternative to
the 95 percent upper confidence limit around the mean standard, the
regulatory language included with today's proposal reflects only the
preferred option.
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\32\ Recent recovery is from an EPA Memorandum from Barnes
Johnson, Director of the Economics, Methods, and Risk Assessment
Division, to James Berlow, Director of the Hazardous Waste
Minimization and Management Division, regarding the Office of Solid
Waste's (OSW) standing policy on the Appropriate Selection and
Performance of Analytical Methods for Waste Matrices Considered to
be ``Difficult-to-Analyze,'' January 31, 1996.
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Generators may not use process knowledge to determine whether or
not the 1 ng/L TCDD TEQ trigger level has been exceeded for the first
tanks in the wastewater treatment system where constituent
concentrations are likely to be highest. However, once the facility has
established that the trigger level is not exceeded in the influent to a
given tank, the facility may use process knowledge to determine that
dioxin levels in wastewaters managed in subsequent downstream tanks
also will not exceed the trigger level.
We are proposing that the generator maintain documentation of the:
(1) detailed standard operating procedures (SOPs) for the sampling and
analysis protocols that were employed; (2) sensitivity and bias of the
measurement process; (3) precision of the analytical results for each
batch of waste tested; and (4) analytical results.
It is the responsibility of the generator to ensure that the
sampling and analysis is unbiased, precise, and representative of the
tank influent. To show that a tank is not subject to the specific
Subpart CC requirements applicable to K173 wastewaters, a generator
must demonstrate that: (1) the maximum TCDD TEQ in the tank influent
does not exceed the 1 ng/L trigger level; and (2) the analysis could
have detected the presence of the CDD/CDF congeners at or below the
trigger level.
We are not requiring the use of SW-846 methods to comply with these
requirements. We are proposing to allow the use of alternative methods
to those included in SW-846, so long as the selected methods meet the
following performance based criteria.
The Agency will consider the analysis adequate to demonstrate that
the trigger level of 1 ng/L is not exceeded if an analysis in which
TCDD (as a surrogate for all of the CDD/CDF congeners) spiked at the
trigger level indicates that the analyte is present at that level
within analytical method performance limits (e.g., sensitivity, bias
and precision). To determine the performance limits for a method, EPA
recommends following the quality control (QC) guidance provided in
Chapters One and Two of SW-846, and the additional QC guidance provided
in Method 8290.
vi. What Comments Is EPA Specifically Requesting on the Proposed
Approach for Controlling Dioxin Air Emissions?
The Agency requests comment on the proposal to add air emission
control requirements for tanks used to manage chlorinated aliphatic
wastewaters. In addition, the Agency requests comment on whether the
technical standards in 264.1084/265.1085 will address the risks
associated with vapor emissions from these units. EPA requests comment
on the proposed 1 ng/L TCDD TEQ concentration limit in wastewater that
triggers application of the air emission control requirements, and on
the testing and recordkeeping requirements for implementing this
standard. Specifically, EPA is requesting comment on comparing the
regulatory limit to a sample mean at the 95% upper confidence limit,
versus a maximum sample value with the sensitivity (as demonstrated by
the lower calibration standard), precision, and recovery (unless using
the isotope-dilution method) described in today's proposal.
In addition, we request comment on whether or not there are other
types of standards and/or other factors the Agency should consider in
setting standards for wastewater treatment units used to manage
chlorinated aliphatic wastewaters. The Agency is not reconsidering or
requesting comment on the wastewater treatment unit exemption and does
not intend to respond to any comments submitted regarding the
exemption.
b. How Is EPA Proposing to Regulate VCM-A Wastewaters?
EPA is proposing not to list as hazardous wastewaters generated
from the production of VCM using mercuric chloride catalyst in an
acetylene-based process. This wastestream already is defined as
hazardous waste due to the fact that it exhibits the toxicity
characteristic.
i. What Information Led EPA To Propose Not to List as Hazardous
Wastewaters From the VCM-A Process?
EPA knows of only one facility in the United States that operates
an acetylene-based VCM production process, which uses mercuric chloride
catalysts in the production of VCM. The management of spent mercuric
chloride catalyst used in the VCM-A production process results in the
generation of a wastewater containing mercuric chloride, as well as
vinyl chloride. The wastewater treatment system is operated in a batch
process fashion in tanks, and is designed to convert the mercuric
chloride present in the process wastewaters to an much less soluble
mercuric sulfide. The mercuric sulfide is precipitated during the
treatment process, dewatered, and collected for off-site disposal. The
remaining wastewaters are discharged directly under an NPDES permit.
Due to the fact that this wastewater is managed in a single, dedicated
wastewater treatment system associated with a unique production
process, and the presence of mercury in relatively high concentrations
(which is not found in other chlorinated aliphatic wastewaters), the
Agency decided to consider this wastestream separately in our
investigation of the wastes generated by the chlorinated aliphatic
hydrocarbons manufacturing industry.
According to the RCRA Section 3007 survey response, the facility
generates and discharges approximately 22,200 metric tons (5.86 million
gallons) of wastewater from the VCM-A process each year. The identified
constituents of concern in this wastestream include mercury and vinyl
chloride. In addition, dioxins are present in these wastewaters. EPA
analyzed one sample of this wastewater in 1996 in support of this
listing determination. The analytical results showed the wastewaters
contained 8.60 mg/L mercury, and 0.680 mg/L vinyl chloride. The
analytical results for the split sample taken by the facility were 6.78
mg/L mercury, and 1.38 mg/L vinyl chloride. The results exceed the
toxicity
[[Page 46506]]
characteristic regulatory levels of 0.2 mg/L for mercury and 0.2 mg/L
for vinyl chloride. Dioxins also were detected in the VCM-A
wastewaters, however, the concentration was several orders of magnitude
lower than levels found in other wastewaters generated from other
chlorinated aliphatic manufacturing processes (i.e., 0.0022 ng/L TEQ/
TCDD).
Based upon EPA's one record sample, this wastestream already is
identified as a hazardous waste due to the fact that the waste exhibits
the toxicity characteristic (TC). The constituents of significant
concern in the VCM-A wastewaters (i.e., mercury and vinyl chloride)
already are regulated under the TC, therefore, the TC adequately
defines this wastestream as hazardous. Further, the facility's
dedicated wastewater treatment system was designed and optimized
expressly for the removal of mercury from mercuric chloride catalysts
to comply with the Clean Water Act. In addition, given the fact that
EPA's record sample was over 40 times above the TC limit for mercury,
it is highly probable that these wasetwaters routinely contain levels
of mercury which cause this wastestream to be defined as
characteristically hazardous waste. As mentioned previously, the
criteria in 40 CFR 261.11 (a)(3) for evaluating whether or not a solid
waste is a hazardous waste provide that EPA should consider how the
waste (and potential risk) is affected by other regulatory programs
(i.e., 261.11(a)(3)(x)). In the case of the VCM-A wastewaters, EPA
notes that our decision to propose not to list this wastewater as
hazardous is based in large part on the fact that the waste already is
defined as a hazardous waste because it exhibits the toxicity
characteristic. We have, accordingly, determined that there is no
regulatory benefit in listing this wastewater as hazardous,
particularly when considering that the volume of wastewater generated
by the single facility using the acetylene-based VCM production process
is relatively small (22,200 metric tons annually) compared to the
volumes of wastewaters generated in other chlorinated aliphatic
wastewater treatment systems (11.5 million metric tons annually).
In addition, any risks associated with the management and disposal
(i.e., direct discharge) of the wastewaters are addressed by other
environmental regulations. With respect to the discharge of the
wastewater, the facility treats and discharges the wastewater in
compliance with the conditions of a NPDES permit. Regarding any air
emissions of vinyl chloride from these wastewaters, vinyl chloride is a
hazardous air pollutant, therefore the facility is subject to the
National Emissions Standards for Hazardous Air Pollutants (NESHAP)
requirements specific to vinyl chloride emissions (40 CFR Section
61.65), as well as the Hazardous Organic NESHAP for the synthetic and
organic chemical manufacturing industry sector (40 CFR Part 63, subpart
G) (59 FR 19468, April 22, 1994). For these reasons, the Agency is
proposing not to list VCM-A wastewaters as hazardous waste.
Sludges generated by the wastewater treatment process are disposed
of in an off-site hazardous waste (subtitle C) landfill. EPA conducted
a separate investigation of these sludges. The results of this
investigation and our listing determination for the VCM-A wastewater
treatment sludges are summarized in section III.E.3. further below.
2. EDC/VCM Wastewater Treatment Sludges
a. How Is EPA Proposing To Regulate EDC/VCM Wastewater Treatment
Sludges?
EPA is proposing to list as hazardous sludges generated from
treating wastewaters associated with the manufacture of ethylene
dichloride (EDC) and vinyl chloride monomer (VCM). This wastestream
meets the criteria set out at 40 CFR 261.11(a)(3) for listing a waste
as hazardous and is capable of posing a substantial present or
potential hazard to human health or the environment when managed in
land treatment units. The Agency identified risks of concern associated
with one management practice, on-site land treatment. In our risk
assessment of these wastes, the exposed individuals of concern were the
farmer, child of farmer, and the fisher receptors. The contaminants of
concern are dioxin and arsenic.
As discussed in section III.D.1 above, our analyses identified
health risks from the land treatment of the EDC/VCM wastewater
treatment sludges due to airborne releases and subsequent deposition
and food chain contamination from dioxin. Surface erosion due to runoff
also contributes to risk from dioxin. Marginal risks from arsenic were
identified for the land treatment unit groundwater ingestion exposure
pathway. We also modeled a landfill management scenario; our risk
assessment showed no significant risk from dioxin, and only marginal
risk from arsenic associated with the groundwater pathway.
b. What Information Led EPA To Propose To List as Hazardous EDC/VCM
Wastewater Treatment Sludges?
The results of the RCRA Section 3007 chlorinated aliphatic industry
survey show that approximately 104,606 metric tons of wastewater
treatment sludge is generated from the treatment of wastewaters at
chlorinated aliphatic plants that manufacture VCM and/or EDC. One
facility accounts for 74 percent of the total volume of wastewater
treatment sludge generated.33 Of the total volume of
wastewater treatment sludges generated at plants manufacturing EDC/VCM
and identified through the survey, 6,757 metric tons (6 percent)
currently are already defined as hazardous waste.
---------------------------------------------------------------------------
\33\ Only one (1) percent of the wastewaters at this facility
are generated from the manufacturing of EDC/VCM.
---------------------------------------------------------------------------
EDC/VCM wastewater treatment sludges are generated at 12
facilities. The Agency notes that these sludges are not always
generated from treating wastewaters produced exclusively from EDC and/
or VCM manufacturing processes. Rather, sludges are sometimes generated
in wastewater treatment systems that treat wastewaters from
manufacturing processes producing a variety of chlorinated aliphatic
and non-chlorinated aliphatic products. Wastewaters from multiple
processes are combined prior to wastewater treatment. The Agency points
out that the listing determination proposed today for EDC/VCM
wastewater treatment sludges affects the total quantity of the sludges
generated by a wastewater treatment system that accepts influent from
any process manufacturing EDC and/or VCM. EPA has made this clear by
including sludges from commingled EDC/VCM wastewater and other
wastewater within the scope of the listing, although EPA believes this
would have been the correct interpretation of the listing even absent
the clarifying language.
The management scenarios selected for risk assessment were chosen
based upon the waste management practices known to be practiced by the
chlorinated aliphatic industry for non-hazardous sludges. Based on
survey results, these practices are:
On-site land treatment (one facility),
On-site disposal in a non-hazardous landfill (two
facilities),
On-site co-disposal in a hazardous waste landfill (one
facility), and
Off-site disposal in a subtitle D landfill (7 facilities).
As explained earlier, EPA modeled risks from two management
scenarios,
[[Page 46507]]
an off-site non-hazardous municipal landfill, and a land treatment
unit. The management practices of most concern (landfills and land
treatment) were assessed for this waste. Other non-hazardous waste
management practices currently are not used by industry and would not
serve as an appropriate basis for listing the waste as hazardous. In
the case of the management practices employed by this industry, we are
confident that the risk estimates from modeling an off-site non-
hazardous waste landfill scenario also are representative of the
potential risks associated with the management of EDC/VCM wastewater
treatment sludges in on-site landfills. This is because information
provided in facility responses to the RCRA Section 3007 questionnaire
indicate that EDC/VCM wastewater treatment sludges are co-disposed with
other industrial non-hazardous wastes in on-site landfills, therefore
these units can be treated as off-site landfills (that receive a
variety of wastestreams) rather than as monofills (that receive only
one type of waste) with regard to the risk modeling approach employed.
Land treatment. The Agency's risk assessment of EDC/VCM wastewater
treatment sludge showed risks of concern for the land treatment
management scenario. The contaminant of greatest concern is dioxin. The
exposure routes of concern are airborne releases and surface erosion
from runoff which result in contamination of food products from nearby
agricultural operations. The sludges present a hazard due to the fact
that land treatment units are not covered and due to the potential
absence of runoff controls. Land treatment results in a high-end cancer
risk for the farmer of 2E-4 and a central tendency risk of 4E-6. EPA
also performed a Monte Carlo analysis, and the results showed a risk
for the farmer of 1E-4 at the 90th percentile, and 7E-6 at the 50th
percentile. The high-end deterministic risk falls within the risk range
for which there is a presumption for listing the waste as hazardous,
consistent with guidance the Agency has used for determining that a
waste is hazardous (see 59 FR at 66077), i.e., the risks associated
with management of EDC/VCM sludge in a land treatment unit are 1E-4 or
higher, and well above the 1E-5 listing benchmark. The probabilistic
results confirm that the high-end deterministic risk (2E-4) is above
the 90th percentile result (1E-4). The 1992 guidance (memorandum from
the then Deputy Administrator F. Henry Habicht ``Guidance on Risk
Characterization for Risk Managers and Risk Assessors'') states that
``[t]he `high end' of the risk distribution [generally the area of
concern for risk managers] is conceptually above the 90th percentile of
the actual (either measured or estimated) distribution. This conceptual
range is not meant to precisely define the limits of this descriptor,
but should be used by the assessor as a target range for characterizing
`high-end risk'.'' Therefore, a high-end estimate that falls within the
range (above the 90th percentile but still realistically on the
distribution) is a reasonable basis for a decision. Therefore, EDC/VCM
sludges managed in a land treatment unit pose risks that support a
proposed listing determination for these wastes.
As discussed previously, the risk assessment addresses nine of the
listing criteria in 40 CFR 261.11. EPA believes the risks resulting
from our analysis represent plausible management of EDC/VCM sludges
(261.11(a)(3)(vii)) using reasonable assumptions for management in land
treatment units. In addition, the risk analysis was developed using
actual analytical data.
Of lesser concern, but still within our discretionary risk range,
are the potential health effects associated with arsenic in EDC/VCM
wastewater treatment sludges that are managed in land treatment units.
We found that arsenic presents some risk from potential releases to
groundwater from the land treatment unit. For the arsenic groundwater
pathway, land treatment results in a high-end cancer risk of 1E-05 and
a central tendency risk of 8E-07. However, the predicted time period
for the peak arsenic concentration to reach a receptor well is 1,500
years. In addition, our modeled leachate concentrations for arsenic
result in predicted receptor well concentrations of 0.5 ppb (high end)
and 0.2 ppb (central tendency). By comparison, the average background
concentration of arsenic in rain derived from terrestrial air masses is
0.46 ppb.34 Therefore, EPA does not believe that the risk
from arsenic in this waste is significant, as discussed below.
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\34\ Andreae, M.O. 1980. Arsenic in Rain and the Atmospheric
Mass Balance of Arsenic. Journal of Geophysical Research. v.85, pp.
4512-4518, as cited in Welch, A.H., M.S. Lico, and J.L. Hughes.
1988. Arsenic in Ground Water of the Western United States. Ground
Water, v.26, n.3, pp. 333-347.
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Even though the high-end cancer risk from arsenic is within the
general action level risk range (i.e., 1E-04 to 1E-06), the central
tendency risk falls outside this range. Another factor that the Agency
considered when evaluating the potential risks from arsenic in this
wastestream is the significant period of time it is predicted to take
for the concentration of arsenic in a receptor well to reach the peak
concentration level (i.e., 1,500 years). Given these factors, the
Agency concludes that the risk posed from potential releases of arsenic
in this wastestream when managed in land treatment units is marginal,
and in itself does not warrant listing the waste as hazardous. The
Agency therefore is proposing to list EDC/VCM wastewater treatment
sludges based solely on the presence of dioxin and the potential risk
associated with dioxin when this waste is managed in land treatment
units. As outlined in the preamble to the Agency's proposed listing
determination for wastes generated by the Dyes and Pigments Industry,
listing determinations for wastestreams for which risks are calculated
to be 1E-04 or higher are considered to pose a substantial present or
potential hazard to human health and the environment and are listed as
hazardous.
Landfill. The Agency's risk assessment showed no significant risks
associated with dioxin, and only marginal risk associated with
potential groundwater releases of arsenic in the off-site landfill
scenario. The risk assessment showed a high-end cancer risk from
arsenic of 3E-05 and a central tendency risk of 9E-07. However, these
risks levels are associated with a peak arsenic concentration in a
receptor well that is predicted to occur only after a period of 8,800
years. Predicted high end arsenic concentration at a receptor well is
1.4 ppb and the central tendency arsenic concentration in a receptor
well is 0.2 ppb. This level of arsenic contamination is very close to
average background exposure levels for arsenic. As mentioned above, the
current average background concentration of arsenic in rain derived
from terrestrial air masses is 0.46 ppb. Average background exposure to
inorganic arsenic is 14 ug/day from food, and 5 to 7 ug/L from water.
EPA's modeling results indicate that the disposal of EDC/VCM sludge in
an unlined landfill could (over a period of 8,800 years) increase the
concentration of arsenic in groundwater in a downgradient well (102
meters from the landfill) by only 1.4 ug/L and would add approximately
2 ug/day of arsenic to the average daily exposure level (about 20 ug/
day) for the highly exposed individual. Actual potential level of risk
would be lower than those predicted by our modeling efforts, if the
sludges are disposed in lined landfills.
Given that the Agency's risk assessment indicates potential risk
within our discretionary range
[[Page 46508]]
associated with a peak arsenic concentration in a receptor well that is
predicted to occur only after a period of 8,800 years, and given the
absence of significant risk from any other constituents of concern, EPA
concludes that EDC/VCM wastewater treatment sludges do not pose a
significant risk when managed in landfills.
Based upon the Agency's findings that EDC/VCM wastewater treatment
sludges pose significant risks when managed in land treatment units but
pose no significant risks when managed in landfills, the Agency is
proposing a ``contingent management listing'' for this waste. EPA is
proposing to list EDC/VCM wastewater treatment sludges as hazardous,
unless the sludges are managed in landfills. Again, the Agency is
proposing this listing determination based upon the fact that our risk
assessment results for the land treatment unit scenario indicate a
level of risk of 2E-04, well above the 1E-5 risk level the Agency uses
as guidance in making listing determinations.
c. Why Is EPA Proposing a Contingent Management Approach as Most
Appropriate for EDC/VCM Wastewater Treatment Sludges?
The Agency's analysis of the risks associated with EDC/VCM
wastewater treatment sludges shows that one of the current waste
management practices (land treatment) results in significant risk while
the other primary management practice (disposal in subtitle D landfill)
shows little risk. Therefore, the Agency is proposing to list EDC/VCM
wastewater treatment sludges as EPA Hazardous Waste Number K174, unless
the sludges are managed in a subtitle C or subtitle D landfill. The
Agency believes that allowing the waste to continue to be managed under
a low risk management scenario (i.e., subtitle D landfilling) outside
of the subtitle C system achieves protection of human health and the
environment, and that little additional benefit would be gained by
requiring that all EDC/VCM wastewater treatment sludges be managed in
accordance with RCRA subtitle C management standards. Given the
Agency's finding that no significant risks are posed from managing EDC/
VCM wastewater treatment sludges in a landfill, the Agency sees no
reason to include sludges managed in this manner in the scope of the
hazardous waste listing. Additionally (and after consideration of the
predicted risk differential between land treatment and landfilling),
because only one facility identified in the RCRA Section 3007 Survey
employs land treatment for these wastes, this practice is somewhat
anomalous compared with land disposal. It does not make sense to apply
a traditional listing approach (i.e., list all wastes regardless of
management practice) based upon a practice occurring at one facility,
especially if a more tailored listing can prevent this risk.
A contingent management listing approach is within EPA's statutory
authority. See Military Toxics Project v. EPA, 146 F.3d 948 (D.C. Cir.
1998). The Agency believes that making a listing determination that is
tailored to specific waste management practices is particularly
appropriate under these circumstances, where the management practices
identified are clear and very easily distinguished (such as the
difference between land treatment and land disposal), and the
differences in risk presented by these practices are clearly defined.
In the case of EDC/VCM wastewater treatment sludges, EPA believes that
an opportunity exists to establish a conditional management listing for
these sludges that will reduce the risks associated with unsafe waste
management practices, while not imposing significant incremental costs
upon generators managing the wastes in a manner that does not pose
significant risk. While disposal of EDC/VCM wastewater treatment
sludges in land treatment units is projected to pose significant risks,
the disposal of these sludges in landfills does not result in
significant risks. This arises because the constituent of most concern,
dioxin/TCDD, is relatively immobile in groundwater. However, risks from
this constituent can be significant if the waste is managed in a manner
that does not control for airborne releases or surface erosion from
runoff, both of which are better controlled at landfills. Therefore,
EPA believes a contingent management listing for this waste is a
preferable and permissible alternative to simply listing all EDC/VCM
wastewater treatment sludges as hazardous wastes.
The Agency's proposed listing description for EDC/VCM wastewater
treatment sludges that will define this waste as hazardous unless the
waste is managed in a landfill is as follows:
K174 Wastewater treatment sludges from the production of ethylene
dichloride or vinyl chloride monomer, unless the sludges meet the
following conditions: (i) they are disposed of in a subtitle C or D
landfill licensed or permitted by the state or federal government;
(ii) they are not otherwise placed on the land prior to final
disposal; and (iii) the generator maintains documentation
demonstrating that the waste was either disposed of in an on-site
landfill or consigned to a transporter or disposal facility that
provided a written commitment to dispose of the waste in an off-site
landfill. Respondents in any action brought to enforce the
requirements of subtitle C must, upon a showing by the government
that the respondent managed wastewater treatment sludges from the
production of vinyl chloride monomer or ethylene dichloride,
demonstrate that they meet the terms of the exclusion set forth
above. In doing so, they must provide appropriate documentation
(e.g., contracts between the generator and the landfill owner/
operator, invoices documenting delivery of waste to landfill, etc.)
that the terms of the exclusion were met.
d. How Will This Contingent Management Listing Be Implemented?
Under this proposed listing, EDC/VCM wastewater treatment sludges
will be hazardous wastes if managed by any method except disposal in a
landfill. EPA has a clear interest in ensuring that these sludges are
in fact disposed in a landfill, or else they would be listed hazardous
waste at the point of generation. The Agency also has an interest in
making sure that accurate records are kept to facilitate enforcement.
The Agency notes that based on the RCRA Section 3007 questionnaire
results (which surveyed the universe of chlorinated aliphatics
production facilities in the United States), the predominant management
practice used for these wastes is disposal in a landfill, while one
facility currently uses a land treatment facility. It is difficult for
EPA to foresee a change in this well-established management practice.
Therefore the Agency believes it is unlikely that these sludges will be
sent to any type of facility other than a landfill, particularly if the
approach proposed in today's rule is promulgated. Generators who choose
to manage these sludges at non-landfill facilities must define their
sludges as listed hazardous waste at the point of generation and manage
them accordingly.
The Agency also is restricting the placement of EDC/VCM wastewater
treatment sludges on the ground prior to
[[Page 46509]]
their being disposed in a landfill (e.g., storage in waste piles,
spills). EPA wants to ensure that these wastes, which are clearly
capable of presenting unacceptable risk if improperly managed, are
managed only in the manner found to be protective of human health and
the environment.
Generators, and other parties involved in the management of EDC/VCM
wastewater treatment sludges, claiming that their wastes fall outside
the scope of the hazardous waste listing must be able to demonstrate
that sludges excluded from the listing description are being managed in
accordance with all of the conditions for being excluded from the
listing. This means that parties claiming the waste falls outside the
scope of subtitle C must be able to demonstrate that (1) previously
generated and managed waste (which is being claimed as not meeting the
K174 listing) was disposed of in a landfill; and (2) waste currently
being managed is not being stored, or otherwise managed, on the land
(e.g., landfarms, waste piles) as well as demonstrate that the waste
will be disposed of in a landfill (e.g., have a contract in place with
a landfill owner/operator that specifies intent to manage EDC/VCM
sludges at the landfill facility). To further clarify how today's
proposed approach would be implemented, below we describe these two
distinct situations where a listing determination will be made under
this proposed approach.
i. EDC/VCM Sludges Sent Off-Site
Under the proposed contingent management listing for K174, EDC/VCM
sludges that already have been shipped from the generator facility to a
subtitle C or subtitle D landfill were never a listed hazardous waste.
In this instance, should a question arise as to the status of sludges
previous shipped off-site, the implementing agency would look to
indications such as contracts between the generator and the landfill
owner/operator, invoices showing waste was delivered to a specific
landfill, and other documents that clearly show the waste was
transferred to a subtitle C or subtitle D landfill.
ii. EDC/VCM Sludges at Generator Site
In this situation, determining whether or not an EDC/VCM sludge
meets the proposed K174 listing would be done in a prospective manner,
not unlike many of the existing regulatory exclusions from the
definition of solid waste (where determinations of whether or not a
material is a waste are often based upon how the waste will be managed,
i.e., recycled. See, for example, requirements at 40 CFR 261.2, Table
1, and 261.4(b)). Under the existing generator requirements in 40 CFR
Part 262, generators of solid waste must determine whether the waste is
a listed hazardous waste (40 CFR 262.11(b)). Determinations made by
generators regarding whether their EDC/VCM sludges are listed (where
these sludges have not yet been disposed of off site in an appropriate
landfill) will be made by virtue of where the waste will be sent. In
situations where the implementing agency is questioning any claims by
the generator of the non-listed status of sludges being stored on site,
the generator should be able to show that there is an agreement already
in place with a transporter and/or landfill indicating that these
sludges will be delivered to a landfill. It is the EPA's experience
that wastes cannot usually be shipped to a commercial landfill without
first establishing a relationship with that landfill, where factors
such as the amount of waste, the frequency of shipments, the physical
and chemical make up of the waste, etc., are agreed upon before the
waste ever arrives at the landfill.
In the case of generators who manage EDC/VCM in on-site landfills,
the Agency requests comment on the types of records or documentation
that may be used to verify or document that the waste is managed in the
on-site landfill and not managed in a land treatment unit.
The Agency notes that it is not our intent to condition the
regulatory status of the waste upon a recordkeeping or paperwork
requirement. The Agency believes that the ability to demonstrate the
commitment to dispose of the waste in a landfill is necessary to ensure
the waste falls outside the scope of the listing. We do not believe
that any specific recordkeeping requirement (e.g., the completion and
retention of a specific form) is necessary to make this demonstration.
We believe that documentation of previous landfilling of the waste and
a demonstration of a commitment to dispose of currently generated waste
in a landfill may be made by several means. EPA is requesting comment
on the types of records and/or documentation normally kept by
generators and/or disposal facility owner/operators that may be used to
make such demonstrations (see section III.E.2.f. below).
EDC/VCM wastewater treatment sludges that are not listed hazardous
waste due to contingent management will be considered nonhazardous from
their point of generation. As a result, such sludges will not be
subject to RCRA subtitle C management requirements for generation,
transport, or disposal (including the land disposal restrictions), if
the waste is destined for disposal in a landfill (and the generator can
demonstrate such intention).
Of course, if the waste is not disposed of in such a unit, then the
exemption would no longer apply and the waste would have to be managed
in compliance with subtitle C management requirements, from the point
of generation. In other words, if the Agency finds that the waste is
disposed of in a unit other than a subtitle C or D landfill, the Agency
may cite the generator of the waste as being out of compliance with all
applicable subtitle C management requirements. The Agency also points
out that should EDC/VCM wastewater treatment sludges meet the listing
description for another hazardous waste listing, or if the wastewater
treatment sludges exhibit one or more of the characteristics of
hazardous waste, the sludges must be managed as hazardous wastes and
are not exempt from regulation under today's listing determination,
regardless of how the sludges are managed.
e. What Specific Comments Is EPA Requesting on Implementation of the
Contingent Management Listing Approach?
The Agency requests comments on this proposed contingent management
listing approach, and may make changes to the implementation approach
based on comments received. EPA notes that this contingent management
approach necessitates that the Agency have the ability to confirm
whether or not wastes claimed to fall outside the scope of the listing
description are disposed of in a landfill as required by the proposed
listing determination. As a result, some type of documentation or
demonstration that the waste actually is disposed of in a landfill (or
will be disposed of this way) is appropriate.
EPA is proposing that generators be able to provide documentation
that waste previously generated (for which the claim is made that the
waste is not K174) was disposed in an on-site landfill or transported
to and received by an off-site landfill. In addition, a generator must
be able to demonstrate that waste currently present at the generator's
facility will be disposed in an on-site or off-site landfill, and that
the waste will not be stored, or otherwise managed, on the land prior
to disposal in a landfill. Appropriate types of documentation that may
fulfill these requirements may include: contracts between a generator
and a landfill owner/operator, invoices documenting that the waste was
transported to and received by a landfill facility, bills of
[[Page 46510]]
lading or other shipping papers that clearly indicate the type and
quantity of waste shipped off-site, the date of shipment, the name and
address of the landfill receiving the waste, and the date the waste was
received by the landfill.
EPA requests comment on the type of records, documentation, and
demonstrations that may be adequate for determining compliance with the
contingent management listing. EPA requests comment on what type of
internal records may be kept by solid waste generators that may
demonstrate intended management of the waste and whether such records
are adequate for demonstrating compliance with the contingent
management conditions for exclusion from the hazardous waste listing.
EPA also requests comment on its proposal that waste that does not meet
the terms of the conditional listing is hazardous from the point of
generation.
3. VCM-A Wastewater Treatment Sludges
a. Is EPA Proposing To Regulate VCM-A Wastewater Treatment Sludges?
Yes, EPA is proposing to list as hazardous wastewater treatment
sludge from the production of vinyl chloride monomer using mercuric
chloride catalyst in an acetylene-based process (VCM-A). The sludge is
generated at one facility as a result of treating water running off an
area where spent mercury catalysts are removed from the VCM-A
production process. The Agency has concluded that the waste meets the
listing criteria in 40 CFR 261.11(a)(3) and is capable of posing a
substantial present or potential hazard to human health and the
environment if mismanaged. For reasons explained in more detail below,
EPA is proposing two alternative approaches for listing this waste as
hazardous. The Agency is requesting comment on both proposed
approaches.
b. What Information Led EPA To Propose To List as Hazardous VCM-A
Wastewater Treatment Sludges?
i. Background
As previously described in today's proposed rule, the manufacture
of vinyl chloride monomer in an acetylene-based process using mercuric
chloride catalysts generates non-process wastewaters as a result of
precipitation runoff in the production area, as well as from using
water to remove spent catalyst from the reactors. Because of its high
mercuric chloride content, this wastewater is collected and treated in
a dedicated non-biological treatment system that uses sodium sulfide to
convert the mercuric chloride to mercuric sulfide, which precipitates
as a sludge and is dewatered to form a filter cake. This treatment
system is operated in a batch-process fashion, and treated effluent is
discharged under the facility's NPDES permit. EPA knows of only one
facility in the United States that operates an acetylene-based VCM
production process. According to the facility's response to the RCRA
Section 3007 survey, this waste was sent to a permitted hazardous waste
landfill for disposal in 1996. Other information provided by the
facility in response to a separate RCRA Section 3007 request from EPA
indicates this waste was sent to the same permitted hazardous waste
landfill from 1990 to 1994 as well. The facility generates
approximately 120 metric tons of VCM-A wastewater treatment sludge per
year.
ii. Analytical Results
EPA analyzed one sample of this sludge in 1996 in support of this
listing determination. The analytical results showed the sludge
contained 9,200 mg/kg total mercury, and 0.26 mg/L in leachate using
TCLP. The results for a split sample analyzed by the facility were
17,700 ppm total mercury, and the TCLP result was 0.654 mg/L. These
results indicate a very high total mercury concentration (approximately
one to two percent of the waste is mercury), and the TCLP results
exceed the regulatory level for the mercury toxicity characteristic of
0.2 mg/L. Data generated by EPA in support of a treatability study on
this particular waste showed a total mercury concentration (in aliquots
of a single sample) ranging from approximately 3,000 to 9,000 mg/kg,
and TCLP results were all below the regulatory limit.35
Other data available to EPA from the facility indicate that
approximately 20 percent of the tested samples exceed the regulatory
level for mercury 36.
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\35\ Paul Bishop, Renee A. Rauche, Linda A. Rieser, Markram T.
Suidan, and Jain Zhang; ``Stabilization and Testing of Mercury
Containing Wastes,'' Draft, Department of Civil and Environmental
Engineering, University of Cincinnati, March 31, 1999. Please note
that this is a draft EPA document not yet peer reviewed. Also, data
within the report is still undergoing QA/QC review, and the text,
data, and conclusions in the report may change before the document
is finalized.
\36\ Summary of Mercury TCLP Data on VCM-A Sludge from Borden
Chemicals and Plastics, EPA July 1999.
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iii. Assessment of Potential Risk
EPA's quantitative analysis of the potential groundwater risks
posed by this waste assumes waste disposal in an unlined landfill. The
Agency is making use of previously conducted groundwater modeling and
risk analyses for the proposed Hazardous Waste Identification Rule (60
FR 66344, December 21, 1995) that resulted in an estimated dilution and
attenuation factor (DAF) for mercury of 40. Using this DAF and the
mercury leachate concentration of the VCM-A sludge analyzed by EPA
(0.26 mg/L), the expected concentration of mercury at a modeled
receptor well (after a release to groundwater from an unlined landfill)
exceeds the maximum contaminant level (MCL) for mercury (0.002 mg/L) by
a factor of three. Using the mercury leachate concentration from the
facility's split sample (0.654 mg/L), the mercury MCL would be exceeded
at a modeled receptor well by a factor of eight.
EPA is unable to quantitatively assess the potential risk this
waste poses when disposed in a subtitle C landfill without prior
treatment. However, we qualitatively considered the risk associated
with such a management scenario. There is considerable uncertainty
about the performance of engineered landfills. In the near term,
especially at regulated subtitle C landfills, there are quality
assurance controls to reduce the likelihood of significant material,
installation, or facility operation errors that could degrade
performance of the engineered systems. In addition, such landfills have
ground water monitoring and leachate management controls to further
reduce the chances of significant ground water risk. However, in the
long-term, there is considerable uncertainty as to how well engineered
systems will operate and whether there will continue to be long-term
care and maintenance after the regulatory post-closure period ends. EPA
can only qualitatively consider the potential long-term risk of wastes
in subtitle C landfills. However, we considered the above mentioned
uncertainties, along with the quantitative estimates of potential risk
in unlined landfills, when assessing the potential risks of managing
untreated wastes in a subtitle C landfill, such as VCM-A sludges that
contain persistent constituents such as mercury.
iv. Rationale for Proposed Hazardous Waste Listing Determination
EPA is proposing two rationales to ``list'' this waste as
hazardous, both of which lead the Agency to conclude we should propose
to list this wastestream as hazardous waste. First, EPA believes it is
plausible that this waste may be mismanaged and disposed of in an
unlined and uncovered landfill and that it is capable of posing a
substantial
[[Page 46511]]
hazard if so managed. Second, based upon information EPA has, including
information on liner performance and the mobility of mercury under
certain pH conditions, EPA believes that even when disposed of in a
landfill that is compliant with Subtitle C landfill standards, this
waste is likely to leach significant quantities and concentrations of
mercury that long-term degradation of the landfill's leachate control
systems (especially after post-closure care has ended) would plausibly
cause an unacceptable release of mercury into groundwater and has the
potential to pose a substantial hazard when this waste is so managed
without improved prior treatment. EPA requests comment on the basis for
the rationales described above, both for the disposal scenario in an
unlined landfill, and the disposal scenario in a landfill compliant
with subtitle C landfill standards.
The Agency's analysis of potential risk indicates that disposal of
the VCM-A sludge in an unlined landfill may result in risks due to the
migration of mercury in groundwater to a receptor well in
concentrations that exceed the MCL for this constituent. The Agency
notes that the single facility generating this waste reports managing
the waste by disposing of it in a subtitle C landfill for certain
years. Therefore, a simple conclusion may be to dismiss the potential
risk for the groundwater pathway (assuming it continues to go to a
subtitle C landfill) due to the presence of a landfill liner and
leachate collection. In addition, (as mentioned previously) the mercury
in the waste is in the form of mercuric sulfide, which generally is
found to be a relatively insoluble form of mercury (indicated by only a
relatively small percentage of the total mercury content of the waste
leaching under the TCLP). However, data recently collected by the
Agency and preliminary results from the analysis of this waste indicate
that this waste may not behave in the same manner (in terms of the
mobility of mercury in sulfidic form) in all environments. As discussed
briefly below (and further in the Land Disposal Restrictions, Section
V.F.), available data indicate that although the mercury in the VCM-A
sludge remains relatively immobile at pH levels of 6 or lower, higher
pH conditions will result in mercury mobilizing to the aqueous
phase.37
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\37\ H. Lawrence Clever, Susan A. Johnson, and M. elizabeth
Derrick, The Solubility of Mercury and Some Sparingly Soluble
Mercury Salts in Water and Aqueous Electrolyte Solutions, J. Phys.
Chem. Ref. Data, Vol. 14, No. 3, 1985, page 652.
---------------------------------------------------------------------------
Using data from a collected sample of the VCM-A wastewater
treatment sludge, constant pH leaching tests were conducted on the
waste sample to determine the effect pH has on the stability of the
waste. The preliminary results of the constant pH leaching tests showed
that mercury leachate concentrations were lower in samples leached at a
pH of 6.0 or lower (e.g., 0.00582 mg/L at pH=6 after 24 hours),
compared with concentrations at higher pH conditions. The same sample
leached at pH of 10 produced a significantly higher mercury leachate
concentration of 1.63 mg/L after 24 hours.38
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\38\ Paul Bishop, op. cit., p. 14.
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Information obtained by EPA on the pH levels of actual leachate
collected from the landfill cell in which the VCM-A wastewater
treatment sludge currently is disposed show that the pH is greater than
9.39 If this pH value is indeed indicative of the disposal
environment for this waste, then based upon the pH relationship
identified in the preliminary results of constant pH leach tests
described above, one would predict that the mercury would be
significantly mobilized under the disposal environment actually being
used for this waste.
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\39\ E-mail communication to John Austin, U.S. EPA, from Mitch
Hahn, Waste Management Corporation, April 14, 1999.
---------------------------------------------------------------------------
In summary, although the waste is disposed in a subtitle C
landfill, the fact that the mercury in the waste may mobilize at pH
levels greater than 6 means that the leach test results may under
predict concentrations in leachate. In case of significant leachate
contamination, the landfill liner may be the only guard against the
release of mercury to the environment (due to the fact that the waste
is not stable in this landfill disposal scenario). Should the liner
fail, mercury present in the leachate would be released to the
environment.
EPA acknowledges that a liner/leachate collection system in a
subtitle C unit serves to contain and remove waste leachate and
provides important environmental protection. However, EPA recognizes
that there is inherent uncertainty in such systems, and it believes
that the purpose of the RCRA hazardous waste treatment requirements (as
expressed by Congress) is to reduce the uncertainty inherent in
engineered containment approaches. EPA believes that waste containment
systems will tend to degrade with time. Eventually, synthetic liners
will degrade and leachate collection systems will cease operation. As
put forth in the proposed Liner and Leak Detection Rule (52 FR 20218,
May 29, 1987), no liner can be expected to remain impervious forever.
Properly installed double liner and leachate collection systems,
together with final covers placed at closure, will substantially reduce
releases during the operating life and post-closure care period.
However, these technologies may not always reduce the longer-term risk
for landfills to acceptable levels for persistent, mobile, and highly
toxic compounds. This is because the containment system may not prevent
leachate release from the landfill indefinitely, for example after the
post-closure period, when active maintenance of the cap and leachate
collection system may be reduced or may end. The Agency has found that
treatment of the waste under the LDR standards of RCRA subtitle C will
significantly reduce potential risks from the disposal of this waste
over the long term. This is particularly important for a constituent
such as mercury, that is persistent and does not degrade. Treatment in
accordance with prescribed BDAT can reduce the possibility that
leachable mercury is available for release to the environment. Again, a
liner/leachate collection system in a subtitle C unit is expected to
contain waste leachate and lessen the risk while such a system is
intact. However, even assuming a low probability of failure, because
the TCLP may be significantly under predicting leachability for this
waste in this subtitle C disposal scenario, there may still be a
release of mercury that results in an exceedance of the MCL. While
there are uncertainties in this assessment, it still illustrates that
the mercury concentrations in the receptor well may be close to, and
could even be higher than the MCL. Given the well-documented toxicity
and persistence of mercury, the potential for greater mobility of
mercury from this particular waste in a subtitle C landfill (than
predicted by the TCLP), and the uncertainties associated with
engineered landfills over the long-term--as reflected in statutory
language regarding treatment requirements--EPA believes that the
disposal of this waste, untreated, in a subtitle C landfill may not be
protective and therefore may warrant listing the waste as hazardous.
In EPA's view, it may violate Congressional intent to allow a waste
that the Agency otherwise would list as hazardous (absent the fact that
the waste is managed untreated in a Subtitle C landfill) to be disposed
in a hazardous waste landfill under conditions that may result in the
hazardous constituents
[[Page 46512]]
in the waste leaching from the waste (due to the high pH of the
landfill environment). Congress clearly expressed its intent that the
Agency is not to place excessive reliance or confidence in landfill
design and liners for problematic wastes. In the Hazardous and Solid
Waste Amendments (HSWA) of 1984, Congress explicitly added as one of
the ``findings'' to RCRA that ``land disposal facilities are not
capable of assuring long-term containment of certain hazardous wastes''
and that ``reliance on land disposal should be minimized or
eliminated.'' 40 As a result of this finding, and others,
Congress added the land disposal restriction program to RCRA, which
significantly restricts land disposal of hazardous wastes and provided
in section 3004(m) the mandate that EPA develop treatment standards for
``diminishing the toxicity of wastes or substantially reducing the
likelihood of migration of hazardous constituents from the waste so
that short-term and long-term threats to human health and the
environment are minimized.'' In addition, the legislative history to
RCRA section 3004(m) states that this section ``makes Congressional
intent clear that land disposal without prior treatment of these wastes
with significant concentrations of highly persistent, bioaccumulative
constituents is not protective of human health and the environment.''
(130 Cong. Rec. S 9178; daily ed. July 25, 1984). Were we to propose a
no list determination for this waste based solely upon the fact that
this waste currently is disposed in a subtitle C landfill--ignoring the
high levels of total mercury in the waste, its potential for leaching
(at high pH), and the likely benefits of treatment--we would be
bypassing Congressional intent that wastes be treated to reduce
toxicity and/or migration of hazardous constituents before final
disposal.
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\40\ RCRA section 1002(b)(7), 42 U.S.C. 6902(b)(7).
---------------------------------------------------------------------------
EPA views the statute and legislative history as sufficient
justification to evaluate in a listing determination all risks of land
disposal, including in appropriate cases problems that might be
associated with voluntary disposal of untreated wastes in permitted
subtitle C facilities. This is particularly true where risks presented
by a waste will be high if releases occur, if the waste is highly
persistent, and treatment of the waste under subtitle C would
significantly reduce these risks. In the case of the VCM-A wastewater
treatment sludges, the potential risks presented by the high content of
mercury in the waste if a release should occur, warrants the imposition
of treatment standards in accordance with Congress's intent. Although
the generator currently sends VCM-A wastewater treatment sludges to a
lined subtitle C landfill facility, we believe that substantial risks
are plausible, given the possibility of eventual landfill degradation
or failure. The estimated risks due to migration from an unlined
landfill provide an indication of the potential risks that will occur
if mercury is released from the lined landfill due to failure of the
unit to contain the waste leachate over time.
Absent a hazardous waste listing, the Agency has no mechanism for
requiring that the waste be treated prior to disposal to ensure that
the mercury in the waste does not leach from the waste to the
surrounding environment (and hence provide some protection of human
health and the environment in the event of a liner failure).
Furthermore, the Agency has little assurance that the waste will
continue to be managed in a subtitle C landfill.
Listing a waste as hazardous provides a level of certainty with
regard to the management and stewardship of a waste as well. Given the
quantity of mercury contained in the VCM-A wastewater treatment sludge
and the potential solubility of this large quantity of mercury, the
Agency tentatively concludes that it is appropriate that the waste be
managed in accordance with the ``cradle-to-grave'' management system
established under RCRA Subtitle C. By listing this waste as hazardous,
EPA and the general public are afforded a greater level of certainty
with respect to the manner in which the waste must be managed. It will
have to be accumulated and stored in closed containers, sent off-site
for treatment and disposal within a relatively short time of the time
it was generated, transported by a registered hazardous waste
transporter and accompanied by a manifest, and treated and disposed at
facilities permitted to handle hazardous wastes.
The Agency bases its listing determinations on an evaluation of
risks from plausible management practices. For the reasons just
described, EPA believes that disposal of untreated VCM-A sludge in a
subtitle C landfill represents one plausible management scenario and
that this scenario could lead to significant problems. Equally
important, the Agency questions whether the current waste management
practices are the only practices that will be employed by the facility
in the future. That is, the Agency believes other management practices
are plausible. First, information available to the Agency documents
only that the facility has sent VCM-A wastewater treatment sludges to a
subtitle C landfill for disposal for some periods after 1990.
Specifically, information provided by the facility in response to a
specific RCRA Section 3007 request from EPA indicates this waste was
sent to a subtitle C landfill from 1990 to 1994; and according to the
facility's response to the RCRA Section 3007 survey, this waste was
sent to a permitted hazardous waste landfill for disposal in 1996. In
addition, we have no information with regard to the disposal of the
waste prior to 1990. The Agency does know that the facility had as many
as 800 drums of the mercuric sulfide sludge stored on site in 1985;
however the Agency has no information with regard to the ultimate
management of the waste.41 Given the fact that the Agency
does not have a complete record of how the VCM-A sludge was managed in
the past, the Agency believes that it is reasonable to assume that the
VCM-A sludge may be managed in an non-subtitle C landfill in the
future.
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\41\ ``Reclassification Petition'' submitted to Louisiana
Department of Environmental Quality, Hazardous Waste Division, by
Borden Chemical, September, 1987, p. III-2.
---------------------------------------------------------------------------
Therefore, for the purposes of assessing potential risk, the Agency
believes a plausible mismanagement scenario can also include an unlined
landfill, the scenario in which the Agency's risk analysis indicates a
potential for the concentration of mercury at a modeled receptor well
to be as much as eight times higher than the MCL for mercury (based
upon the TCLP results and a DAF of 40).
Our assessment includes predicted exceedances of the MCL (based
upon the record sample EPA collected) assuming disposal in an unlined
landfill; and a qualitative consideration of the possible risks when
disposed in a subtitle C landfill without better treatment. Although
risk analyses provide one of the principal bases for a listing
determination, estimates of risk levels do not represent the sole basis
for a listing determination. Other factors generally are considered in
making a listing decision. In fact, the Agency's listing decision
policy uses a ``weight-of-evidence'' approach in which calculated risk
information is a single key factor. Available risk values are assessed
with all other data available to determine whether a waste is or is not
a hazardous waste (see the discussion of EPA's hazardous waste listing
determination policy in the proposed listing for wastes generated by
the dye and pigment industries at 59 FR 66073, December 22, 1994). In
our decision to propose to list this sludge as hazardous,
[[Page 46513]]
the Agency considered several factors, including the extensive
documentation on the toxicity of mercury, as well as the other criteria
listed in 261.11(a)(3) to arrive at a listing determination, as further
summarized below.
Mercury has been identified by several different governmental
agencies, including EPA, the Agency for Toxic Substances and Disease
Registry (ATSDR), the Food and Drug Administration (FDA), and the
Occupational Safety and Health Administration (OSHA), as a significant
human toxicant. Each of these Agency's has developed regulations,
guidelines, and/or standards to protect people from the serious
potential health effects of exposure to mercury. In addition, it also
is well documented that mercury is persistent in the environment, does
not degrade, and bioaccumulates in wildlife, particularly fish. Agency
studies, including the recently published Mercury Study Report to
Congress 42 have documented the neurotoxicity of mercury and
the potential adverse human health and environmental effects that may
result from the release of mercury to the environment. In addition,
ATSDR has published a toxicological profile for mercury which examines,
summarizes and interprets toxicological information and epidemiological
evaluations on mercury.43 Research conducted by both EPA and
ATSDR provides documentation of the highly toxic effects of human
exposure to mercury. Human consumption of highly-contaminated food can
produce overt mercury neurotoxicity. Neurotoxic effects from mercury
contamination range from subtle decrements in motor skills and sensory
ability at comparatively low doses to tremors, inability to walk,
convulsions and death at extremely high exposures. Human consumption of
fish or grain contaminated with high levels of mercury can result in
permanent damage to the brain, kidneys and developing fetuses. Adverse
effects of mercury on fish include death, reduced reproductive success,
impaired growth and development and behavioral abnormalities. Exposure
to mercury also can cause adverse effects in plants, birds and mammals.
The extent and availability of toxicity assessments for mercury is
relatively extensive (see EPA's ``Mercury Study Report to Congress''
and/or EPA's ``Action Plan for Mercury'') 44. Certainty with
regard to the potential risks to human health and the environment from
exposure to mercury is well documented. Mercury presents significant
human health threats when released to the environment.
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\42\ U.S. Environmental Protection Agency (1997), EPA-452-R-97-
003-009.
\43\ ``Toxicological Profile for Mercury,'' ATSDR, April, 1999;
http://www.atsdr.cdc.gov/press/ma990419.html.
\44\ ``Mercury Study Report to Congress,'' volumes I-VIII, EPA-
452/R-97-003, December 1997; and EPA Action Plan for Mercury
(Atttachment 1 to ``An Agency-Wide Multi-media Strategy for Priority
PBT Pollutants''), http://www.epa.gov/ttnuatw1/112nmerc/
mercury.html.
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Wastewater treatment sludges from the VCM-A process using mercuric
chloride catalyst contain significant levels of total mercury. As
mentioned previously, approximately 120 metric tons of the sludge,
containing about one percent (or 1 MT) of mercury, is generated per
year at a single facility. One metric ton of mercury is approximately
20 times as much mercury as is received typically by a single municipal
solid waste landfill from all sources in one year. EPA also notes that
in this particular case, we believe the mercury is likely to be
significantly leachable at pH levels of a typical hazardous waste
landfill. The Agency considers this quantity of potentially leachable
mercury generated from a single facility and disposed of off-site to be
significant. As outlined in the Draft EPA Action Plan for Mercury
45, and EPA's Waste Minimization National Plan
46, it is important to the protection of human health and
the environment that all anthropogenic sources of mercury emissions to
the environment be minimized. Given the inherent risks associated with
mercury, EPA believes it is necessary to ensure, to the greatest extent
possible, that wastes containing significant quantities of mercury are
safely managed and to guard against potential mismanagement.
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\45\ Attachment to A Multimedia Strategy for Priority
Persistent, Bioaccumulative, and Toxic (PBT) Pollutants, November
16, 1998, EPA 742/D98/001, http://www.epa.gov/opptintr/pbt/
pbtstrat.htm.
\46\ Waste Minimization National Plan, US EPA, 1994, EPA530-R-
94-045, http://www.epa.gov/rgytgrnj/specinit/p2/volprog/wm.htm.
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Upon consideration of the factors enumerated in 40 CFR 261.11(a)(3)
and those summarized in the 1994 Dyes and Pigments Proposed Rule for
making a hazardous waste listing determination, EPA made the following
conclusions with respect to this waste. In terms of waste
characterization, data available on this waste indicate with relative
consistency that the waste contains a significant amount of total
mercury, regardless of variation in pH and leachable mercury.
Furthermore, in this particular case, we believe that the mercury is
likely to be more leachable than the TCLP test indicates. It is well
documented that mercury is a human toxicant. Mercury is persistent in
the environment, does not degrade, and bioaccumulates in wildlife,
particularly fish. These conclusions correspond to the listing factors
at 40 CFR Sections 261.11(a)(3)(i), (iv), (v), and (vi), respectively.
After considering the listing factors in 261.11(a)(3), and in
particular the factors at 261.11(a)(3)(i)-(vi) (which include potential
risks to groundwater from unregulated disposal of this waste, the fact
that mercury is a human toxicant, is persistent in the environment,
does not degrade, bioaccumulates in wildlife, and is present in very
high concentrations in this waste), as well as several of the
``additional factors'' listed in the 1994 Proposed Rule for Wastes
Generated by the Dyes and Pigments Industry, and taking into account
the Agency's overall goals to reduce releases of mercury to the
environment, EPA is proposing to list this waste as hazardous. The
proposed listing description is shown below.
K175 Wastewater treatment sludges from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-
based process.
The proposed listing of VCM-A wastewater treatment sludges, which
contain substantial amounts of total mercury is, in effect, an
extension of the Agency's policy with regard to mercury emissions. The
Agency believes that listing these wastewater treatment sludges as
hazardous will provide incentive for the facility to find ways to
reduce the overall quantity of mercury-containing VCM-A sludges
generated. EPA believes there may be opportunities for this type of
reduction through improved catalyst handling practices. Improved
handling practices may result in a reduction in the amount mercuric
chloride released in and around the VCM-A process area where it becomes
available for introduction to the wastewater treatment system. In turn,
this reduction would result in an overall decrease in the amount of
mercury available for potential release to the environment.
Once a waste is listed as a hazardous waste, the waste is
prohibited from land disposal unless it is treated in compliance with
treatment standards established under the RCRA land disposal
restrictions standards program. The mercuric sulfide sludge generated
from the VCM-A production process is unique in that this waste contains
a very high amount of total mercury, and the
[[Page 46514]]
mercury is present in the waste in a relatively insoluble form as
measured using the TCLP. However, the preliminary findings of the EPA/
ORD study described above suggest that variability in the pH of the
waste as generated, and higher pH conditions potentially encountered in
the disposal unit where this waste is managed, can affect the stability
of the VCM-A sludge when disposed in a subtitle C landfill. The Agency,
therefore, is proposing specific LDR treatment standards for this waste
to minimize the potential release of mercury to the environment from
this waste. A discussion of the proposed BDAT treatment standards for
newly listed VCM-A wastes is provided later in this notice.
c. What Alternative Is EPA Considering for a Proposed Listing
Determination?
i. Summary of Alternative Listing Option
The alternative listing option EPA is proposing today is to list
the VCM-A wastewater treatment sludges as hazardous waste, unless the
waste is disposed in a subtitle C landfill. In addition, under this
alternative option, VCM-A wastewater treatment sludges that exhibit the
toxicity characteristic for mercury will be listed as hazardous. In
other words, this waste will not meet the proposed K175 listing
description, and therefore will not be listed hazardous waste from the
point of generation, so long as it is disposed in a subtitle C
landfill, and it does not exhibit the TC for mercury.
ii. Rationale for Alternative Listing Option
As described earlier, EPA believes that the VCM-A sludge meets the
criteria for being listed as a hazardous waste, principally due to the
high concentration of mercury, a highly toxic constituent, in this
waste. Available information indicates that the direct disposal of
untreated VCM-A sludge in a subtitle C landfill may result in a marked
increase in the mobility of mercury, and that, should the liner system
ultimately degrade, this mercury can be released to groundwater and
potentially reach a receptor well in concentrations at the MCL. Also,
the Agency believes that disposal of these wastes in an unlined
landfill is a plausible mismanagement scenario, which would result in
exceedances of the MCL by up to a factor of eight. The Agency is
seeking comment on these tentative conclusions and this proposed
listing determination. Should the Agency receive data or other
information on the conclusions drawn by the Agency with regard to the
management of the waste and the behavior of this waste in the
environment, particularly with regard to the potential for the mercury
in the waste to leach under conditions of high pH levels, the Agency
will consider alternative approaches. For example, if direct disposal
of untreated VCM-A sludge in a subtitle C landfill can be shown to be
protective without further treatment of this waste, due to the relative
insolubility of mercuric sulfide or expected long-term performance of
subtitle C systems, EPA will consider a conditional listing of VCM-A.
Such an conditional listing would specify that the wastewater treatment
sludges are listed only if the waste is not disposed in a subtitle C
landfill, or put another way, the sludges would not be listed hazardous
waste from the point of generation if they are disposed in a subtitle C
landfill.
As mentioned above, this alternative regulatory approach is based
upon the presumption that disposal of untreated VCM-A sludge in a
subtitle C landfill is protective. However, the Agency also is
concerned that this waste can sometimes fail the TC for mercury (as
discussed earlier, approximately 20 percent of the time based upon EPA
and facility data). The existing treatment standards that otherwise
would apply to this waste if it was characteristically hazardous for
mercury include incineration (i.e., D009 high mercury/organic
subcategory requires either incineration or mercury recovery), which
may not be the most environmentally-sound manner in which to treat the
waste prior to disposal. This is discussed in more detail in the LDR
portion of today's rule (Section V). Because of this concern, this
alternative option is structured in a fashion that allows the treatment
standards being proposed today for K175 to apply in lieu of the
existing standards for D009 for those VCM-A wastes that exhibit the
characteristic for mercury.
EPA requests comment on this proposed alternative listing approach.
Also, EPA requests comment on whether it may be more appropriate to
simply list the VCM-A wastewater treatment sludge unless it is sent to
a subtitle C landfill, and propose alternative LDR treatment standards
that would apply to VCM-A wastewater treatment sludges that exhibit the
TC for mercury. We note that the Agency presently is revisiting the
IMERC standard as part of a comprehensive re-evaluation of the LDR
treatment standards for mercury-bearing wastes (see May 28, 1999 ANPRM;
64 FR 28958). To the extent time allows, the Agency will consider
relevant issues raised in the ANPRM in developing this final listing
determination. However, because of the different schedules of these two
actions and the consent decree deadline for finalizing today's proposed
rule, we will not necessarily be able to consider any comments
submitted to the ANPRM in finalizing today's rule.
The Agency's proposed alternative listing description for VCM-A
wastewater treatment sludges that will define this waste as hazardous
only under certain conditions is as follows:
K175 Wastewater treatment sludges from the production of vinyl
chloride monomer using mercuric chloride catalyst in an acetylene-
based process, unless: i) the sludges are disposed in a subtitle C
landfill, and ii) the sludges do not fail the toxicity
characteristic for mercury in 40 CFR 261.24, and iii) the generator
maintains documentation demonstrating that the waste was disposed of
in a subtitle C landfill or consigned to a transporter or disposal
facility that provided a written commitment to dispose of the waste
in a subtitle C landfill. Respondents in any action brought to
enforce the requirements of subtitle C must, upon a showing by the
government that the respondent managed wastewater treatment sludges
from the production of vinyl chloride monomer using mercuric
chloride catalyst in an acetylene-based process, demonstrate that
they meet the terms of the exclusion set forth above. In doing so,
they must provide appropriate documentation (e.g., contracts between
the generator and the landfill owner/operator, invoices documenting
delivery of waste to landfill, analytical results or other
information showing the waste does not fail the toxicity
characteristic for mercury, etc.) that the terms of the exclusion
were met.
The Agency requests comment on this alternative listing approach
for VCM-A sludge. As already mentioned, EPA might choose this
alternative regulatory approach if it decides direct disposal of
untreated VCM-A sludge is protective without further treatment of this
waste, due to the relative insolubility of mercuric sulfide, and the
groundwater protections a lined landfill does provide.
d. What Is the Status of Landfill Leachate From Previously Disposed
Wastes?
Leachate derived from the treatment, storage, or disposal of listed
hazardous wastes is classified as a hazardous waste by virtue of the
``derived-from'' rule in 40 CFR 261.3(c)(2). The Agency has been clear
in the past that hazardous waste listings apply to wastes disposed
[[Page 46515]]
of prior to the effective date of a listing, even if the landfill
ceases disposal of the waste when the waste becomes hazardous. See 53
FR 31147, August 17, 1988. We also have a well-established
interpretation that listings likewise apply to leachate derived from
the disposal of listed hazardous wastes, including leachate derived
from wastes disposed before a listing effective date which meet the
listing description. We are not reopening any of these issues with this
proposed rulemaking.
Of course, as set out in detail in the August 1988 notice, this
does not mean that landfills holding wastes that are listed now as
hazardous become subject to subtitle C regulation. However, previously
disposed wastes now meeting a listing description, including residues
such as leachate that are derived from such wastes, and that are
managed actively do become subject to subtitle C regulation. See 53 FR
31149, August 17, 1988. In many, indeed most circumstances, active
management of leachate would be exempt from subtitle C regulation
because the usual pattern of management is discharge either to POTWs
via the sewer system, where leachate mixes with domestic sewage and is
excluded from RCRA jurisdiction (see RCRA Section 1004(27) and 40 CFR
261.4(a)(1)), or to navigable waters, also excluded from RCRA
jurisdiction (see RCRA Section 1004(27) and 40 CFR 261.4(a)(2)). In
addition, management of leachate in wastewater treatment tanks prior to
discharge under the CWA is exempt from RCRA regulation (40 CFR
264.1(g)(6)).
If actively managed, landfill leachate and gas condensate derived
from the newly-listed VCM-A waste proposed for listing in today's
notice could be classified as K175. In such circumstances, we would be
concerned about the potential disruption in current leachate management
that could occur, and the possibility of redundant regulation.
Recently, this issue was raised to the Agency in the context of the
petroleum refinery waste listings. See 63 FR 42173, August 6, 1998. A
commenter expressed concern that, because some of the commenter's non-
hazardous waste landfills received newly-listing petroleum wastes prior
to the effective date of the listing decision, the leachate that is
collected and managed from these landfills would be classified as
hazardous. The commenter argued that this could lead to vastly
increased treatment and disposal costs without necessarily any
environmental benefit. After examining and seeking comment on this
issue, we published a final rule that temporarily defers regulation of
landfill leachate and gas condensate derived from certain listed
petroleum refining wastes (K169-K172) that were disposed before, but
not after, the new listings became effective, provided certain
conditions are met. See 64 FR 6806, February 11, 1999.
At the time this issue was brought to the Agency's attention in the
context of the petroleum refinery waste listings, EPA's Office of Water
had recently proposed national effluent limitations guidelines and
pretreatment standards for wastewater discharges--most notably,
leachate--from certain types of landfills. See 63 FR 6426, February 6,
1998. In support of this proposal, EPA conducted a study of the volume
and chemical composition of wastewaters generated by both subtitle C
(hazardous waste) and subtitle D (non-hazardous waste) landfills,
including treatment technologies and management practices currently in
use. EPA proposed effluent limitations (for nine pollutants in the Non-
Hazardous Subcategory) for direct dischargers. See 63 FR 6463. Most
pertinent to finalizing the temporary deferral for the petroleum
refining wastes, EPA did not propose pretreatment standards for
subtitle D landfill wastewaters sent to POTWs because the Agency's
information indicated that such standards were not required.
The conditions included in the temporary deferral published on
February 11, 1999 are that the leachate is subject to regulation under
the Clean Water Act, and the leachate cannot be stored in surface
impoundments after February 13, 2001. See 40 CFR 261.4(b)(15). We
believed that it was appropriate to temporarily defer the application
of the new waste codes to such leachate in order to avoid disruption of
ongoing leachate management activities while the Agency decides how to
integrate the RCRA and CWA regulations consistent with RCRA Section
1006(b)(1). We believe that the same fact pattern fully discussed in
the February 11, 1999 rulemaking applies in this situation as well. As
such, we would be concerned about forcing pretreatment of leachate even
though pretreatment is neither required by the CWA, nor needed.
Therefore, we are proposing to temporarily defer the regulation of
landfill leachate and gas condensate derived from the VCM-A wastes,
with the same conditions as described in 40 CFR 261.4(b)(15) for
petroleum wastes. We believe the issue of whether disruptions can be
minimized through integration of CWA and RCRA rules will be more
amenable to resolution once the CWA rulemaking is completed.
e. What Specific Comments Is EPA Requesting on the Agency's Proposed
Listing of VCM-A Wastewater Treatment Sludges?
The Agency requests comments on the proposed listing of all VCM-A
wastewater treatment sludges as well as the proposed conditional
listing for this waste. In addition, the Agency requests comment on
alternative management practices that may either be in use or may be
appropriate for this wastestream, other than the disposal of these
sludges in subtitle C landfills.
We also request any available information on whether or not the
VCM-A wastes were previously disposed in non-hazardous landfills. Even
if we do not receive any information that previously disposed VCM-A
wastes will result in generation of hazardous landfill leachate and gas
condensate, we may still choose to promulgate the temporary deferral
for landfill leachate and gas condensate from this waste. This is
because someone may discover this problem later (after the effective
date of the listing), so, by having a temporary deferral in place, it
would be possible to avoid disruption of ongoing leachate management
activities while we further examine this issue and await the CWA final
rule.
4. Methyl Chloride Wastewater Treatment Sludges
a. How Is EPA Proposing To Regulate Methyl Chloride Wastewater
Treatment Sludges?
EPA is proposing not to list as hazardous sludges from the
treatment of wastewaters generated from methyl chloride production
processes. This wastestream does not meet the criteria set out at 40
CFR 261.11(a)(3) for listing a waste as hazardous. It does not pose a
substantial present or potential hazard to human health or the
environment. The Agency identified limited risks to consumers of
groundwater.
b. What Information Led EPA To Propose Not To List as Hazardous Methyl
Chloride Wastewater Treatment Sludges?
EPA identified only one facility that generates sludges from the
treatment of wastewaters generated from the production of methyl
chloride and does not currently manage the waste as hazardous. The
results of the RCRA Section 3007 survey for the chlorinated aliphatics
industry show that this facility generates less than 800 metric tons of
this sludge each year and disposes of the sludge in an on-site landfill
along with other wastes from
[[Page 46516]]
the facility. The landfill is lined and has a leachate collection
system.
In conducting the risk assessment for this sludge, EPA considered
one management scenario, disposal in an on-site landfill. The Agency
analyzed potential risks from methyl chloride wastewater treatment
sludge by modeling a non-groundwater pathway. The Agency's analysis of
potential risks due to volatile emissions from the landfill resulted in
negligible risks to individuals in the surrounding area. The Agency
also conducted a bounding (i.e., worst case) risk analysis to estimate
potential risks to groundwater consumers. This analysis used the
leachate concentration measured from a sample of the facility's methyl
chloride wastewater treatment sludge, and assumed the direct ingestion
of this leachate by an adult for a period of 58 years. This bounding
analysis resulted in a risk of 5E-5 for one constituent, arsenic.
The Agency views the arsenic risk results from the bounding
analysis as marginal. Assuming a landfill DAF of only 5 (a reasonable
assumption for an unlined landfill), the predicted risk becomes 1E-5,
which is the typical level identified by EPA as posing sufficient risk
to require the waste to be listed as hazardous(see 59 FR 66072, 66077).
However, for this particular facility, EPA believes that the actual
risk from this waste will be much lower than the risk level predicted
by the bounding analysis given that the landfill currently used by the
single facility generating this waste is lined with a 24-inch clay
liner and has a leachate collection system.
The Agency believes that the management practice of most concern
(on-site landfill) was assessed, given that it is the only management
practice used by the single facility generating the waste. Given that
the landfill is located on site and has significant remaining capacity,
the Agency sees no reason to assume that the facility will not continue
to manage its wastewater treatment sludges from the production of
methyl chloride in this manner.
Based on an analysis of potential risks associated with current
management practices, EPA is proposing not to list as hazardous
wastewater treatment sludges from the production of methyl chloride.
The Agency found no significant risks arising from the on-site landfill
management scenario. The only possible concern arises from the marginal
risk associated with arsenic, which falls at the risk level generally
identified by EPA for listing a waste as hazardous, when assuming a DAF
of 5. The Agency believes this assumption is reasonable for an unlined
landfill, and likely results in an overestimate of risk for the
management practice identified by EPA (i.e., an on-site landfill that
operates with a clay liner and leachate collection at a single
facility).
The Agency requests comments on the approach taken to determine a
no-list proposal for hazardous wastewater treatment sludges from methyl
chloride manufacturing.
5. Allyl Chloride Wastewater Treatment Sludges
a. How Is EPA Proposing To Regulate Allyl Chloride Wastewater Treatment
Sludges?
EPA is proposing not to list as hazardous sludges generated from
treating wastewaters associated with the manufacture of allyl chloride.
This wastestream does not meet the criteria set out at 40 CFR
261.11(a)(3) for listing a waste as hazardous. It does not pose a
substantial present or potential threat to human health or the
environment. The Agency has identified no risks of concern associated
with the current management of the waste.
b. What Information Led EPA To Propose To Not List as Hazardous Allyl
Chloride Wastewater Treatment Sludges?
Wastewater treatment sludges from allyl chloride production are
generated at a single facility. The sludges are generated from the
facility's centralized wastewater treatment system. This wastewater
treatment system is a non-dedicated system in that wastewaters from the
facility's multiple production processes are discharged to the single
system for combined treatment. Wastewaters from the production of allyl
chloride contribute less than two percent to the system's total sludge
loading. According to the RCRA Section 3007 survey response, the sludge
generated from the facility's wastewater treatment system is
incinerated on site in a non-hazardous waste incinerator.
During the investigations undertaken in support of the listing
determinations, EPA collected one sample of this sludge. Two duplicate
TCLP analyses were performed using the sample collected. The sample
also was analyzed for total concentrations of dioxins and furans. The
TCLP analyses indicated the presence of no TCLP constituents above
regulatory levels. The total arsenic concentration in the waste was
11.7 mg/kg, while the total dioxin (TEQ/TCDD) concentration was 11.79
ng/kg.
The Agency does not anticipate any significant risk from the
incineration of allyl chloride wastewater treatment sludge in a non-
hazardous waste incinerator, since both the total arsenic level
47 and the total dioxin level 48 detected in the
sludge are well within the range of background levels of those
constituents in soils.
---------------------------------------------------------------------------
\47\ Alkhatib, Eid, and O'Connor, Timothy, ``Background Levels
of Priority Pollutant Metals in Soil, American Environmental
Laboratory, Vol. 10, No. 3, April, 1998.
Hunter, Philip M., ``Air-Force Wide Background Concentrations of
Inorganics Occurring in Ground Water and Soil,'' Proceedings from
the Fourteenth Annual Waste Testing and Quality Assurance Symposium,
Pp. 73-77, 1998.
Welch, Alan H., Lico, Michael S., and Hughes, Jennifer L.,
``Arsenic in Ground Water of the Western United States,'' Ground
Water, Vol. 26, No. 3, May/June, 1988.
\48\ See Table 4-4 of ``Risk Assessment Technical Background
Document for the Chlorinated Aliphatics Listing Determination,''
EPA, June 25, 1999.
---------------------------------------------------------------------------
The Agency did not conduct an analysis of risk associated with
other management practices, based upon the fact the waste is generated
by a single facility and currently is not managed in a manner other
than non-hazardous waste incineration.
Given that wastewater treatment sludges from allyl chloride
production are generated by a single facility, that the sludge
generated is the product of a facility-wide non-dedicated (i.e., not
process-specific) wastewater treatment system, and that no significant
risks are posed by the waste attributable to the allyl chloride
production process, the Agency is proposing not to list this waste as
hazardous.
The Agency requests comments on the approach taken to determine to
propose not to list as hazardous wastewater treatment sludges from
allyl chloride manufacturing.
F. Constituents Proposed for Addition to Appendix VIII to 40 CFR Part
261
Two of the constituents of concern that are present in the
chlorinated aliphatic wastewaters (K173) and the EDC/VCM wastewater
treatment sludges (K174) proposed to be listed as hazardous waste do
not currently appear on the list of hazardous constituents at 40 CFR
part 261, appendix VIII. Therefore, EPA is proposing to add these two
constituents, octachlorodibenzo-p-dioxin (OCDD) and
octachlorodibenzofuran (OCDF), to appendix VIII. OCDD and OCDF are
members of the large family of polychlorinated dioxins and furans.
Certain of these compounds, most notably, 2,3,7,8 TCDD, have been shown
to be extremely toxic.
As discussed in section III.D of today's proposed rule, the
Agency's risk assessment found significant risks associated with the
presence of dioxins
[[Page 46517]]
in both chlorinated aliphatic wastewaters and EDC/VCM wastewater
treatment sludges. In the case of our analysis of risk for both
categories of waste, the dioxin/furan concentrations were measured on a
TCDD TEQ basis. As previously discussed in today's proposed rule, TCDD
TEQ concentrations are calculated by multiplying each 2,3,7,8 congener
by the appropriate TEF, and then summing the resultant concentrations
to come up with a TCDD TEQ value. OCDD and OCDF are part of this
calculation.
Available data indicate that 2,3,7,8-substituted congeners of
chlorinated dibenzo-p-dioxin and dibenzofurans have toxic effects
similar to 2,3,7,8,-TCDD. Data available from in vivo and in vitro
studies reveal a strong structure-activity relationship, in which the
2,3,7,8-substituted congeners are much more biologically active than
other congeners. Both OCDD and OCDF are 2,3,7,8-substituted congeners.
Available data also show that the relative responses of different PCDDs
and PCDFs are generally consistent across a variety of toxicity end
points. 49 In regard to OCDD specifically, test animals
exhibited initial signs of ``dioxin toxicity'' in a subchronic study of
mice exposed to OCDD at low levels.50
---------------------------------------------------------------------------
\49\ U.S. Environmental Protection Agency. 1989 Update to the
Interim Procedures for Estimating Risks Associated with Exposures to
Mixtures of Chlorinated Dibenzo-p-Dioxins and -Dibenzofurans (CDDs
and CDFs). Washington, D.C.: Risk Assessment Forum, March, 1989.
EPA/625/3-89/016.
\50\ Couture, L.A., M.R. Elwell, and L.S. Birnbaum. ``Dioxin-
like Effects Observed in Male Rats Following Exposure to
Octachlorodibenzo-p-dioxin (OCDD) during a 13-week Study.''
Toxicology and Applied Pharmacology, Vol. 93, Pp 31-46, 1988.
---------------------------------------------------------------------------
EPA also points out that the oral slope factors for OCDD and OCDF
(calculated by multiplying the cancer slope factor for 2,3,7,8 TCDD by
the TEFs for OCDD and OCDF, which are both 0.0001 51) are
relatively high (15/(mg/kg)/day) compared to the oral slope factor of
other hazardous constituents currently listed in appendix VIII to 40
CFR 261 (e.g., arsenic has an oral slope factor of 1.5/(mg/kg)/day).
---------------------------------------------------------------------------
\51\ Using the toxicity equivalency factor (TEF) developed by
the World Health Organization, see section III.D.1.g.ii of today's
proposed rule for discussion of TEFs.
---------------------------------------------------------------------------
Therefore, we have concluded that, based upon sufficient evidence
to show that OCDD and OCDF are hazardous constituents and based upon
the fact that OCDD and OCDF are the only congeners that make up TCDD
TEQ that are not currently listed in appendix VIII, OCDD and OCDF
should be added to appendix VIII of 40 CFR part 261. The Agency
requests comment on its proposal to add OCDD and OCDF to the list of
hazardous constituents in appendix VIII to 40 CFR 261.
IV. Economic Analysis
A. What Is the Purpose of the Economic Analysis?
The primary purpose of the economic analysis presented in the
``Economic Background Document,'' is to estimate potential industry
compliance costs associated with this listing proposal. Secondary
purposes are to provide descriptive information about the economic
(industry) sectors affected, and about the economic activities
involving chlorinated aliphatic hydrocarbon chemicals (CAHCs). The
Economics, Methods, and Risk Assessment Division (EMRAD) of EPA's
Office of Solid Waste (OSW) conducted the economic analysis. The
``Economic Background Document'' is available to the public from the
RCRA docket (refer to the introduction to this preamble for
instructions on how to obtain a copy). The findings of the economic
study are summarized in this section of the preamble. References to
statements below pertaining to facts, data, assumptions and other types
of information, are identified in the document.
B. How May the Public Participate in the Economic Analysis?
The USEPA encourages the public to provide comments and suggestions
about the design, accuracy, representativeness and completeness of the
``Economic Background Document.''
In preparing the Economic Background Document, the EPA preferred to
the maximum extent possible, to use publicly-available rather than
confidential business information (CBI) as information and data
sources, to facilitate transparency for public review and comment.
However, some information was designated by survey companies as CBI
when collected in the 1992 and 1997 Section 3007 surveys administered
by EPA (described elsewhere in this preamble). Consequently, the
background data and information available to the EPA during development
of this listing proposal also consisted of CBI information. In order to
minimize reliance on CBI data, and to exhaust available public
information sources, EPA consulted many other databases as supplements
and substitutes to the RCRA Section 3007 survey, in conducting the
economic study.
EPA particularly requests written comments from the public on the
information elements listed below pertaining to the economic analysis
presented in the ``Economic Background Document:''
1. Study Design: Suggestions for modifications and improvements
to the scope, methodology, and organization of the Economic
Background Document (e.g., 30-year cost annualization ``period-of-
analysis'' applied).
2. Facility Universe: Correct number and locations of CAHC
manufacturing and any other types of facilities and entities
potentially affected by the RCRA listing proposal.
3. Affected Wastes: Correct average annual quantities, types and
industrial source (origin) of potentially affected CAHC
manufacturing wastes.
4. Industry Profile: Characterization of the role, functions and
industrial organization associated with the production and use of
CAHCs in the US economy.
5. Baseline Waste Management: Characterization of baseline
(current) waste management practices associated with CAHC
manufacturing wastes (both onsite and offsite management practices),
including the types and relative waste quantities managed, types of
waste management units, costs of waste management ($/ton basis),
waste commingling and segregation, etc. In particular, there is
uncertainty in the Section 3007 survey data, about the exact number
and sizes of wastewater management tanks used by CAHC manufacturing
facilities.
6. Compliance Waste Management: Adaptation of CAHC manufacturing
facilities to the RCRA listing proposal if finalized, such as
changes in CAHC manufacturing plant & equipment, facility layout,
production processes and methods, business arrangements, CAHC
product mixes, etc. What are possible operating consequences to
waste management facilities for meeting K175 waste pH and sulfide
landfill restrictions?
7. Facility Process Modifications: Identification and dollar
value of lump-sum capital investment costs required (per industrial
operating unit or facility).
8. Unit Costs: Overall representativeness of unit costs applied
to the universe of CAHC manufacturing facilities for industrial
waste management, involving both non-hazardous and hazardous waste
handling.
9. Impact Benchmarks: The appropriateness of the alternative
company financial benchmarks (e.g., annual sales revenues, annual
profits, capital expenditures, short-term credit) presented in this
study, and of other benchmarks not presented, for purpose of
providing measurement references relative to assessing the dollar
magnitude of the estimated industry compliance costs.
10. Supporting Data: The data applied in the economic study are
from sources published over a number of years, and for some key data
elements, are more than five years old (e.g., during preparation of
this study, the US Bureau of Census' 1997 Survey of Manufacturers
data reports were not yet available).
11. Other Considerations: Any other comments pertaining to other
aspects of the economic study, or to topics which have been omitted
or are outside the scope of the
[[Page 46518]]
study, if relevant to assessing the economic impact of the listing
proposal.
C. How Are Chlorinated Aliphatic Chemicals Used in the Economy?
Chlorinated aliphatic hydrocarbon chemicals (CAHCs) entered into
commerce in the US in the early 1920s, and as of 1994, approximately 38
billion pounds of 50 different commercially significant CAHCs were
manufactured by 23 chemical plants (facilities) in the United States.
The US production of CAHCs has grown an average annual rate of 4.4
percent over the last 30 years.
CAHCs are a group of organic chemicals--most of which are colorless
liquids at room temperature--primarily used as intermediate feedstocks
for the production of polyvinyl chloride (PVC) plastics; CAHCs are also
used directly in liquid form as various types of solvents, as
intermediates for the production of other types of chemicals, and in
assorted other commercial use categories. As of 1996, three CAHCs--
ethylene dichloride, vinyl chloride, methyl chloride--were on the list
of top-50 chemicals produced in the United States.
D. Where Are CAHCs Manufactured in the United States?
In conjunction with contacts of industry representatives, EPA
identified an initial subset of industrial facilities relevant to the
scope of the listing proposal, according to both the (a) types of
chemical products manufactured, as well as the (b) types of industrial
wastestreams generated from the chemical manufacturing processes. EPA
identified a total of 28 facilities in the 1992 Section 3007 industry
survey, and a total of 26 facilities in the 1997 follow-up survey, as a
result of two facility closures in the interim period. Three of the 26
facilities were discovered to be either ``de minimus'' producers of
CAHCs, or double-counted in the survey, which resulted in a final
subset of 23 relevant CAHC manufacturing facilities.
The relevant subset of 23 CAHC manufacturing facilities surveyed in
USEPA-OSW's 1997 survey are located in eight states (Kansas, Kentucky,
Louisiana, Maryland, Michigan, New York, Tennessee, and Texas), and
employ an average of over 700 employees per facility. Total employment
for all 23 facilities is about 19,000 employees, and the total
employment associated with the 16 parent companies which own these 23
facilities is much larger, estimated at 526,700 employees.
E. Have CAHCs Been Produced Historically in Other Locations in the
United States?
In addition to current databases, there are assorted documents
which contain historical information about the CAHC production industry
in the United States. Historically, CAHCs have been manufactured and/or
used as feedstocks and intermediates in chemical production plants in
at least 15 states in the US. The historical data on the number and
location of CAHC production facilities serves to illustrate the dynamic
business activity in this industry sector. As late as 1975, CAHCs were
produced in the US by 32 companies in 58 plant locations.
F. What Are the Estimated Potential Industry Costs of This Listing?
There are two associated categories of potential compliance costs
for CAHC manufacturers under this listing proposal: (a) process
wastewater listing costs, and (b) wastewater treatment sludge listing
costs. These costs are incremental to current waste management costs in
this industry, in the sense that all CAHC manufacturing facilities are
currently regulated under RCRA (i.e., as chlorinated aliphatic
manufacturers via the existing RCRA F025 and F026 wastecodes, among
others), and some facilities currently manage most or all of their CAHC
manufacturing wastes as hazardous. Consequently, this listing proposal
will not have a full incremental impact on these facilities, and the
marginal impact on their existing operations in relation to current
RCRA compliance and hazardous waste handling practices may be less than
it otherwise would be if these companies and facilities did not have
experience with baseline RCRA waste management practices.
As summarized in Table IV-1 below, EPA estimates the total industry
compliance cost--excluding paperwork burden as separately estimated in
the Information Collection Request--associated with the two wastestream
components of the listing proposal (i.e., sludges and wastewaters), at
$2.355 million in average annual cost, for annual waste management in
conformance with the terms of the listing proposal. This total cost
consists of an estimated $1.320 million in initial capital expenditures
(30-year annualized equivalent of $0.046 million), and an estimated
$2.309 million in recurring annual costs.
Table IV-1.--Summary of Estimated Industry Compliance Costs for the RCRA
Listing Proposal; Wastewater Treatment Sludges and Wastewaters. Average
Annual Equivalent Total Industry Cost
------------------------------------------------------------------------
Type of CAHC facility
potentially affected by Initial Recurring
Item the proposed RCRA listing capital costs annual O&M
options ($ lump-sum) costs ($/year)
------------------------------------------------------------------------
A. SLUDGE LISTING ESTIMATED
COSTS:
A1 Non-landfilled EDC/VCM $0 $1,333,000
sludge.
A2 VCM-A process w/mercury 0 209,000
catalyst.
-----------------------------------------------------------
Subtotal sludge costs. 0 1,542,000
B. WASTEWATER LISTING
ESTIMATED COSTS:
B1 Tank fixed roof + valve. 1,084,600 81,600
B2 Tank roof vent + carbon 150,900 591,200
control.
B3 Tank ``Subpart CC'' 0 23,700
ancillary costs*.
B4 Initial waste testing 84,500 0
for dioxins.
B5 Annual waste retesting 0 70,400
for dioxins.
-----------------------------------------------------------
Subtotal wastewater 1,320,000 766,900
costs.
-------------------------------
C. SLUDGE + WASTEWATER COSTS 1,320,000 2,309,000
(column totals).
===============================
[[Page 46519]]
Total annualized .............. 2,355,000
equivalent cost.
------------------------------------------------------------------------
V. Proposed Treatment Standards Under RCRA's Land Disposal
Restrictions
A. What Are EPA's Land Disposal Restrictions (LDRs)?
The RCRA statute requires EPA to establish treatment standards for
all wastes destined for the land disposal. These are the so called
``land disposal restrictions'' or LDRs. For any hazardous waste
identified or listed after November 8, 1984, EPA must promulgate these
LDR treatment standards within six months of the date of identification
or final listing (RCRA Section 3004(g)(4), 42 U.S.C. 6924(g)(4)). RCRA
also requires EPA to set as these treatment standards ``* * * levels or
methods of treatment, if any, which substantially diminish the toxicity
of the waste or substantially reduce the likelihood of migration of
hazardous constituents from the waste so that short-term and long-term
threats to human health and the environment are minimized.'' (RCRA
Section 3004(m)(1), 42 U.S.C. 6924(m)(1)).
Wastes that meet treatment standards established by EPA may be land
disposed. Wastes that do not meet these standards are prohibited from
land disposal (except in so-called no-migration units). Each waste
proposed for listing as hazardous in this rule will be subject to all
the land disposal restrictions on the same day their respective listing
becomes effective.
B. How Does EPA Develop LDR Treatment Standards?
To establish LDR treatment standards, EPA first identifies the best
demonstrated available technology (BDAT) for the hazardous constituents
present in the hazardous waste, and then determines what constituent
concentrations can be achieved by the technology or technologies
identified as BDAT.
EPA typically has established treatment standards based on
performance data from the treatment of the waste at issue, if such data
are available, and also from the treatment of wastes with similar
chemical and physical characteristics or similar concentrations of
hazardous constituents. Treatment standards typically cover both
wastewater and nonwastewater waste forms on a constituent-specific
basis. The constituents selected for regulation under the LDR program
are not necessarily limited to those present in a proposed listing, but
also may include those constituents or parameters that will ensure that
treatment technologies are operated properly. For listed waste EPA
identifies these as ``regulated constituents'' and they appear
individually in the Table at 40 CFR 268.40, along with their respective
treatment standards.
EPA may develop and promulgate either technology-specific treatment
standards or numerical treatment standards. Should EPA elect to use
technology-specific standards, all wastes that meet the listing
designations would have to be treated by the technology or technologies
specified before disposal. These technologies are also identified in
the Table at Sec. 268.40 and are further described in Sec. 268.42.
Should EPA elect to use numerical treatment standards, the Agency
allows the use of any technology (other than impermissible dilution) to
comply with the treatment standards.
After developing the LDR treatment standards, we must also
determine if significant treatment capacity is available to treat the
expected volumes of wastes. If so, the LDR treatment standards become
effective essentially at the same time a listing does. If not, EPA may
grant up to a two-year national capacity variance (NCV) during which
time the LDR treatment standards are not effective.
For a more detailed overview of the Agency's approach for
developing treatment standards for hazardous wastes, see the final rule
on solvents and dioxins (51 FR 40572, November 7, 1986) and section
III.A.1 of the preamble to the final rule that set land disposal
restrictions for the ``Third Third'' wastes (55 FR 22535, June 1,
1990). EPA also has explained its BDAT procedures in ``Best
Demonstrated Available Technology (BDAT) Background Document for
Quality Assurance/Quality Control Procedures and Methodology (EPA/OSW,
October 23, 1991)'' . This document is available in the docket
supporting this rulemaking.
C. What Kind of Treatment Standards Are Proposed?
EPA has gathered data on waste characteristics and current
management practices for wastes proposed in this action as part of the
administrative record for this rule, and has evaluated these data to
develop specific treatment standards. An examination of the
constituents that are the basis of the proposed listings shows that the
Agency has previously developed numerical treatment standards for most
of the constituents of concern. After reviewing the available
characterization data and the available information on waste management
practices for these wastes proposed for listing, EPA has determined
that it is technically feasible and justified to apply existing
universal treatment standards (UTS) to the regulated hazardous
constituents of concern in the wastes proposed to be listed as K173 and
K174. For K175, EPA is proposing a metals recovery requirement as the
treatment standard, namely roasting and retorting. Although the mercury
in K175 would be recovered, other treatment residuals will exist. For
these residuals, we are proposing that existing UTS will be applicable.
Available information also shows that these wastes and the
treatment residuals can be managed in existing treatment and
reclamation units that routinely manage similar or as-difficult-to-
treat hazardous wastes that currently are prohibited from land
disposal. The BDAT background document provides further information on
EPA's rationale for applying UTS to these wastes and the treatment
standard of metals recovery to K175. Also see LDR Phase II final rule,
59 FR 47982, September 19, 1994, for a further discussion of UTS.
For proposed K173 and K174, EPA is proposing to regulate specific
constituents from each of these hazardous wastes. A list of the
proposed regulated hazardous constituents and
[[Page 46520]]
the proposed treatment limits can be found in the following preamble
section and in the proposed regulatory Table 268.40--Treatment
Standards for Hazardous Wastes. If EPA makes a final decision to list
the identified wastes, these constituents and standards would apply.
EPA has provided in the BDAT background document a review of
thermal and nonthermal technologies that can be used to meet the
proposed numerical concentration limits for proposed K173 and K174,
assuming the design and operation of these technologies are optimized.
Since EPA is proposing numerical concentration limits, the use of other
technologies capable of achieving the proposed treatment standards is
allowed, except for those treatment or reclamation practices
constituting land disposal or impermissible dilution (see 40 CFR
268.3). As noted above, EPA is proposing a specified technology-
specific treatment standard for K175. K175 waste would therefore have
to be treated by the required technology and the residues thereof or
subsequent residues would have to meet numerical UTS concentration
limits. 52
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\52\ There are two exceptions. Where the treatment technology is
not appropriate to the waste, regulations provide a petition process
whereby the generator or treatment facility may petition the
Administrator for a variance. See 40 CFR 268.44. In addition,
persons can petition the Administrator for an alternate treatment
method by showing that the alternate method can achieve a measure of
performance equivalent to the method specified by rule.
---------------------------------------------------------------------------
D. Other LDR-Related Provisions
We propose that the provisions in 40 CFR 268.45 would also be
applicable for the treatment and disposal of hazardous debris
contaminated with proposed K173, K174, and K175. Hazardous debris
treated in accordance with the provisions of 40 CFR 268.45 may be
allowed for land disposal in a hazardous waste disposal facility. As a
result, debris contaminated with proposed K173, K174, and K175 would be
required to be treated prior to land disposal, using specific
technologies from one or more of the following families of debris
treatment technologies: extraction, destruction, or immobilization.
Residuals generated from the treatment of debris contaminated with
proposed K173, K174, or K175 will have to meet the applicable UTS
limits proposed today. See 57 FR 37277, August 18, 1992, for additional
information on the applicability, scope, and content of the hazardous
debris provisions.
We note that, when the listings proposed today become final, the
alternative soil treatment standards in 40 CFR 268.49 would be
available for any soils contaminated with the newly listed wastes.
Soils that must meet LDRs before land disposal may be treated to the
levels in the alternative soil treatment standards as long as the soils
will not be used in a manner constituting disposal. Even though EPA is
proposing a method of treatment for K175, the waste contains an
analyzable hazardous constituent. Consequently, the alternative
treatment standards may apply and specify that the analyzable
constituent must be at specified levels for soil contaminated with the
waste to be disposed. See 268.49(c)(3)(B), promulgated at 63 FR 28751.
Such soils can only be land disposed (here, recycled by being placed on
the land) if they first meet UTS. See 63 FR 28609-28610 (May 26, 1988).
A facility is not required to use these alternative soil treatment
standards and may elect to comply with the traditional LDR treatment
standards for process waste. The choice of whether to do so potentially
impacts how many constituents must meet LDR treatment standards. If a
site chooses to meet the alternative soil treatment standards and their
soils are contaminated with a listed waste, then they are required to
treat both the regulated hazardous constituents specified in 268.40 and
also any underlying hazardous constituents. Potential underlying
hazardous constituents are listed in the UTS Table at 268.48. However,
if the traditional treatment standards are applied to a soil
contaminated with a listed waste, then only the regulated constituents
specified in 268.40 must meet the treatment standards. For further
discussion of the alternative soil treatment standards, please refer to
the final Phase IV LDR rule (63 FR 28556, 28609, May 26, 1998) and the
subsequent clarification notice (64 FR 25410-25411, May 11, 1999).
Lastly, because land disposal also includes placement in injection
wells (40 CFR 268.2(c)) application of the land disposal restrictions
to proposed K173, K174, and K175 requires the modification of injection
well requirements found in 40 CFR 148. We propose that K167 and K168 be
prohibited from underground injection. See 40 CFR 148. Therefore,
wastes proposed to be listed as K173, K174, and K175 may not be
underground injected unless they have been treated in compliance with
the LDR treatment standards or a no migration petition for these wastes
has been approved.
E. What Standards Is EPA Proposing for K173?
EPA is proposing to apply existing Universal Treatment Standards to
proposed K173 wastes. We have examined the constituents that comprise
the basis of the proposed listing and identified the presence of those
other constituents near on in excess of current numerical universal
treatment standards. Wastes that exceed these levels require treatment
of the constituents to diminish the toxicity of the waste and to reduce
the likelihood of migration of the hazardous constituents. Based on
this examination, we propose treatment standards for bis(2-
chloroethyl)ether, chloroform, pentachlorophenol, phenol, 2,4,6-
trichlorophenol, chromium(total), and nickel in addition to
tetrachlorodibenzodioxins, pentachlorodibenzodioxins,
hexachlorodibenzodioxins, heptachlorodibenzodioxins,
tetrachlorodibenzofurans, pentachlorodibenzofurans,
hexachlorodibenzofurans, heptachlorodibenzofurans, OCDD, and OCDF in
proposed K173.
Existing LDR standards for the wastes that contain chlorinated
dibenzo-para-dioxins and dibenzofurans are expressed in terms of all
tetrachlorodibenzo-p-dioxins, pentachlorodibenzo-p-dioxins,
hexachlorodibenzo-p-dioxins, tetrachlorodibenzofurans,
pentadibenzofurans, hexachlorodibenzofurans, OCDD, and OCDF. Today's
notice proposes treatment standards for five additional dioxin/furan
congeners, namely 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin,
1,2,3,4,6,7,8-heptachlorodibenzofuran, 1,2,3,5,7,8,9-
heptachlorodibenzofuran, OCDD, and OCDF. We are doing so because these
constituents are present at concentrations that present significant
risks should proposed hazardous waste K173 be mismanaged.
For proposed K173 nonwastewaters, we propose that the LDRs for the
three new congeners (1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin,
1,2,3,4,6,7,8-heptachlorodibenzofuran, 1,2,3,5,7,8,9-
heptachlorodibenzofuran, OCDD, and OCDF) be set at the quantitation
limits of method 8280A. These quantitation limits are achievable
routinely, and being 3 to 4 times the detection limit of residues from
combustion, they are a reasonable approximation of 2.8 times the method
detection limit normally used to develop treatment standards from
detection limit data to account for
[[Page 46521]]
potential treatment variability. 53 Since method 8280A was
first developed, the more sensitive high-resolution mass spectrometry
method 8290 has been developed. Method 8290 may achieve detection
limits orders of magnitude more sensitive than Method 8280A. However,
we lack actual treatment performance data for these wastes using method
8290. Further, because of the trace levels of dioxins/furans that
method 8290 is capable of detecting, we can not presume that combustion
would achieve the much lower non-detectable levels of method 8290.
Therefore, we are proposing to base treatment standards for the five
congeners cited above on the more widely available method 8280A. We
specifically invite data to be submitted on the levels that can be
achieved using method 8290.
---------------------------------------------------------------------------
\53\ See Best Demonstrated Available Technology (BDAT)
Background Document for Quality Assurance/Quality Control Procedures
and Methodology, EPA, October 23,1991.
---------------------------------------------------------------------------
From past trial burns, we have confidence that incineration has
been fully demonstrated for treating dioxin-containing wastes. As
explained in 1989 solvents and dioxin rule, Method 8280A failed to
detect chlorinated dibenzo-p-dioxins and dibenzofurans in residues from
trial burns. This has led the Agency to conclude that the residual
levels of chlorinated dibenzo-p-dioxins and dibenzofurans that remain
after treatment would be well below the levels proposed. See 51 FR
1734, January 14, 1986. Therefore, for the three new congeners, we are
proposing standards based on these data showing that high temperature
thermal treatment achieved destruction of these constituents to levels
below the stated quantitation limits of method 8280A.
For proposed K173 wastewaters, we propose that the UTS treatment
level of 0.000035 mg/L for pentachlorodibenzofuran be transferred to
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8-
heptachlorodibenzofuran, and 1,2,3,5,7,8,9-heptachlorodibenzofuran.
Pentachlorodibenzofuran is a structural homologue of these constituents
with similar physical properties, which allows us to assume similar
treatment efficiencies. Similarly, we propose that the UTS treatment
level of 0.000063 mg/L for tetrachlorodibenzofuran be transferred to
OCDD and OCDF. For all other dioxin/furan congeners, we propose to
transfer the current, corresponding universal treatment standards.
For the specific numerical standards proposed to be applicable to
proposed K173, see the proposed amendments to 40 CFR 268.40 at the end
of this preamble. We request comment on the proposed treatment
standards for proposed K173.
F. What Standards Is EPA Proposing for K174?
EPA is proposing to apply existing Universal Treatment Standards
(UTS) to these wastes. We have examined the constituents that comprise
the basis of the proposed listing and identified the presence of those
other constituents near on in excess of current numerical universal
treatment standards. Waste that exceed these levels require treatment
of the constituents to diminish the toxicity of the waste and to reduce
the likelihood of migration of the hazardous constituents. Based on
this examination, we propose that wastes proposed to be listed as K174
be treated for arsenic, tetrachlorodibenzo-p-dioxins,
pentachlorodibenzo-p-dioxins, hexachlorodibenzo-p-dioxins,
heptachlorodibenzo-p-dioxins, tetrachlorodibenzofurans,
pentachlorodibenzofurans, hexachlorodibenzofurans,
heptachlorodibenzofurans, OCDD, and OCDF. We are proposing to apply the
new numerical standards for the five new congeners (one
heptachlorodibenzo-p-dioxin, two heptachlorodibenzofurans, OCDD, and
OCDF), discussed in the previous section, to proposed hazardous waste
K174 because these constituents are also present in proposed K174
wastes at significant concentrations that would present risks should
the wastes be mismanaged.
We request comment on the proposed treatment standards for wastes
proposed to be listed as K174.
G. What Standards Is EPA Proposing for K175?
Proposed hazardous waste K175 is generated from the treatment of
catalyst change-out wastewaters from the chlorination of acetylene on a
mercuric chloride catalyst. As with the above wastes, we have examined
the constituents that comprise the basis of the proposed listing and
identified the presence of mercury as the only constituent that would
require treatment to diminish the toxicity of the waste and to reduce
the likelihood of migration. Proposed K175 contains in excess of 260
mg/kg mercury and is greater than one percent in organic constituents.
This type of waste profile is similar to wastes that are currently
deemed to be characteristically hazardous under the D009 waste code.
Therefore, in assessing what type of LDR treatment standards are
warranted for proposed K175, we look first to the D009 treatment
standards.
Current regulations for similar D009 wastes require either
retorting or roasting (RMERC) or incineration in units operated in
accordance with the technical operation requirements of 40 CFR Part
264, Subpart O and Part 265, Subpart O (IMERC ). However, current
regulations do not require combustion units to capture and recover
mercury from the combustion gases produced. If all the mercury
contained in these wastes were combusted without capture and removal,
the result would be over one metric ton per year of mercury emissions.
Under the upcoming revisions to the hazardous waste combustion
regulations, it is not clear that facilities are going to choose to
employ air pollution control devices (capture and removal devices) to
comply with mercury emission limits. They might instead simply choose
to reduce their feed rate, which will not reduce the total amount of
mercury emitted over the long term. Given this uncertainty about future
compliance strategies by the hazardous waste combustion industry, we
are proposing that mercury recovery by retorting or roasting (RMERC) be
the required treatment technology for this waste. RMERC requires
processing in devices subject to mercury emission controls resulting in
mercury capture and removal, and also subject to emission standards
such as the National Emissions Standard for Hazardous Air Pollutants
(NESHAP) for mercury. See 40 CFR 268.42. For residues of the RMERC
process, we propose to adopt the current standard of 0.20 mg/L TCLP
mercury.
The Agency has contacted a treatment vendor of RMERC technology who
indicated that treatment of the subject wastes may be difficult, but is
possible.54 We therefore request treatment performance data
regarding the use of retorting for these waste.
---------------------------------------------------------------------------
\54\ Personal communication with John Boyle, Bethlehem Apparatus
Co., Inc.
---------------------------------------------------------------------------
Absent definitive treatment data, we have considered whether an
alternative treatment standard to retorting might be feasible to
propose for comment. One alternative is to establish a numerical
concentration limit. Under current regulations, mercury wastes that are
stabilized are subject to a standard of 0.025 mg/L TCLP mercury. This
differs from the initial option of retorting in two key respects.
First, use of specific treatment technology would not be required and,
second, the treated waste or waste residuals would be subject to a
numerical standard about one order of
[[Page 46522]]
magnitude more stringent--0.2 mg/L for retorting residuals under the
first option vs. 0.025 mg/L for all treatment residuals under this
second option.
Without the assurance of treatment that a requirement for retorting
would provide, the tighter standard of 0.025 mg/L TCLP is appropriate
to propose as a potential treatment standard. This standard would apply
to all treatment residuals included in the listing description for
proposed hazardous waste K175, regardless of the type of treatment
used. In practice, this standard would involve the immobilization of
the mercury in the waste before land disposal. If regulations were to
be promulgated in this form, the waste could be land disposed if a
standard of 0.025 mg/L TCLP mercury was achieved using any technology
other than impermissible dilution.
Calculated solubilities of mercury sulfide (metacinnabar) as a
function of pH have revealed that above pH 6.0 the presence of sulfide
complexes results in significantly increased solubility.55
Preliminary results from constant pH leaching measurements of the
subject waste, as part of an on-going study, have shown similar
results.56 At pH 6.0 the waste tested leached 0.0058 mg/L.
However, at pH 10, 1.63 mg/L mercury was solubilized. Current landfill
disposal site conditions for this waste are reported to be pH 9.48-
9.57.57 Under these conditions, mercury in the waste would
be expected to be mobilized especially if excess sulfides were present.
Therefore, controlled treatment and disposal conditions are warranted
to avoid mobilization of the mercury in the waste, which could pose a
significant threat to human health and the environment. To insure
operational stability of the treatment process and proper long-term
disposal, EPA proposes two conditions as part of the LDR treatment
standards. First, the waste residue generated, if in mercuric sulfide
form, must itself be pH 6.0 or below. We therefore propose that
mercuric sulfide residues of this waste be treated to attain a pH of
less than or equal to 6.0. Second, if proposed K175 wastes are to be
co-disposed in a landfill with other wastes, co-disposal will be
restricted to wastes with similar pH (i.e., not greater than 6.0). To
comply with these requirements disposal facilities would be required to
certify and maintain operating records available for inspection of
codisposed wastes to demonstrate compliance.
---------------------------------------------------------------------------
\55\ H. Lawrence Clever, Susan A. Johnson, and M. Elizabeth
Derrick, The Solubility of Mercury and Some Sparingly Soluble
Mercury Salts in Water and Aqueous Electrolyte Solutions, J. Phys.
Chem. Ref. Data, Vol. 14, No. 3, 1985, page 652.
\56\ Paul Bishop, Renee A. Rauche, Linda A. Rieser, Markram T.
Suidan, and Jain Zhang; ``Stabilization and Testing of Mercury
Containing Wastes,'' Draft, Department of Civil and Environmental
Engineering, University of Cincinnati, March 31, 1999. Please note
that this is a draft EPA document not yet peer reviewed. Also, data
within the report is still undergoing QA/QC review, and the text,
data, and conclusions in the report may change before the document
is finalized.
\57\ May 14, 1999, landfill parameters, e-mail from Mitch Hahn,
Waste Management.
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Currently, the wastes proposed to be listed as K175 are landfilled
after treatment has converted mercuric chloride in wastewaters to
mercuric sulfide. We believe significant opportunities exist for source
reduction and waste minimization to reduce or eliminate the generation
of this waste. For example, the need to hydroblast spent mercuric
chloride catalyst from reactors could be eliminated by internal
segmentation of the reactor bed that would allow the segments to be
sent intact for mercury recovery. Thus, generation of the waste could
be eliminated or significantly reduced. Beyond modifications to the
physical plant, the treatment of the wash waters could be modified to
incorporate addition of caustic and organic phase separation. This
would result in a mercuric oxide sludge more amenable to recovery by
retorting prior to sulfide treatment of the resulting brine. As a
result of such changes, a smaller volume of mercuric sulfide sludge
with reduced organic content would be generated, as would a larger
volume of a more easily recoverable mercuric oxide sludge.
We request treatment performance data on the treatment standards
proposed and on other alternative treatment technologies that would
meet the statutory criteria for all LDR standards ``minimizing threats
to human health and the environment by reductions in the toxicity or
mobility of the wastes through the treatment process. We also request
comment on the feasibility of source reduction and waste minimization
alternatives described above.
H. What Other Land Disposal Restrictions Aspects Are There to the
Proposal?
EPA is proposing to add the numerical standards derived for the
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8-
heptachlorodibenzofuran, 1,2,3,4,7,8,9-heptachlorodibenzofuran,
1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,6,7,8,9-
octachlorodibenzofuran (OCDF) to the Table of Universal Treatment
Standards (UTS) at 40 CFR 268.48. These constituents have been shown to
represent significant risks to human health or the environment in the
risk assessment accompanying this proposal, and their presence in other
wastes should be mitigated to avoid similar risks. If promulgated, all
characteristic wastes which have these constituents as underlying
hazardous constituents above the UTS thus will require treatment of
those constituents before land disposal.
Furthermore, we are proposing that the constituents 1,2,3,4,6,7,8-
heptachlorodibenzo-p-dioxin; 1,2,3,4,6,7,8-heptachlorodibenzofuran,
1,2,3,4,7,8,9-heptachlorodibenzofuran; OCDD; and OCDF be added to the
list of regulated constituents in hazardous waste F039 multisource
leachate. F039 applies to multiple listed hazardous waste landfill
leachates in leu of the original waste codes, and F039 wastes are
subject to all numerical treatment standards applicable to all listed
wastes. To maintain regulatory consistency with this regulatory
architecture and the implementation benefits of having one waste code
for multisource leachate, the treatment standards for F039 are updated
each time a new LDR standard is developed for listed wastes. As a
result, if today's proposal is ultimately promulgated, all leachate
(liquids that have percolated through land disposed wastes) resulting
from the disposal of more than one restricted hazardous waste will have
to meet UTS for all hazardous constituents above the UTS.
I. Is There Treatment Capacity for the Proposed Wastes?
1. What Is a Capacity Determination?
EPA must determine whether adequate alternative treatment capacity
exists nationally to manage the wastes subject to LDR treatment
standards. RCRA section 3004 (h)(2). Thus, LDRs are effective when the
new listings are effective as well (typically 6 months after the new
listings are published in the Federal Register), unless EPA grants a
national capacity variance from the otherwise-applicable date and
establishes a different date (not to exceed two years beyond the
statutory deadline) based on ``* * * the earliest date on which
adequate alternative treatment, recovery, or disposal capacity which
protects human health and the environment will be available'' (RCRA
section 3004(h)(2), 42 U.S.C. 6924(h)(2)).
Our capacity analysis methodology focuses on the amount of waste
currently disposed on the land, which will require alternative or
additional treatment as a result of the LDRs. The quantity of wastes
that is not disposed
[[Page 46523]]
on the land, such as discharges regulated under NPDES, discharges to a
POTW, or treatment in a RCRA-exempt tank, is not included in the
quantities requiring additional treatment as a result of the LDRs.
Also, land-disposed wastes that do not require alternative or
additional treatment are excluded from the required capacity estimates
(i.e., those that currently are treated to meet the LDR treatment
standards). Land-disposed wastes requiring alternative or additional
treatment or recovery capacity that is available on site or within the
same company also are excluded from the required commercial capacity
estimates. The resulting estimates of required commercial capacity then
are compared to estimates of available commercial capacity. If adequate
commercial capacity exists, the waste is restricted from further land
disposal. If protective alternative capacity does not exist, EPA has
the authority to grant a national capacity variance.
In making the estimates described above, the volume of waste
requiring treatment depends on the current waste management practices
employed by the waste generators before this proposed regulation is
promulgated and becomes effective. Data on waste management practices
for these wastes were collected during the development of this proposed
rule. However, we realize that as the regulatory process proceeds,
generators of these wastes may decide to minimize or recycle their
wastes or otherwise alter their management practices. Thus, we will
monitor changes and update data on current management practices as
these changes will affect the volume of wastes ultimately requiring
commercial treatment or recovery capacity.
The commercial hazardous waste treatment industry can change
rapidly. For example, national commercial treatment capacity changes as
new facilities come on line or old facilities go off line, and as new
units and new technologies are added at existing facilities. The
available capacity at commercial facilities also changes as facilities
change their commercial status (e.g., changing from a fully commercial
to a limited commercial or ``captive''--company owned--facility). Thus,
EPA also continues to update and monitor changes in available
commercial treatment capacity.
We request data on the annual generation volumes and
characteristics of wastes affected by this proposed rule, including
proposed hazardous wastes K173, K174, and K175 in wastewater and
nonwastewater forms, soil or debris contaminated with these wastes,
residuals generated from the treatment or recycling of these wastes,
and the current and planned management practices for the wastes, waste
mixtures, and treatment residuals.
We also request data on the current treatment or recovery capacity
capable of treating these wastes, facility and unit permit status
related to treatment of the proposed wastes and any plans that
facilities may have to expand or reduce existing capacity, or construct
new capacity. Of particular interest to us are waste characteristics,
such as pH, total organic carbon content, constituent concentrations,
and physical forms that may limit the availability of certain treatment
technologies. Also of interest are any analytical difficulties
associated with identifying and monitoring the regulated constituents
in these wastes.
2. What are the Capacity Analysis Results?
This preamble only provides a brief summary of the capacity
analysis performed to support this proposed regulation. For additional
and more detailed information, please refer to the ``Background
Document for Capacity Analysis for Land Disposal Restrictions: Newly
Identified Chlorinated Aliphatics Process Wastes (Proposed Rule), July
1999.''
For this capacity analysis, we examined data on waste
characteristics and management practices gathered for the purpose of
the chlorinated aliphatics hazardous waste listing determination. The
source for these data is primarily the 1992 RCRA Section 3007 survey
and the follow-up survey specific to these wastes conducted in 1997
(see the docket for this proposed regulation for more information on
these survey instruments).
The available data sources indicate that proposed K173 wastes are
predominantly wastewaters, but may exhibit total suspended solids
content greater than 1 percent, such that they would be classified as
nonwastewaters with respect to the LDR requirements (40 CFR 268.2). EPA
has found that most facilities generating proposed K173 manage these
wastes in tank-based systems prior to a permitted discharge to a
surface water or POTW. The non-CBI portions of the Section 3007 survey
responses, as well as other publicly available information, indicate
that certain facilities manage proposed K173 using underground
injection with existing approved no-migration determinations. Proposed
K173 managed by land disposal units may require alternative treatment
if onsite management to meet the LDR standards or alternative onsite
management is not available. EPA expects that sufficient offsite
treatment capacity is available to manage proposed K173 generated by
these facilities. Specifically, EPA estimates that approximately 37
million tons per year of offsite wastewater treatment capacity are
available, which is well above the quantity of proposed K173 generated
by these facilities. Therefore, sufficient commercial capacity exists
to manage proposed K173 from these facilities should the need for
treatment of proposed K173 wastes arise.
As discussed in this section earlier, the LDR treatment standards
become effective essentially at the same time a listing does unless EPA
grants a national capacity variance because of a lack of available
treatment capacity (see RCRA section 3004(h)(2)). Also, RCRA allows
generators to apply for an extension to the LDR effective date on a
case-by-case basis for specific wastes generated at a specific facility
for which there is not adequate capacity (RCRA section 3004(h)(3)). For
those facilities managing proposed K173 wastes, they may choose to meet
treatment standards by onsite or offsite treatment, submit a modified
no-migration petition to include newly listed wastes if necessary, or
transport their wastes to a commercial Class I hazardous disposal well
facility.
Based on EPA's information, the facilities managing proposed K173
wastes by underground injection have existing approved no-migration
determinations. If an injection well has received a no-migration
determination, it can inject a newly prohibited waste if the waste is
similar to wastes included in the initial no-migration petition (63 FR
28626, May 26, 1998). EPA has information showing that the facilities
already manage these newly-proposed K173 wastes in their underground
injection wells. Further, EPA's sampling and analysis results for
wastewater from one of the facilities shows that none of the
constituents being proposed for inclusion in 40 CFR 268.40 for proposed
K173 (i.e., numerical treatment standards) were present at
concentrations greater than the proposed numerical treatment standards.
This suggests that for this facility, the newly-proposed treatment
standards for proposed K173 might already be met.
Based on the available data presented above, EPA is not proposing a
national capacity variance for surface-disposed or underground-injected
proposed K173 wastes. However, EPA recognizes that there are
uncertainties in the available data such that a facility may require
extra time (beyond the effective date) to
[[Page 46524]]
comply with the new listing and land disposal restrictions
requirements, if finalized. For example, EPA realizes that proposed
K173 can be variable in composition and not always exhibit
concentrations below the proposed numerical treatment standards. Also,
any facility with an approved no-migration determination without the
waste already incorporated in the determination may need to submit a
modified petition (40 CFR Part 148.20 (f)). Potentially, the
modification process for the existing no-migration petition, as well as
the permit modification itself, may be time-consuming. There are
potential logistical difficulties associated with accessing available
treatment capacity for wastewater, as well. For example, if a facility
generates high volumes of proposed K173 and cannot manage the waste
onsite in a manner compliant with the LDR standards, they may need to
make considerable logistical adjustments such as repiping, retooling,
and development of transportation networks at the plant in order to
ship the wastewater offsite for treatment or disposal. Additionally,
although commercial treatment or disposal capacity is available, the
logistics of transporting high volumes of wastewater may be
problematic, particularly if existing piping, onsite storage, or
loading are not in place. Should these difficulties arise such that
both onsite and offsite treatment and disposal are not available for
facilities currently using underground injection, EPA will consider all
available data and information provided during the public comment
period and revise its capacity analysis accordingly in making the final
capacity determination.
For K174 wastes, the available data sources indicate that there is
no quantity of the wastewater form of K174 that will require
alternative commercial treatment. There is adequate wastewater
treatment capacity available should the need for treatment of the
wastewater form of K174 arise. From the available data sources,
required alternative treatment capacity for K174 nonwastewater may be
as low as 1,900 tons per year if most generators meet the proposed
requirements for contingent management listing. If the generators do
not manage K174 nonwastewater according to contingent management for
the listing designation, the waste generated must meet LDR standards
before land disposal, and the total quantity requiring treatment may be
up to 106,000 tons per year. As described in the BDAT section above, we
are proposing that numerical treatment standards be applied to K174
nonwastewaters. These standards were derived by estimating the
concentration level following use of combustion technologies. We
estimate that the commercially available sludge and solid combustion
capacity is at least 300,000 tons per year and therefore sufficient to
treat the proposed K174 hazardous waste that would require treatment.
Therefore, EPA is proposing not to grant a capacity variance for K174
nonwastewaters or wastewaters.
For wastes proposed to be listed as K175, the available data
sources indicate that there is no quantity of the wastewater form of
proposed K175 that will require alternative commercial treatment. There
is adequate wastewater treatment capacity available should the need for
treatment of the wastewater form of K175 arise. For nonwastewater form
of proposed K175, EPA estimates that up to 130 tons per year may
require alternative commercial treatment. As described in the BDAT
section above, two options are proposed as the treatment standard. In
one option, the treatment standard was proposed as a technology
standard (RMERC), with residues meeting a concentration level. We have
identified at least one facility that operates commercially and that
potentially can be used for the treatment of wastes proposed to be
listed as K175; there are other treaters which conduct RMERC and the
details are discussed in the Capacity Analysis Background Document. We
recognize that treatment residuals from these wastes may require
additional treatment capacity (e.g., stabilization of the ash following
combustion of the wastes) to achieve the UTS for any metal constituents
that may be present in the residuals. We estimate that there is several
million tons per year of commercial stabilization capacity available.
In the second option for nonwastewater form of proposed K175 described
in the BDAT section above, the treatment standard would be a numerical
standard followed by certain landfill restrictions. EPA expects that
commercial treaters can customize their treatment process to immobilize
the waste, attain a pH of less than 6.0, and meet the treatment
standard. Therefore, sufficient commercial treatment capacity exists
for this proposed K175 hazardous waste. EPA is proposing to not grant a
national capacity variance from LDR treatment standards for
nonwastewater or wastewater forms of proposed K175.
Also, the ultimate volumes of wastes estimated to require
alternative or additional commercial treatment may change if the final
listing determinations change; should this occur, we will revise the
capacity analysis accordingly.
For soil and debris contaminated with these wastes, EPA believes
that the vast majority of contaminated soil and debris contaminated
with these wastes will be managed on site and therefore will not
require substantial commercial treatment capacity. Therefore, we are
not proposing to grant a national capacity variance for hazardous soil
and debris contaminated with the newly listed wastes covered under this
proposal. Based on the 1992 RCRA 3007 Survey questionnaire responses
and 1997 updated responses, there are no data showing mixed radioactive
wastes associated with the proposed listings. We are not proposing to
grant a national capacity variance for mixed radioactive wastes (i.e.,
radioactive wastes mixed with proposed K173, K174, or K175) or soil and
debris contaminated with these mixed radioactive wastes. As discussed
in this section earlier, EPA also is not proposing to grant a national
capacity variance for proposed K173, K174, or K175 wastes being
surface-disposed or underground injected.
EPA requests comments on current and future management practices
and the volumes managed for these wastes. Also, we request comments on
other commercially-available thermal and non-thermal treatment or
recovery capacity that would achieve proposed LDR treatment standards
for these wastes and on chemical and physical constraints of treatment
technologies for the wastes. Specifically, EPA requests comments on its
proposal to not grant a capacity variance for proposed K173 waste. EPA
solicits comments on physical and chemical characteristics of proposed
K173 wastes, any treatment problems before disposing of proposed K173,
the time and necessary procedures required for permit modifications for
proposed K173 generators or commercial treatment or disposal
facilities, required changes for operating practices, and any specific
difficulties in making treatment capacity unavailable that would
warrant a variance. For nonwastewater form of proposed K175, we solicit
any information regarding the availability of RMERC for treating the
wastes, and regarding chemical and physical constraints to meet
numerical standards and pH restriction for this waste.
IV. Compliance Dates
A. Notification
Under RCRA Section 3010 any person generating, transporting, or
managing a hazardous waste must notify EPA (or an authorized State) of
its activities.
[[Page 46525]]
Section 3010(a) allows EPA to waive, under certain circumstances, the
notification requirements under Section 3010 of RCRA. EPA is proposing
to waive the notification requirement as unnecessary for persons
already identified within the hazardous waste management universe
(i.e., persons who have an EPA identification number under 40 CFR
262.12). EPA is not proposing to waive the notification requirement for
waste handlers who have neither notified the Agency that they may
manage hazardous wastes nor received an EPA identification number. Such
individuals will have to provide notification under Section 3010. Any
person who generates, transports, treats, stores, or disposes of these
wastes and has not previously received an EPA identification number,
must do so within 90 days of the effective date of the final rule.
B. Interim Status and Permitted Facilities
Today's proposed rule is being proposed under the authorities
granted to EPA under HSWA. Because HSWA requirements are applicable in
authorized States at the same time as in unauthorized States, EPA will
regulate the newly identified wastes listed under HSWA until States are
authorized to regulate these wastes. Thus, once this regulation becomes
effective as a final rule, EPA will apply Federal regulations to these
wastes and to their management in both authorized and unauthorized
States.
VII. State Authority
A. Applicability of Rule in Authorized States
Under Section 3006 of RCRA, EPA may authorize qualified States to
administer and enforce the RCRA program within the State. (See 40 CFR
Part 271 for the standards and requirements for authorization.)
Following authorization, EPA retains enforcement authority under
Sections 3007, 3008, 3013, and 7003 of RCRA, although authorized States
have primary enforcement responsibility.
Before the Hazardous and Solid Waste Amendments of 1984 (HSWA)
amended RCRA, a State with final authorization administered its
hazardous waste program entirely in lieu of the Federal program in that
State. The Federal requirements no longer applied in the authorized
State, and EPA could not issue permits for any facilities located in
the State with permitting authorization. When new, more stringent
Federal requirements were promulgated or enacted, the State was
obligated to enact equivalent authority within specified time-frames.
New Federal requirements did not take effect in an authorized State
until the State adopted the requirements as State law.
By contrast, under Section 3006(g) of RCRA, 42 U.S.C. 6926(g), new
requirements and prohibitions imposed by the HSWA (including the
hazardous waste listings proposed in this notice) take effect in
authorized States at the same time that they take effect in non-
authorized States. EPA is directed to implement those requirements and
prohibitions in authorized States, including the issuance of permits,
until the State is granted authorization to do so. While States must
still adopt HSWA-related provisions as State law to retain final
authorization, the Federal HSWA requirements apply in authorized States
until the States revise their program and receive authorization for the
revisions.
B. Effect on State Authorizations
Because this proposal (with the exception of the actions proposed
under CERCLA authority) will be promulgated pursuant to the HSWA, a
State submitting a program modification is able to apply to receive
either interim or final authorization under Section 3006(g)(2) or
3006(b), respectively, on the basis of requirements that are
substantially equivalent or equivalent to EPA's requirements. The
procedures and schedule for State program modifications under Section
3006(b) are described in 40 CFR 271.21. It should be noted that all
HSWA interim authorizations are currently scheduled to expire on
January 1, 2003 (see 57 FR 60129, February 18, 1992).
Section 271.21(e)(2) of EPA's State authorization regulations (40
CFR Part 271) requires that states with final authorization modify
their programs to reflect Federal program changes and submit the
modifications to EPA for approval. Once EPA approves the modification,
the State requirements become RCRA subtitle C requirements. Because
this rule would be promulgated pursuant to HSWA, if the proposal is
adopted as a final rule, Table 1 at 40 CFR 271.1 will be amended
accordingly. If finalized, EPA will implement this rule in all States,
including authorized States, until the States modify their authorized
programs to reflect this rule.
VIII. Designation of Chlorinated Aliphatic Wastes (Proposed K173,
K174 and K175) Under the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA)
A. What Is the Relationship Between RCRA and CERCLA?
CERCLA defines the term ``hazardous substance'' to include RCRA
hazardous wastes. When EPA adds a hazardous waste under RCRA, the
Agency also will add the waste to its list of CERCLA hazardous
substances. EPA establishes a reportable quantity or RQ for each CERCLA
hazardous substance. EPA provides a list of the CERCLA hazardous
substances along with their RQs in Table 302.4 at 40 CFR 302.4. If you
are the person in charge of a vessel or facility that releases a CERCLA
hazardous substance in an amount that equals or exceeds its RQ, then
you must report that release to the National Response Center (NRC). You
also may have to notify State and local authorities.
B. Is EPA Proposing To Add Chlorinated Aliphatic Wastes to CERCLA?
Yes. Today, EPA is proposing to add chlorinated aliphatic wastes
(Proposed K173, K174 and K175) to the list of CERCLA hazardous
substances. As discussed below, EPA also proposes to adjust the RQs for
these wastes.
C. How Does EPA Determine Reportable Quantities?
Under CERCLA, all new hazardous substances automatically have a
statutory one-pound RQ. EPA adjusts the RQ of a newly added hazardous
substance based on an evaluation of its intrinsic physical, chemical,
and toxic properties. These intrinsic properties--called ``primary
criteria''--are aquatic toxicity, mammalian toxicity (oral, dermal, and
inhalation), ignitability, reactivity, chronic toxicity, and potential
carcinogenicity. EPA evaluates the data for a hazardous substance for
each primary criterion. To adjust the RQs, EPA ranks each criterion on
a scale that corresponds to an RQ value of 1, 10, 100, 1,000, or 5,000
pounds. For each criterion, EPA establishes a tentative RQ. A hazardous
substance may receive several tentative RQ values based on its
particular intrinsic properties. The lowest of the tentative RQs
becomes the ``primary criteria RQ'' for that substance.
After the primary criteria RQs are assigned, EPA further evaluates
substances for their susceptibility to certain degradative processes.
These are secondary adjustment criteria. The
[[Page 46526]]
natural degradative processes are biodegradation, hydrolysis, and
photolysis (BHP). If a hazardous substance, when released into the
environment, degrades rapidly to a less hazardous form by one or more
of the BHP processes, EPA generally raises its RQ (as determined by the
primary RQ adjustment criteria) by one level. Conversely, if a
hazardous substance degrades to a more hazardous product after its
release, EPA assigns an RQ to the original substance equal to the RQ
for the more hazardous substance.
The standard methodology used to adjust the RQs for RCRA hazardous
waste streams differs from the methodology applied to individual
hazardous substances. The procedure for assigning RQs to RCRA waste
streams is based on the results of an analysis of the hazardous
constituents of the waste streams. The constituents of each RCRA
hazardous waste stream are identified in 40 CFR Part 261, Appendix VII.
EPA first determines an RQ for each hazardous constituent within the
waste stream using the methodology described above. The lowest RQ value
of these constituents becomes the adjusted RQ for the waste stream.
When there are hazardous constituents of a RCRA waste stream that are
not CERCLA hazardous substances, the Agency develops an RQ, called a
``reference RQ,'' for these constituents in order to assign an
appropriate RQ to the waste stream (see 48 FR 23565, May 25, 1983). In
other words, the Agency derives the RQ for waste streams based on the
lowest RQ of all of the hazardous constituents, regardless of whether
they are CERCLA hazardous substances.
D. When Do I Need To Report a Release of Proposed K173, K174 or K175
Under CERCLA?
Today, EPA is proposing to adjust statutory RQs for the proposed
K173, K174 or K175 waste streams to one pound based on their hazardous
constituents. EPA is proposing to adjust the RQ at one pound for the
proposed K173 and K174 waste streams based on their hazardous
constituents, chlorinated dibenzo-p-dioxins (CDDs) and chlorinated
dibenzofurans (CDFs). EPA is proposing to adjust the RQ at one pound
for the proposed K175 waste stream based on its hazardous constituent,
mercury. However, in determining when to report a release of proposed
K173, K174 or K175, EPA is proposing to allow you to apply the mixture
rule, codified in 40 CFR 302.6, using the maximum observed
concentrations of the hazardous constituents within the respective
waste streams.
The mixture rule provides that ``discharges of mixtures and
solutions are subject to RQ regulations only where a component
hazardous substance of the mixture or solution is discharged in a
quantity equal to or greater than its RQ'' (44 FR 50767, August 29,
1979). Therefore, if the concentration of a hazardous constituent is
known, the amount of release needed to reach its RQ can be calculated.
By using the maximum observed concentration that EPA is proposing
today, you may apply the mixture rule, even if you don't know the
concentration of constituents released. That is, if you are the person
in charge, you must immediately report the release as soon as you know
that you have released proposed K173, K174 or K175 in an amount that
will reach the RQ for the waste stream. This approach is reasonable and
conservative because the sampling data presented in the Listing
Background Document accurately identify the maximum observed
concentrations of the hazardous constituents in the chlorinated
aliphatics waste streams. Table VIII-1 below identifies the hazardous
constituents for each waste stream, their maximum observed
concentrations in parts per million (ppm), and their constituents' RQs
or reference RQs.
Table VIII-1.--Maximum Observed Concentration and Corresponding RQ for
Hazardous Constituents That Are Basis for Listing Proposed K173, K174,
and K175
------------------------------------------------------------------------
Max.
Waste Constituent Concentration RQ (lb)
(ppm (mg/kg))
------------------------------------------------------------------------
K173.............. 2,3,7,8-TCDD............. 0.000000017 1
1,2,3,7,8-PeCDD.......... 0.00000015 1
1,2,3,4,7,8-HxCDD........ 0.00000012 1
1,2,3,6,7,8-HxCDD........ 0.00000091 1
1,2,3,7,8,9-HxCDD........ 0.00000092 1
1,2,3,4,6,7,8-HpCDD...... 0.000044 1
OCDD..................... 0.00022 1
2,3,7,8-TCDF............. 0.00000045 1
1,2,3,7,8-PeCDF.......... 0.0000012 1
2,3,4,7,8-PeCDF.......... 0.0000015 1
1,2,3,4,7,8-HxCDF........ 0.000042 1
1,2,3,6,7,8-HxCDF........ 0.000045 1
1,2,3,7,8,9-HxCDF........ 0.000014 1
2,3,4,6,7,8-HxCDF........ 0.000027 1
1,2,3,4,6,7,8-HpCDF...... 0.0013 1
1,2,3,4,7,8,9-HpCDF...... 0.00017 1
OCDF..................... 0.006 1
Chloroform............... 7.1 10
K174.............. 2,3,7,8-TCDD............. 0.000039 1
1,2,3,7,8-PeCDD.......... 0.0000108 1
1,2,3,4,7,8-HxCDD........ 0.000024 1
11,2,3,6,7,8-HxCDD....... 0.000083 1
1,2,3,7,8,9-HxCDD........ 0.000062 1
1,2,3,4,6,7,8-HpCDD...... 0.00123 1
OCDD..................... 0.0129 1
2,3,7,8-TCDF............. 0.000145 1
1,2,3,7,8-PeCDF.......... 0.0000777 1
2,3,4,7,8-PeCDF.......... 0.000127 1
1,2,3,4,7,8-HxCDF........ 0.001425 1
1,2,3,6,7,8-HxCDF........ 0.000281 1
[[Page 46527]]
1,2,3,7,8,9-HxCDF........ 0.00014 1
2,3,4,6,7,8-HxCDF........ 0.000648 1
1,2,3,4,6,7,8-HpCDF...... 0.0207 1
1,2,3,4,7,8,9-HpCDF...... 0.0135 1
OCDF..................... 0.212 1
K175 Mercury.................. 9200 1
------------------------------------------------------------------------
For example, if proposed K173 is released from your facility and
you do not know the actual concentrations of its constituents, you may
assume that the concentrations are those identified in Table VIII-1.
Thus, applying the mixture rule to the assumed maximum concentrations
indicated in the table, you would have to release 1,408,450 pounds to
reach the RQ for this waste (based on the maximum observed
concentration of chloroform). If proposed K174 waste is released from
your facility and you do not know the actual concentrations of its
constituents, you may apply the mixture rule to the assumed maximum
concentrations indicated in the table. You would have to release
4,716,981 pounds of proposed K174 to reach the RQ for this waste (based
on the maximum observed concentration of OCDF). If proposed K175 is
released from your facility and you do not know the actual
concentration of mercury, you may assume that the concentration is 9200
ppm. Applying the mixture rule, you would have to release 108.7 pounds
of this waste to reach the RQ.
E. What if I Know the Concentration of the Constituents in My Waste?
If you know the concentration levels of all the hazardous
constituents in a particular chlorinated aliphatic waste, you may apply
the mixture rule (see 40 CFR 302.6(b)) to the actual concentrations.
You would need to report a release of either waste when an RQ or more
of any of their respective hazardous constituents is released.
F. How Did EPA Determine the RQs for Proposed K173, K174 and K175 and
Their Hazardous Constituents?
The hazardous constituents identified as the basis for listing the
proposed K173 and K174 waste streams include chlorinated dibenzo-p-
dioxins (CDDs) and chlorinated dibenzofurans (CDFs). Previously, EPA
had established an adjusted RQ of one pound for 2,3,7,8-TCDD (see 54 FR
33426). EPA has not established adjusted RQs for the other CDD and CDF
congeners. However, EPA recognizes that a number of these congeners
exhibit dioxin-like toxicity and has established ``reference RQs'' of
one pound for these congeners to support the development of the
adjusted RQs for the proposed K173 and K174 waste streams.
The adjusted RQ for 2,3,7,8-TCDD was established as one pound based
on potential carcinogenicity, considering the weight of evidence that
this substance is carcinogenic, and considering its estimated
carcinogenic potency. To establish reference RQs for the other CDD and
CDF congeners in the waste stream, EPA applied the toxicity equivalency
factors (TEFs) established for dioxin-like compounds to the potency
factor used as the basis for the adjusted RQ for 2,3,7,8-TCDD. Of the
210 CDD and CDF congeners, only those with chlorine substitutions in,
at least, the 2, 3, 7, and 8 positions (a total of 17 CDD and CDF
congeners) are considered to have dioxin-like toxicity. Applying the
TEFs established for these 17 congeners to the potency factor
established for 2,3,7,8-TCDD indicates that all of the congeners fit
into RQ Potency Group 1 with a corresponding reference RQ of one
pound.58 Therefore, because each of the hazardous
constituents has an RQ or reference RQ of one pound, EPA is proposing
to establish an adjusted RQ of one pound for the proposed K173 and K174
waste streams.
---------------------------------------------------------------------------
\58\ For an explanation of how potency factors are calculated
and potency groups and RQs are established, see the Technical
Background Document to Support Rulemaking Pursuant to CERCLA Section
102, Volume 3, July 27, 1989. This document can be viewed by calling
the EPA Superfund Docket Center, 703-603-8917, and requesting
document number 102 RQ 273C.
---------------------------------------------------------------------------
The hazardous constituent identified as the basis for proposing to
list the K175 waste stream is mercury. Previously, EPA had established
an adjusted RQ of one pound for mercury (see 50 FR 13456, April 4,
1985). Because the hazardous constituent used as the basis for listing
the K175 waste stream has an RQ of one pound, EPA is proposing to
establish an adjusted RQ of one pound for this waste.
G. How Do I Report a Release?
To report a release of proposed K173, K174 or K175 (or any other
CERCLA hazardous substance) that equals or exceeds its RQ, you must
immediately notify the National Response Center (NRC) as soon as you
have knowledge of that release. The toll-free telephone number of the
NRC is 1-800-424-8802; in the Washington, DC, metropolitan area, the
number is (202) 267-2675.
You also may have to notify State and local authorities. The
Emergency Planning and Community Right-to-Know Act (EPCRA) requires
that owners and operators of certain facilities report releases of
CERCLA hazardous substances and EPCRA extremely hazardous substances
(see list in 40 CFR Part 355, Appendix A) to State and local
authorities. After the release of an RQ or more of any of those
substances, you must report immediately to the community emergency
coordinator of the local emergency planning committee for any area
likely to be affected by the release, and to the State emergency
response commission of any State likely to be affected by the release.
H. What Is the Statutory Authority for This Program?
Section 101(14) of CERCLA defines the term hazardous substance by
referring to substances listed under several other environmental
statutes, as well as those substances that EPA designates as hazardous
under CERCLA Section 102(a). In particular, CERCLA Section 101(14)(C)
defines the term hazardous substance to include ``any hazardous waste
having the characteristics identified under or listed pursuant to
Section 3001 of the Solid Waste Disposal Act.'' CERCLA Section 102(a)
gives EPA authority to establish RQs for CERCLA hazardous substances.
CERCLA Section 103(a) requires any person in charge of a vessel or
facility that releases a CERCLA hazardous substance in an amount equal
to or
[[Page 46528]]
greater than its RQ to report the release immediately to the federal
government. EPCRA Section 304 requires owners or operators of certain
facilities to report releases of CERCLA hazardous substances and EPCRA
extremely hazardous substances to State and local authorities.
I. How Can I Influence EPA's Thinking on Regulating Proposed K173, K174
and K175 Under CERCLA?
In developing this proposal, EPA tried to address the concerns of
all our stakeholders. Your comments will help us to improve this
proposal. We invite you to provide your views on this proposal and how
it may affect you. We also are interested in receiving any comments
that you have on the information provided in Table VIII-1, including
the hazardous constituents identified for proposed K173, K174 and K175
and the maximum observed concentrations for each constituent.
IX. Administrative Assessments
A. Executive Order 12866
Under Executive Order 12866 (September 30, 1993), EPA must
determine whether a regulatory action is ``significant'' and,
therefore, subject to OMB review and the other provisions of the
Executive Order. A significant regulatory action is defined by
Executive Order 12866 as one that may:
(1) Have an annual effect on the economy of $100 million or more
or adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or
communities;
(2) Create a serious inconsistency or otherwise interfere with
an action taken or planned by another agency;
(3) Materially alter the budgetary impact of entitlements,
grants, user fees, or loan programs or rights and obligations or
recipients thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
Executive Order 12866.
Pursuant to the terms of Executive Order 12866, EPA has determined that
this rule is a ``significant regulatory action'' because of point four
(4) above: The rule raises two novel legal or policy issues arising out
of legal mandates, the President's priorities, or the principles set
forth in this Executive Order. Today's proposed rule, which includes
proposed alternative listing approaches for two wastestreams deviates
from the Agency's standard or historic listing approach in the
following two ways:
Targeted wastestream listing: Historically, the
Agency's listing program captured entire quantities of targeted
wastestream posing unacceptable risks to human health and the
environment. Today's proposed listing approach for two wastestreams
(i.e., EDC/VCM wastewater treatment sludges and one alternative
option for VCM-A wastewater treatment sludges) proposes listing as
hazardous only those quantities of the waste that are managed in a
manner that reflects unacceptable risks.
Wastewater treatment units: In addition, today's action
proposes to change a long-standing Agency policy of exempting from
RCRA regulation the management of hazardous wastes in wastewater
treatment units regulated under Sec. 402 or Sec. 307(b) of the Clean
Water Act. To address the risks associated with the wastewaters
proposed to be listed as hazardous under today's action, the Agency
believes that it is necessary to regulate these management units
when used to manage chlorinate aliphatic wastewaters, to ensure
against hazardous air emissions from this wastestream. (In section
III.E.1.a.vi. of today's preamble, EPA is requesting comment on this
approach.)
Due to the Agency's decision to propose a deviation from our historical
hazardous waste listing approach and to change our long-standing policy
regarding the regulation of wastewater treatment units, the Agency is
deeming today's action to be ``significant'' and is submitting these
proposed policy changes to OMB for review. Changes made to the Agency's
proposed actions in response to OMB suggestions or recommendations are
documented in the public record.
Although today's proposed rule is not ``economically significant,''
the Agency prepared an ``Economic Background Document'' in support of
today's rule. The Agency's economic assessment addresses, among other
factors, industry compliance costs, industry financial impacts, and
potential for small entity impacts. A summary of findings from our
economic assessment is presented in Section IV. The complete Economic
Background Document is available for public review from the RCRA
docket, according to instructions provided in the introduction to this
preamble.
B. Regulatory Flexibility Act
Pursuant to the 1980 Regulatory Flexibility Act (RFA) (5 U.S.C. 601
et seq., as amended by the Small Business Regulatory Enforcement
Fairness Act (SBREFA) of 1996), whenever an agency is required to
publish a notice of rulemaking for any proposed or final rule, it must
prepare and make available for public comment, a regulatory flexibility
analysis that describes the effect of the rule on small entities (i.e.,
small businesses, small organizations, and small governmental
jurisdictions). However, regulatory flexibility analysis is not
required if the head of an agency certifies that the rule will not have
a ``significant'' economic impact on a substantial number of small
entities.
SBREFA amended the Regulatory Flexibility Act to require Federal
agencies to provide a statement of the factual basis for certifying
that a rule will not have a ``significant'' economic impact on a
substantial number of small entities. The following discussion explains
EPA's determination.
EPA has examined this rule's potential effects on small entities as
required by the RFA/SBREFA, and has determined that this action will
not have a significant economic impact on a substantial number of small
entities. This is evidenced by the fact that only one of the
potentially affected, parent companies determined to be producers of
chlorinated aliphatic products in the U.S., may be classified as a
``small business,'' according to the U.S. Small Business
Administration's employee size standards (i.e., less than or equal to
1,000 employees) and according to that company's primary Standard
Industrial Classification (SIC) code (SIC 2869).
I hereby certify that this rule will not have a significant
economic impact on a substantial number of small entities. This rule,
therefore, does not require a regulatory flexibility analysis.
C. Paperwork Reduction Act
The information collection requirements in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An
Information Collection Request (ICR) document was prepared by EPA (ICR
No. 1924.01) and a copy may be obtained from Sandy Farmer by mail at OP
Regulatory Information Division; U.S. Environmental Protection Agency
(2137); 401 M Street, S.W.; Washington, D.C. 20460, by E-mail at
farmer.sandy@epamail.epa.gov, or by calling (202) 260-2740. A copy also
may be downloaded off the Internet at http://www.epa.gov/icr.
This proposed rule includes new information collection requirements
subject to OMB review under the Paperwork Reduction Act of 1995, 44
U.S.C. 3501 et seq. In addition to complying with the existing subtitle
C recordkeeping and reporting requirements for the newly listed waste
streams, EPA is proposing that facilities generating chlorinated
aliphatic wastewaters comply with testing requirements. In conjunction
with testing requirements, we are proposing that generators maintain
documentation of detailed standard operating procedures for the
sampling and
[[Page 46529]]
analysis protocols that were employed, sensitivity and bias of the
measurement process, precision of the results, and the analytical
results from testing events. These requirements are being proposed to
ensure generators are complying with the proposed technical standards
for controlling air emissions of dioxins from wastewater treatment
tanks.
EPA also is proposing that generators be able to document their
compliance with the conditions provided for exclusion from the scope of
the two conditional hazardous waste listings proposed in today's
notice. This requirement is necessary to ensure that both EDC/VCM
wastewater treatment sludges and VCM-A wastewater treatment sludges are
managed in a manner that is safe for human health and the environment.
In addition, EPA is requiring' disposal facilities that manage VCM-A
wastewater treatment sludges to maintain records documenting that these
sludges are co-disposed only with other wastes that have a pH level of
6.0 or lower. This requirement is necessary to ensure that the mercury
contained in the waste does not leach from the waste after disposal.
The Agency estimated the burden associated with complying with the
requirements in this proposed rule. Included in the ICR are the burden
estimates for the following requirements for industry respondents:
reading the regulations; performing testing and waste analyses; keeping
records of testing results; completing and submitting certifications;
incorporating testing and waste analysis requirements into permits;
keeping records documenting compliance with conditions for exclusion
from hazardous waste listings; and keeping records documenting
compliance with landfill waste disposal requirements for the disposal
of VCM-A wastewater treatment sludges. Included also are the burden
estimates for State respondents for applying for State authorization.
The Agency determined that all of this information is necessary to
ensure compliance with today's proposed rule.
To the extent that this rule imposes any information collection
requirements under existing RCRA regulations promulgated in previous
rulemakings, those requirements have been approved by the Office of
Management and Budget (OMB) under the Paperwork Reduction Act, 44
U.S.C. 3501 et seq., and have been assigned OMB control numbers 2050-
0009 (ICR No. 1573, Part B Permit Application, Permit Modifications,
and Special Permits); 2050-0120 (ICR No. 1571, General Facility
Hazardous Waste Standards); 2050-0028 (ICR No. 261, Notification of
Hazardous Waste Activity); 2050-0034 (ICR No. 262, RCRA Hazardous Waste
Permit Application and Modification, Part A); 2050-0039 (ICR No. 801,
Requirements for Generators, Transporters, and Waste Management
Facilities under the Hazardous Waste Manifest System); 2050-0035 (ICR
No. 820, Hazardous Waste Generator Standards); and 2050-0024 (ICR No.
976, 1997 Hazardous Waste Report).
EPA estimates that the projected annual hour burden for industry
respondents will be 1,088 hours, and cost of $184,186. Total estimates
over three years are 3,264 hours and $552,558.
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes the time
needed to review instructions; develop, acquire, install, and use
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.
Comments are requested on the Agency's need for this information,
the accuracy of the provided burden estimates, and any suggested
methods for minimizing respondent burden, including through the use of
automated collection techniques. Send comments on the ICR to the
Director, OP Regulatory Information Division; U.S. Environmental
Protection Agency (2137); 401 M Street, S.W.; Washington, D.C. 20460;
and to the Office of Information and Regulatory Affairs, Office of
Management and Budget, 725 17th Street, N.W.; Washington, D.C. 20503,
marked ``Attention: Desk Officer for EPA.'' Include the ICR number in
any correspondence. Since OMB is required to make a decision concerning
the ICR between 30 and 60 days after August 25, 1999, a comment to OMB
is best assured of having its full effect if OMB receives it by
September 24, 1999. The final rule will respond to any OMB and public
comments on the information collection requirements contained in this
proposal.
D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Pub.
L. 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under Section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures by State, local, and tribal governments, in
the aggregate, or by the private sector, of $100 million or more in any
one year. Before promulgating an EPA rule for which a written statement
is needed, Section 205 of the UMRA generally requires EPA to identify
and consider a reasonable number of regulatory alternatives and adopt
the least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule. The provisions of Section 205
do not apply when they are inconsistent with applicable law. Moreover,
Section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted. Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
governments, including tribal governments, it must have developed under
Section 203 of the UMRA a small government agency plan. The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements.
The Agency's analysis for compliance with the UMRA found that the
proposed action imposes less than the $100 million expenditure
threshold on the private sector; thus, today's rule is not subject to
the requirements of Sections 202 and 205 of UMRA.
E. Executive Order 12875: Enhancing the Intergovernmental Partnership
Under Executive Order 12875, EPA may not issue a regulation that is
not required by statute and that creates a mandate upon a State, local
or tribal government, unless the Federal government provides the funds
[[Page 46530]]
necessary to pay the direct compliance costs incurred by those
governments, or EPA consults with those governments. If EPA complies by
consulting, Executive Order 12875 requires EPA to provide to the Office
of Management and Budget a description of the extent of EPA's prior
consultation with representatives of affected State, local and tribal
governments, the nature of their concerns, any written communications
from the governments, and a statement supporting the need to issue the
regulation. In addition, Executive Order 12875 requires EPA to develop
an effective process permitting elected officials and other
representatives of State, local and tribal governments ``to provide
meaningful and timely input in the development of regulatory proposals
containing significant unfunded mandates.''
F. Executive Order 13084: Consultation and Coordination With Indian
Tribal Governments
Under Executive Order 13084, EPA may not issue a regulation that is
not required by statute, that significantly or uniquely affects the
communities of Indian tribal governments, and that imposes substantial
direct compliance costs on those communities, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by the tribal governments, or EPA consults with those
governments. If EPA complies by consulting, Executive Order 13084
requires EPA to provide to the Office of Management and Budget, in a
separately identified section of the preamble to the rule, a
description of the extent of EPA's prior consultation with
representatives of affected tribal governments, a summary of the nature
of their concerns, and a statement supporting the need to issue the
regulation. In addition, Executive Order 13084 requires EPA to develop
an effective process permitting elected officials and other
representatives of Indian tribal governments ``to provide meaningful
and timely input in the development of regulatory policies on matters
that significantly or uniquely affect their communities.''
Today's rule does not significantly or uniquely affect the
communities of Indian tribal governments. There is no impact to tribal
governments as the result of the proposed action. In addition, this
proposed rule is required by statute (HSWA). Accordingly, the
requirements of Section 3(b) of Executive Order 13084 do not apply to
this rule.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
Executive Order 13045, ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997), applies
to any rule that: (1) is determined to be ``economically significant''
as defined under E.O. 12866, and (2) concerns an environmental health
or safety risk that EPA has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the Agency must evaluate the environmental health or
safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency. This
proposed rule is not subject to the Executive Order because it is not
economically significant as defined in E.O. 12866, and because the
Agency does not have reason to believe the environmental health or
safety risks addressed by this action present a disproportionate risk
to children.
The topic of environmental threats to children's health is growing
in regulatory importance as scientists, policy makers, and village
leaders continue to recognize the extent to which children are
particularly vulnerable to environmental hazards. Recent EPA actions
have been in the forefront of addressing environmental threats to the
health and safety of children. Today's proposed rule further reflects
our commitment to mitigating environmental threats to children.
A few significant physiological characteristics are largely
responsible for children's increased susceptibility to environmental
hazards. First, children eat proportionately more food, drink
proportionately more fluids, and breathe more air per pound of body
weight than do adults. As a result, children potentially experience
greater levels of exposure to environmental threats than do adults.
Second, because children's bodies are still in the process of
development, their immune systems, neurological systems, and other
immature organs can be more easily and considerably affected by
environmental hazards.
Today's proposed rule will reduce risks posed by the hazardous
constituents found in the listed waste streams by requiring more
appropriate and safer management practices. EPA considered risks to
children in its risk assessment. The more appropriate and safer
management practices proposed in this rule are projected to reduce
risks to children potentially exposed to the constituents of concern.
The public is invited to submit or identify peer-reviewed studies and
data, of which the agency may not be aware, that assess results of
early life exposure to the proposed hazardous constituents from
wastewaters and wastewater treatment sludges from the production of
chlorinated aliphatic chemicals.
H. National Technology Transfer and Advancement Act of 1995
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Pub. L. No. 104-113, Section 12(d) (15 U.S.C.
272 note) directs EPA to use voluntary consensus standards in its
regulatory activities, unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standards bodies. The NTTAA directs EPA
to provide Congress, through OMB, explanations when the Agency decides
not to use available and applicable voluntary consensus standards.
This proposed rulemaking does not involve technical standards.
Therefore, EPA is not considering the use of any voluntary consensus
standards.
I. Executive Order 12898: Environmental Justice
Under Executive Order 12898, ``Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations,'' as well as through EPA's April 1995, ``Environmental
Justice Strategy, OSWER Environmental Justice Task Force Action Agenda
Report,'' and National Environmental Justice Advisory Council, EPA has
undertaken to incorporate environmental justice into its policies and
programs. EPA is committed to addressing environmental justice
concerns, and is assuming a leadership role in environmental justice
initiatives to enhance environmental quality for all residents of the
United States. The Agency's goals are to ensure that no segment of the
population, regardless of race, color, national origin, or income,
bears disproportionately high and adverse human health and
environmental effects as a result of EPA's policies, programs, and
activities.
Today's proposed rule is intended to reduce risks of hazardous
wastes as proposed, and to benefit all populations. As such, this rule
is not expected to cause any disproportionately high and adverse
impacts to minority or low-
[[Page 46531]]
income communities versus non-minority or affluent communities.
In making hazardous waste listing determinations, we base our
evaluations of potential risk from the generation and management of
solid wastes on an analysis of potential individual risk. In conducting
risk evaluations, our goal is to estimate potential risk to any
population of potentially exposed individuals (e.g., home gardeners,
adult farmers, children of farmers, anglers) located in the vicinity of
any generator or facility handling a waste. Therefore, we are not
putting poor, rural, or minority populations at any disadvantage with
regard to our evaluation of risk or with regard to how the Agency makes
its proposed hazardous waste listing determinations.
In proposing today to list three wastes as hazardous (i.e.,
chlorinated aliphatic wastewaters, EDC/VCM wastewater treatment sludges
managed in land treatment units, and VCM-A wastewater treatment
sludges), all populations potentially exposed to these wastes or
potentially exposed to releases of the hazardous constituents in the
wastes will benefit from the proposed listing determination. In
addition, listing determinations are effected at the national level.
The wastes proposed to be listed as hazardous will be hazardous
regardless of where they are generated and regardless of where they may
be managed. Although the Agency understands that the proposed listing
determinations, if finalized, may affect where these wastes are managed
in the future (in that hazardous wastes must be managed at subtitle C
facilities), the Agency's decision to list these wastes as hazardous is
independent of any decisions regarding the location of waste generators
and the siting of waste management facilities.
Similarly, in cases where the Agency is proposing not list a solid
waste as hazardous because the waste does not meet the criteria for
being identified as a hazardous waste, these decisions are based upon
an evaluation of potential individual risks located in proximity to any
facility handling the waste. In the case of wastewater treatment
sludges from the production of allyl chloride and methyl chloride and
the case of EDC/VCM wastewater treatment sludges managed in landfills,
we believe the potential risk levels associated with the wastes are
safe for all populations potentially exposed to the wastes and their
constituents.
The Agency is soliciting comment and input from all stakeholders,
including members of the environmental justice community and members of
the regulated community. We encourage all interested parties to provide
comments or further information related to potential environmental
justice concerns or impacts, including information and data on
facilities that have evaluated potential ecological and human health
impacts (taking into account subsistence patterns and sensitive
populations) to minority or low-income communities.
List of Subjects
40 CFR Part 148
Administrative practice and procedure, Hazardous waste, Reporting
and recordkeeping requirements, Water supply.
40 CFR Part 261
Environmental protection, Hazardous materials, Recycling, Waste
treatment and disposal.
40 CFR Part 264
Environmental protection, Air pollution control, Hazardous waste,
Insurance, Packaging and containers, Reporting and recordkeeping
requirements, Security measures, Surety bonds.
40 CFR Part 265
Air pollution control, Hazardous waste, Insurance, Packaging and
containers, Reporting and recordkeeping requirements, Security
measures, Surety bonds, Water supply.
40 CFR Part 268
Environmental protection, Hazardous materials, Reporting and
recordkeeping requirements, Waste management.
40 CFR Part 271
Environmental protection, Administrative practice and procedure,
Confidential business information, Hazardous material transportation,
Hazardous waste, Indians-lands, Intergovernmental relations, Penalties,
Reporting and recordkeeping requirements, Water pollution control,
Water supply.
40 CFR Part 302
Environmental protection, Air pollution control, Chemicals,
Hazardous chemicals, Hazardous materials, Hazardous materials
transportation, Hazardous substances, Hazardous waste,
Intergovernmental relations, Natural resources, Reporting and
recordkeeping requirements, Superfund, Waste treatment and disposal,
Water pollution control, Water supply.
Dated: July 30, 1999.
Carol M. Browner,
Administrator.
For the reasons set forth in the preamble, title 40, chapter I of
the Code of Federal Regulations is proposed to be amended as follows:
PART 148--HAZARDOUS WASTE INJECTION RESTRICTIONS
1. The authority citation for part 148 continues to read as
follows:
Authority: Sec. 3004, Resource Conservation and Recovery Act, 42
U.S.C. 6901 et seq.
2. Section 148.18 is amended by adding paragraphs (l) and (m) to
read as follows:
Sec. 148.18 Waste-specific prohibitions--newly listed and identified
wastes.
* * * * *
(l) Effective [date six months after publication of final rule],
the wastes specified in 40 CFR 261.32 as EPA Hazardous Waste Numbers
K173, K174, and K175 are prohibited from underground injection.
(m) The requirements of paragraphs (a) through (l) of this section
do not apply:
(1) If the wastes meet or are treated to meet the applicable
standards specified in subpart D of part 268 of this chapter; or
(2) If an exemption from a prohibition has been granted in response
to a petition under subpart C of this part; or
(3) During the period of extension of the applicable effective
date, if an extension has been granted under Sec. 148.4.
PART 261--IDENTIFICATION AND LISTING OF HAZARDOUS WASTE
3. The authority citation for part 261 continues to read as
follows:
Authority: 42 U.S.C. 6905, 6912(a), 6921, 6922, 6924(y), and
6938.
4. Section 261.3 is amended by adding a paragraph (c)(2)(ii)(F) to
read as follows:
Sec. 261.3 Definition of hazardous waste.
* * * * *
(c) * * *
(2) * * *
(ii) * * *
(F) Wastewater treatment sludges derived from the treatment of
chlorinated aliphatic wastewaters listed in Sec. 261.32 as EPA
Hazardous Waste No. K173. However, this paragraph does not exempt from
the definition of hazardous waste any wastewater treatment sludges that
are explicity listed (e.g., K174, K175) or that meet any other listing
in
[[Page 46532]]
subpart D of this part, as a result of the derived-from rule.
* * * * *
5. Section 261.4 is amended by revising paragraph (b)(15) to read
as follows:
Sec. 261.4 Exclusions.
* * * * *
(b) * * *
(15) Leachate or gas condensate collected from landfills where
certain solid wastes have been disposed, provided that:
(i) The solid wastes disposed would meet one or more of the listing
descriptions for Hazardous Waste Codes K169, K170, K171, K172, K174,
and K175 if these wastes had been generated after the effective date of
the listing;
(ii) The solid wastes described in paragraph (b)(15)(i) of this
section were disposed prior to the effective date of the listing:
(iii) The leachate or gas condensate do not exhibit any
characteristic of hazardous waste nor are derived from any other listed
hazardous waste;
(iv) Discharge of the leachate or gas condensate, including
leachate or gas condensate transferred from the landfill to a POTW by
truck, rail, or dedicated pipe, is subject to regulation under Sections
307(b) or 402 of the Clean Water Act.
(v) After February 13, 2001, leachate or gas condensate derived
from K169-K172 will no longer be exempt if it is stored or managed in a
surface impoundment prior to discharge. After [date 24 months after
publication date of the final rule], leachate or gas condensate derived
from K175 will no longer be exempt if it is stored or managed in a
surface impoundment prior to discharge. There is one exception: if the
surface impoundment is used to temporarily store leachate or gas
condensate in response to an emergency situation (e.g., shutdown of
wastewater treatment system), provided the impoundment has a double
liner, and provided the leachate or gas condensate is removed from the
impoundment and continues to be managed in compliance with the
conditions of this paragraph (b)(15)(v) after the emergency ends.
* * * * *
6. In Sec. 261.32, the table is amended by adding in alphanumeric
order (by the first column) the following waste streams to the subgroup
``Organic Chemicals'' to read as follows:
Sec. 261.32 Hazardous waste from specific sources.
* * * * *
------------------------------------------------------------------------
Industry and EPA hazardous
waste No. Hazardous waste Hazard code
------------------------------------------------------------------------
* * * *
* * *
Organic Chemicals:
* * * *
* * *
K173.................. Wastewaters from the (T)
production of
chlorinated aliphatic
hydrocarbons, except
wastewaters generated
from the production of
vinyl chloride monomer
using mercuric chloride
catalyst in an acetylene-
based process. This
listing includes
wastewaters from the
production of
chlorinated aliphatic
hydrocarbons having
carbon chain lengths
ranging from one to and
including five, with
varying amounts and
positions of chlorine
substitution.
K174.................. Wastewater treatment (T)
sludges from the
production of ethylene
dichloride or vinyl
chloride monomer
(including sludges that
result from commingled
ethylene dichloride or
vinyl chloride monomer
wastewater and other
wastewater), unless the
sludges meet the
following conditions:
they are disposed of in
a subtitle C or D
landfill licensed or
permitted by the state
or federal government;
they are not otherwise
placed on the land prior
to final disposal; and
the generator maintains
documentation
demonstrating that the
waste was either
disposed of in an on-
site landfill or
consigned to a
transporter or disposal
facility that provided a
written commitment to
dispose of the waste in
an off-site landfill.
Respondents in any
action brought to
enforce the requirements
of subtitle C must, upon
a showing by the
government that the
respondent managed
wastewater treatment
sludges from the
production of vinyl
chloride monomer or
ethylene dichloride,
demonstrate that they
meet the terms of the
exclusion set forth
above. In doing so, they
must provide appropriate
documentation (e.g.,
contracts between the
generator and the
landfill owner/operator,
invoices documenting
delivery of waste to
landfill, etc.) that the
terms of the exclusion
were met.
K175.................. Option 1: Wastewater (T)
treatment sludges from
the production of vinyl
chloride monomer using
mercuric chloride
catalyst in an acetylene-
based process.
Option 2: Wastewater (T)
treatment sludges from
the production of vinyl
chloride monomer using
mercuric chloride
catalyst in an acetylene-
based process, unless
the sludges are disposed
in a subtitle C
landfill; and the
sludges do not fail the
toxicity characteristic
for mercury in 40 CFR
261.24; and the
generator maintains
documentation
demonstrating that the
waste was disposed of in
a subtitle C landfill or
consigned to a
transporter or disposal
facility that provided a
written commitment to
dispose of the waste in
a subtitle C landfill.
Respondents in any
action brought to
enforce the requirements
of subtitle C must, upon
a showing by the
government that the
respondent managed
wastewater treatment
sludges from the
production of vinyl
chloride monomer using
mercuric chloride
catalyst in an acetylene-
based process,
demonstrate that they
meet the terms of the
exclusion set forth
above. In doing so, they
must provide appropriate
documentation (e.g.,
contracts between the
generator and the
landfill owner/operator,
invoices documenting
delivery of waste to
landfill, analytical
results or other
information showing the
waste does not fail the
toxicity characteristic
for mercury, etc.) that
the terms of the
exclusion were met.
* * * *
* * *
------------------------------------------------------------------------
7. Appendix VII to Part 261 is amended by adding the following
wastestreams in alphanumeric order (by the first column) to read as
follows:
[[Page 46533]]
Appendix VII to Part 261--Basis for Listing Hazardous Waste
------------------------------------------------------------------------
EPA hazardous waste No. Hazardous constituents for which listed
------------------------------------------------------------------------
* * * *
* * *
K173..................... 1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin
(1,2,3,4,6,7,8-HpCDD), 1,2,3,4,6,7,8-
Heptachlorodibenzofuran (1,2,3,4,6,7,8,-
HpCDF), 1,2,3,4,7,8,9-
Heptachlorodibenzofuran (1,2,3,6,7,8,9-
HpCDF), HxCDDs (All Hexachlorodibenzo-p-
dioxins), HxCDFs (All
Hexachlorodibenzofurans), PeCDDs (All
Pentachlorodibenzo-p-dioxins), OCDD
(1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin,
OCDF (1,2,3,4,6,7,8,9-
Octachlorodibenzofuran), PeCDFs (All
Pentachlorodibenzofurans), TCDDs (All
tetrachlorodi-benzo-p-dioxins), TCDFs (All
tetrachlorodibenzofurans).
K174..................... 1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin
(1,2,3,4,6,7,8-HpCDD), 1,2,3,4,6,7,8-
Heptachlorodibenzofuran (1,2,3,4,6,7,8,-
HpCDF), 1,2,3,4,7,8,9-
Heptachlorodibenzofuran (1,2,3,6,7,8,9-
HpCDF), HxCDDs (All Hexachlorodibenzo-p-
dioxins), HxCDFs (All
Hexachlorodibenzofurans), PeCDDs (All
Pentachlorodibenzo-p-dioxins), OCDD
(1,2,3,4,6,7,8,9-Octachlorodibenzo-p-dioxin,
OCDF (1,2,3,4,6,7,8,9-
Octachlorodibenzofuran) PeCDFs (All
Pentachlorodibenzofurans), TCDDs (All
tetrachlorodi-benzo-p-dioxins), TCDFs (All
tetrachlorodibenzofurans).
K175..................... Mercury
------------------------------------------------------------------------
8. Appendix VIII to part 261 is amended by adding in alphabetical
sequence of common name the following entries:
Appendix VIII to Part 261--Hazardous Constituents
----------------------------------------------------------------------------------------------------------------
Chemical Hazardous
Common name Chemical abstracts name abstracts No. waste No.
----------------------------------------------------------------------------------------------------------------
* * * * * *
*
Octachlorodibenzo-p-dioxin (OCDD)............. 1,2,3,4,6,7,8,9- 3268-87-9 ..............
Octachlorodibenzo-p-dioxin.
Octachlorodibenzofuran (OCDF)................. 1,2,3,4,6,7,8,9- 39001-02-0 ..............
Octachlorodibenzofuran.
* * * * * *
*
----------------------------------------------------------------------------------------------------------------
PART 264--STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE
TREATMENT, STORAGE, AND DISPOSAL FACILITIES
9. The authority citation for part 264 continues to read as
follows:
Authority: 42 U.S.C. 6905, 6912(a), 6924, and 6925.
Subpart A--General
10. Section 264.1 is amended by adding a sentence to the end of
paragraph (g)(6) to read as follows:
Sec. 264.1 Purpose, scope and applicability.
* * * * *
(g) * * *
(6) * * * However, if the owner or operator is managing EPA
Hazardous Waste No. K173 (chlorinated aliphatic wastewater) in a tank,
the owner/operator must comply with Sec. 264.1080(h).
* * * * *
Subpart CC--Air Emission Standards for Tanks, Surface Impoundments,
and Containers
11. Section 264.1080 is amended by adding paragraph (h) to read as
follows:
Sec. 264.1080 Applicability.
* * * * *
(h) Notwithstanding the applicability requirements in paragraph (a)
of this section, any tank (including wastewater treatment units as
defined in Sec. 260.10 of this chapter) managing EPA Hazardous Waste
No. K173, where the dioxin concentration in the influent wastewater to
the tank is greater than or equal to 1 ng/L TCDD TEQ at a 95% upper
confidence limit around the mean, must comply with the requirements of
this paragraph, and with Sec. 264.1084 as appropriate. In order to
determine whether the influent concentration of EPA Hazardous Waste No.
K173 is greater than or equal to 1 ng/L TCDD TEQ at a 95% upper
confidence limit around the mean, the generator or owner/operator must
comply with the requirements in 40 CFR 265.1080(h)(1) through (5).
PART 265--INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF
HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES
12. The authority citation for part 265 continues to read as
follows:
Authority: 42 U.S.C. 6905, 6906, 6912, 6922, 6923, 6924, 6925,
6935, 6936, and 6937, unless otherwise noted.
Subpart A--General
13. Section 265.1 is amended by adding a sentence to the end of
paragraph (c)(10) to read as follows:
Sec. 265.1 Purpose, scope, and applicability.
* * * * *
(c) * * *
(10) * * * However, if the owner or operator is managing EPA
Hazardous Waste No. K173 (chlorinated aliphatic wastewater) in a tank,
the owner/operator must comply with Sec. 265.1080(h).
* * * * *
Subpart CC--Air Emission Standards for Tanks, Surface Impoundments,
and Containers
14. Section 265.1080 is amended by adding paragraph (h) to read as
follows:
Sec. 265.1080 Applicability
* * * * *
(h) Notwithstanding the applicability requirements in paragraph (a)
of this section, any tank (including wastewater treatment units as
defined in Sec. 260.10 of this chapter) managing EPA Hazardous Waste
No. K173, where the dioxin concentration in the influent wastewater to
the tank is equal to or greater than 1 ng/L TCDD TEQ at a 95% upper
confidence limit around the mean, must
[[Page 46534]]
comply with the requirements of this paragraph, and with Sec. 265.1085
as appropriate. In order to determine whether the influent
concentration of EPA Hazardous Waste No. K173 is greater than or equal
to 1 ng/L TCDD TEQ at a 95% upper confidence limit around the mean, the
generator or owner/operator must comply with the following:
(1) Waste sampling and analysis plans. (i) General. The generator
of K173 shall develop and follow a written waste sampling and analysis
plan which describes the procedures for sampling and analysis of the
hazardous waste at the influent to each wastewater treatment tank to be
excluded from the requirements of this part. The waste sampling and
analysis plan shall be developed in accordance with the applicable
sections of the ``Test Methods for Evaluating Solid Waste, Physical/
Chemical Methods'' (SW-846) or other appropriate guidance. The plan
shall be followed and retained at the facility claiming an exemption
for one or more wastewater treatment tanks.
(ii) At a minimum, the plan must include:
(A) A detailed description of the test method(s) used to test for
2,3,7,8-substituted chlorinated dibenzo-p-dioxin (CDD) and 2,3,7,8-
substituted chlorinated dibenzo-p-furan (CDF) congeners;
(B) The sampling method used to obtain representative samples of
each wastewater tank influent; and
(C) How the design of the sampling program accounts for any
expected fluctuations in concentrations over time, while ensuring that
the samples collected are grab samples and that all samples are
collected within a timeframe that will allow for the analyses to
account for potential variabilities in the wastestream.
(2) Sampling and analysis. (i) General. For each wastewater
treatment tank for which an exemption is claimed, the generator of K173
must:
(A) Test for all 2,3,7,8-substituted CDDs/CDFs; or
(B) Use process knowledge for tanks downstream of a tank that is
exempt as a result of testing specified in paragraph (h)(2)(i)(A) of
this section.
(ii) The K173 generator may use any reliable analytical method to
demonstrate that the TCDD TEQ does not exceed the trigger level. It is
the responsibility of the generator to ensure that the sampling and
analysis are unbiased, precise, and representative of the waste.
(iii) The generator must ensure that the measurements are
sufficiently sensitive, accurate and precise to demonstrate that the
maximum TCDD TEQ in any sample analyzed does not exceed the specified
trigger level.
(iv) For the tank to be eligible for exemption, a generator must
demonstrate that:
(A) The maximum TCDD TEQ in the influent to the tank does not
exceed 1 ng/L at the 95% upper confidence limit around the mean;
(B) The TCDD TEQ for each sample shall be determined by multiplying
the concentration of any 2,3,7,8-substituted CDD or CDF detected and
the appropriate toxicity equivalency factor (TEF), as described below,
and summing these products for each sample;
(C) The following toxicity equivalence factors shall be used:
------------------------------------------------------------------------
Compound WHO-TEF
------------------------------------------------------------------------
2,3,7,8-TetraCDD............................................ 1
1,2,3,7,8-PentaCDD.......................................... 1
1,2,3,4,7,8-HexaCDD......................................... 0.1
1,2,3,7,8,9-HexaCDD......................................... 0.1
1,2,3,6,7,8-HexaCDD......................................... 0.1
1,2,3,4,6,7,8-HeptaCDD...................................... 0.01
1,2,3,4,5,7,8,9-OctaCDD..................................... 0.0001
2,3,7,8-TetraCDF............................................ 0.1
2,3,4,7,8-PentaCDF.......................................... 0.5
1,2,3,7,8-PentaCDF.......................................... 0.05
1,2,3,4,7,8-HexaCDF......................................... 0.1
1,2,3,7,8,9-HexaCDF......................................... 0.1
1,2,3,6,7,8-HexaCDF......................................... 0.1
2,3,4,6,7,8-HexaCDF......................................... 0.1
1,2,3,4,7,8,9-HeptaCDF...................................... 0.01
1,2,3,4,6,7,8-HeptaCDF...................................... 0.01
1,2,3,4,6,7,8,9-OctaCDF..................................... 0.0001
------------------------------------------------------------------------
(D) The analysis could have detected the presence of the CDD/CDF
congeners at or below the trigger level of 1 ng/L at the 95% upper
confidence limit around the mean.
(v) In an enforcement action, the burden of proof to establish
conformance with the exemption specification shall be on the generator
claiming the exclusion.
(vi) The generator must conduct sampling and analysis in accordance
with their waste sampling and analysis plan developed under paragraph
(h)(1) of this section.
(vii) The influent to exempt wastewater treatment tanks must be re-
tested, at a minimum, annually and must be retested after a process
change that could change the TCDD TEQ level in the waste.
(3) Records. The generator must maintain records of the following
information on-site:
(i) All information required to be submitted to the implementing
authority as part of the notification of the claim:
(A) The owner/operator name, address, and RCRA facility ID number
of the person claiming the exemption; and
(B) The certification signed by the person claiming the exclusion
or his authorized representative.
(ii) A brief description of the tanks covered by the claimed
exemption, including dimensions and service in the wastewater treatment
system;
(iii) A description and process flow diagram of the wastewater
treatment system, clearly identifying the exempt tanks and sampling
points;
(iv) The results of all analyses and all detection limits achieved
as required under paragraph (h)(2) of this section;
(v) The waste sampling and analysis plan;
(vi) The results of the sampling and analysis, including the
following:
(A) The dates and times waste samples were obtained, and the dates
the samples were analyzed;
(B) The names and qualifications of the person(s) who obtained the
samples;
(C) A description of the temporal and spatial locations of the
samples;
(D) The name and address of the laboratory facility at which
analyses of the samples were performed;
(E) A detailed description of the analytical methods used,
including any clean-up and sample preparation methods;
(F) All quantitation limits achieved and all other quality control
results for the analysis (including method blanks, duplicate analyses,
matrix spikes, etc.), laboratory quality assurance data, and
description of any deviations from analytical methods written in the
plan or from any other activity written in the plan which occurred;
(G) All laboratory analytical results demonstrating that the
trigger exemption level has not been exceeded at the tank influent, for
each exempt tank; and
(H) All laboratory documentation that support the analytical
results, unless a contract between the claimant and the laboratory
provides for the documentation to be maintained by the laboratory for
the period specified in paragraph (h)(4) of this section and also
provides for the availability of the documentation to the claimant upon
request; and
(4) Records retention. Records must be maintained for the period of
three years. A generator must maintain a current waste sampling and
analysis plan during that three year period.
(5) Notification and certification. The waste generator must submit
a one-time notification and certification to the EPA Region or an
authorized State (by mail or delivery service which provides return
receipt) within 60 days following the effective date of the final rule
or initial use of a wastewater treatment
[[Page 46535]]
tank used to manage K173. The notification must include the waste
generator's name and address, a representative's name and telephone
number, and a description of the wastewater treatment system and the
assessed tanks. The certification must be signed by an authorized
representative and must state as follows:
I certify under penalty of law that the influent(s) to the tanks
identified in this certification do not exceed 1 ng/L TCDD TEQ. I am
aware that there are significant penalties for submitting a false,
inaccurate, or incomplete certification, including the possibility
of fine and imprisonment.
PART 268--LAND DISPOSAL RESTRICTIONS
15. The authority citation for part 268 continues to read as
follows:
Authority: 42 U.S.C. 6905, 6912(a), 6921, and 6924.
Subpart A--General
16. Section 268.7 is amended by adding paragraph (f) to read as
follows:
Sec. 268.7 Testing, tracking, and recordkeeping requirements for
generators, treaters, and disposal facilities.
* * * * *
(f) The owner or operator of a facility codisposing wastes with
wastes identified as hazardous waste K175 must maintain records
available for inspection of the pH of the wastes so codisposed.
Subpart C--Prohibitions on Land Disposal
17. Section 268.33 is revised to read as follows:
Sec. 268.33 Waste specific prohibitions--chlorinated aliphatic wastes.
(a) Effective [date 90 days from date of publication of final
rule], the wastes specified in 40 CFR Part 261 as EPA Hazardous Wastes
Numbers K173, K174, and K175, and soil and debris contaminated with
these wastes are prohibited from land disposal.
(b) Effective [date two years from date of publication of final
rule], the following wastes are prohibited from land disposal: soil and
debris contaminated with radioactive wastes mixed with EPA Hazardous
wastes K173, K174, and K175.
(c) Between [date of publication of final rule] and [Insert date
two years from date of publication of final rule], radioactive waste
mixed with K173, K174, and K175 wastes and/or soil and debris may be
disposed in a landfill or surface impoundment only if such unit is in
compliance with the requirements specified in Sec. 268.5(h)(2).
(d) The requirements of paragraphs (a), (b) and (c) of this section
do not apply if:
(1) The wastes meet the applicable treatment standards specified in
subpart D of this part;
(2) Persons have been granted an exemption from a prohibition
pursuant to a petition under Sec. 268.6, with respect to those wastes
and units covered by the petition;
(3) The wastes meet the applicable treatment standards established
pursuant to a petition granted under Sec. 268.44;
(4) Hazardous debris has met the treatment standards in Sec. 268.40
or the alternative treatment standards in Sec. 268.45; or
(5) Persons have been granted an extension to the effective date of
a prohibition pursuant to Sec. 268.5, with respect to these wastes
covered by the extension.
(e) To determine whether a hazardous waste identified in this
section exceeds the applicable treatment standards specified in
Sec. 268.40, the initial generator must test a sample of the waste
extract or the entire waste, depending on whether the treatment
standards are expressed as concentrations in the waste extract or the
waste, or the generator may use knowledge of the waste. If the waste
contains regulated constituents in excess of the applicable Universal
Treatment Standard levels of Sec. 268.48, the waste is prohibited from
land disposal, and all requirements of this part are applicable, except
as otherwise specified.
(f) Disposal of K175 wastes containing mercuric sulfide is
restricted to units to which disposal of wastes in excess of pH 6.0 is
prohibited.
18. In Sec. 268.40, the Table is amended in the entry for F039 to
add constituents in alphabetical order and by adding in alphanumeric
order new entries for K173, K174, and K175 to read as follows:
Sec. 268.40 Applicability of treatment standards.
* * * * *
Treatment Standards for Hazardous Wastes
----------------------------------------------------------------------------------------------------------------
Regulated hazardous constituent Wastewaters Nonwastewaters
---------------------------------------------------------------------------
Waste description and Concentration Concentration in mg/
Waste code treatment/regulatory in mg/L,\3\ or kg \5\ unless noted
subcategory \1\ Common name CAS \2\ No. technology as ``mg/L TCLP'', or
code \4\ technology code
----------------------------------------------------------------------------------------------------------------
* * * * * *
*
F039......... Leachate (liquids 1,2,3,4,6,7,8- 35822-39-4 0.000035 0.0025
that have percolated Heptachlorodibenzo-
through land p-dioxin
disposed wastes) (1,2,3,4,6,7,8-
resulting from the HpCDD).
disposal of more
than one restricted
waste classified as
hazardous under
Subpart D of this
part. (Leachate
resulting from the
disposal of one or
more of the
following EPA
Hazardous Wastes and
no other Hazardous
Waste retains its
EPA Hazardous Waste
Number(s): F020,
F021, F022, F026,
F027, and/or F028) *
* *.
................... 1,2,3,4,6,7,8- 67562-39-4 0.000035 0.0025
Heptachlorodibenzof
uran (1,2,3,4,6,7,8-
HpCDF).
................... 1,2,3,4,7,8,9- 55673-89-7 0.000035 0.0025
Heptachlorodibenzof
uran (1,2,3,4,7,8,9-
HpCDF).
[[Page 46536]]
* * * * * *
*
1,2,3,4,6,7,8,9- 3268-87-9 0.000063 0.0025
Octachlorodibenzo-p-
dioxin (OCDD).
1,2,3,4,6,7,8,9- 39001-02-0 0.000063 0.005
Octachlorodibenzofu
ran (OCDF).
* * * * * *
*
K173......... Wastewaters from the Bis(2- 111-44-4 0.033 6.0
production of chloroethyl)ether.
chlorinated
aliphatic
hydrocarbons, except
wastewaters
generated from the
production of vinyl
chloride monomer
using mercuric
chloride catalyst in
an acetylene-based
process. This
listing includes
wastewaters from the
production of
chlorinated
aliphatic
hydrocarbons having
carbon chain lengths
ranging from one to
and including five,
with varying amounts
and positions of
chlorine
substitution.
Chloroform.......... 67-66-3 0.046 6.0
Pentachlorophenol... 87-86-5 0.089 7.4
Phenol.............. 108-95-4 0.039 6.2
2,4,6- 88-06-2 0.035 7.4
Trichlorophenol.
1,2,3,4,6,7,8- 35822-39-4 0.000035 0.0025
Heptachlorodibenzo-
p-dioxin
(1,2,3,4,6,7,8-
HpCDD).
1,2,3,4,6,7,8- 67562-39-4 0.000035 0.0025
Heptachlorodibenzof
uran (1,2,3,4,6,7,8-
HpCDF).
1,2,3,4,7,8,9- 55673-89-7 0.000035 0.0025
Heptachlorodibenzof
uran (1,2,3,4,7,8,9-
HpCDF).
HxCDDs (All 0.000063 0.001
Hexachloro-.
dibenzo-p-dioxins)
34465-46-8.
HxCDFs (All 55684-94-1 0.000063 0.001
Hexachloro-.
dibenzofurans)......
1,2,3,4,6,7,8,9- 3268-87-9 0.000063 0.005
Octachlorodibenzo-p-
dioxin (OCDD).
1,2,3,4,6,7,8,9- 39001-02-0 0.000063 0.005
Octachlorodibenzofu
ran (OCDF).
PeCDDs (All 36088-22-9 0.000063 0.001
Pentachloro-.
dibenzo-p-dioxins)..
PeCDFs (All 30402-15-4 0.000035 0.001
Pentachloro-.
dibenzofurans)......
TCDDs (All 0.000063 0.001
tetrachloro-.
di-benzo-p-dioxins)
41903-57-5.
TCDFs (All 55722-27-5 0.000063 0.001
tetrachloro-.
dibenzofurans)......
Chromium (Total).... 7440-47-3 2.77 0.60 mg/L TCLP
Nickel.............. 7440-02-0 3.98 11 mg/L TCLP
K174......... Wastewater treatment 1,2,3,4,6,7,8- 35822-39-4 0.000035 0.0025
sludges from the Heptachlorodibenzo-
production of p-dioxin
ethylene dichloride (1,2,3,4,6,7,8-
or vinyl chloride HpCDD).
monomer.
1,2,3,4,6,7,8- 67562-39-4 0.000035 0.0025
Heptachlorodibenzof
uran (1,2,3,4,6,7,8-
HpCDF).
1,2,3,4,7,8,9- 55673-89-7 0.000035 0.0025
Heptachlorodibenzof
uran (1,2,3,4,7,8,9-
HpCDF).
HxCDDs (All 34465-46-8 0.000063 0.001
Hexachloro-.
dibenzo-p-dioxins)..
HxCDFs (All 55684-94-1 0.000063 0.001
Hexachloro-.
dibenzofurans)......
1,2,3,4,6,7,8,9- 3268-87-9 0.000063 0.005
Octachlorodibenzo-p-
dioxin (OCDD).
1,2,3,4,6,7,8,9- 39001-02-0 0.000063 0.005
Octachlorodibenzofu
ran (OCDF).
[[Page 46537]]
PeCDDs (All 36088-22-9 0.000063 0.001
Pentachloro-.
dibenzo-p-dioxins)..
PeCDFs (All 30402-15-4 0.000035 0.001
Pentachloro-.
dibenzofurans)......
TCDDs (All 41903-57-5 0.000063 0.001
tetrachlorodi-benzo-
p-dioxins).
TCDFs (All 55722-27-5 0.000063 0.001
tetrachlorodibenzof
urans).
Arsenic............. 7440-36-0 1.4 5.0 mg/L TCLP
K175......... K175 (wastewater Mercury............. 7438-97-6 NA RMERC
treatment sludge
from the production
of vinyl chloride
monomer using
mercuric chloride
catalyst in an
acetylene-based
process)
nonwastewaters that
contain greater than
or equal to 260 mg/
kg total mercury.
K175 nonwastewaters Mercury............. 7438-97-6 NA 0.20 mg/L TCLP
that contain less
than 260 mg/kg total
mercury that are
residues from RMERC.
Other K175 Mercury............. 7438-97-6 NA 0.025 mg/L TCLP
nonwastewaters that
contain less than
260 mg/kg total
mercury and are not
residues from RMERC.
pH.................. .............. NA pH <6.0 all="" k175="" wastewaters.="" mercury.............="" 7438-97-6="" 0.15="" na="" *="" *="" *="" *="" *="" *="" *="" ----------------------------------------------------------------------------------------------------------------="" *="" note:="" na="" means="" not="" applicable.="" \1\="" the="" waste="" descriptions="" provided="" in="" this="" table="" do="" not="" replace="" waste="" descriptions="" in="" 40="" cfr="" part="" 261.="" descriptions="" of="" treatment/regulatory="" subcategories="" are="" provided,="" as="" needed,="" to="" distinguish="" between="" applicability="" of="" different="" standards.="" \2\="" cas="" means="" chemical="" abstract="" services.="" when="" the="" waste="" code="" and/or="" regulated="" constituents="" are="" described="" as="" a="" combination="" of="" a="" chemical="" with="" its="" salts="" and/or="" esters,="" the="" cas="" number="" is="" given="" for="" the="" parent="" compound="" only.="" \3\="" concentration="" standards="" for="" wastewaters="" are="" expressed="" in="" mg/l="" and="" are="" based="" on="" analysis="" of="" composite="" samples.="" \4\="" all="" treatment="" standards="" expressed="" as="" a="" technology="" code="" or="" combination="" of="" technology="" codes="" are="" explained="" in="" detail="" in="" 40="" cfr="" 268.42="" table="" 1-technology="" codes="" and="" descriptions="" of="" technology-based="" standards.="" \5\="" except="" for="" metals="" (ep="" or="" tclp)="" and="" cyanides="" (total="" and="" amenable)="" the="" nonwastewater="" treatment="" standards="" expressed="" as="" a="" concentration="" were="" established,="" in="" part,="" based="" upon="" incineration="" in="" units="" operated="" in="" accordance="" with="" the="" technical="" requirements="" of="" 40="" cfr="" part="" 264="" subpart="" o="" or="" part="" 265="" subpart="" o,="" or="" based="" upon="" combustion="" in="" fuel="" substitution="" units="" operating="" in="" accordance="" with="" applicable="" technical="" requirements.="" a="" facility="" may="" comply="" with="" these="" treatment="" standards="" according="" to="" provisions="" in="" 40="" cfr="" 268.40(d).="" all="" concentration="" standards="" for="" nonwastewaters="" are="" based="" on="" analysis="" of="" grab="" samples.="" 19.="" in="" sec.="" 268.48(a)="" the="" table="" is="" amended="" by="" adding="" in="" alphabetical="" order="" the="" following="" entries="" under="" the="" heading="" organic="" constituents:="" (the="" footnotes="" are="" republished="" without="" change.)="" sec.="" 268.48="" universal="" treatment="" standards.="" (a)="" *="" *="" *="" universal="" treatment="" standards="" ----------------------------------------------------------------------------------------------------------------="" nonwastewater="" standard="" wastewater="" concentration="" regulated="" constituent="" common="" name="" cas="" \1\="" number="" standard="" in="" mg/kg="" \3\="" concentration="" unless="" noted="" in="" mg/l="" \2\="" as="" ``mg/l="" tclp''="" ----------------------------------------------------------------------------------------------------------------="" *="" *="" *="" *="" *="" *="" *="" 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin="" (1,2,3,4,6,7,8-hpcdd).="" 35822-39-4="" 0.000035="" 0.0025="" 1,2,3,4,6,7,8-heptachlorodibenzofuran="" (1,2,3,4,6,7,8-hpcdf).....="" 67562-39-4="" 0.000035="" 0.0025="" 1,2,3,4,7,8,9-heptachlorodibenzofuran="" (1,2,3,6,7,8,9-hpcdf).....="" 55673-89-7="" 0.000035="" 0.0025="" *="" *="" *="" *="" *="" *="" *="" 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin="" (ocdd)...............="" 3268-87-9="" 0.000063="" 0.005="" 1,2,3,4,6,7,8,9-octachlorodibenzofuran="" (ocdf)...................="" 39001-02-0="" 0.000063="" 0.005="" *="" *="" *="" *="" *="" *="" *="" [[page="" 46538]]="" ----------------------------------------------------------------------------------------------------------------="" *="" note:="" na="" means="" not="" applicable.="" \1\="" cas="" means="" chemical="" abstract="" services.="" when="" the="" waste="" code="" and/or="" regulated="" constituents="" are="" described="" as="" a="" combination="" of="" a="" chemical="" with="" its="" salts="" and/or="" esters,="" the="" cas="" number="" is="" given="" for="" the="" parent="" compound="" only.="" \2\="" concentration="" standards="" for="" wastewaters="" are="" expressed="" in="" mg/l="" and="" are="" based="" on="" analysis="" of="" composite="" samples.="" \3\="" except="" for="" metals="" (ep="" or="" tclp)="" and="" cyanides="" (total="" and="" amenable)="" the="" nonwastewater="" treatment="" standards="" expressed="" as="" a="" concentration="" were="" established,="" in="" part,="" based="" upon="" incineration="" in="" units="" operated="" in="" accordance="" with="" the="" technical="" requirements="" of="" 40="" cfr="" part="" 264,="" subpart="" o,="" or="" part="" 265,="" subpart="" o,="" or="" based="" upon="" combustion="" in="" fuel="" substitution="" units="" operating="" in="" accordance="" with="" applicable="" technical="" requirements.="" a="" facility="" may="" comply="" with="" these="" treatment="" standards="" according="" to="" provisions="" in="" 40="" cfr="" 268.40(d).="" all="" concentration="" standards="" for="" nonwastewaters="" are="" based="" on="" analysis="" of="" grab="" samples.="" *="" *="" *="" *="" *="" part="" 271--requirements="" for="" authorization="" of="" state="" hazardous="" waste="" programs="" 20.="" the="" authority="" citation="" for="" part="" 271="" continues="" to="" read="" as="" follows:="" authority:="" 42="" u.s.c.="" 6905,="" 6912(a),="" and="" 6926.="" 21.="" section="" 271.1(j)="" is="" amended="" by="" adding="" the="" following="" entries="" to="" table="" 1="" and="" table="" 2="" in="" chronological="" order="" by="" date="" to="" read="" as="" follows.="" sec.="" 271.1="" purpose="" and="" scope.="" *="" *="" *="" *="" *="" (j)="" *="" *="" *="" table="" 1.--regulations="" implementing="" the="" hazardous="" and="" solid="" waste="" amendments="" of="" 1984="" ------------------------------------------------------------------------="" title="" of="" federal="" register="" promulgation="" date="" regulation="" reference="" effective="" date="" ------------------------------------------------------------------------="" *="" *="" *="" *="" *="" *="" *="" [insert="" date="" of="" listing="" of="" [insert="" federal="" [insert="" signature="" of="" hazardous="" wastes="" register="" page="" effective="" date="" final="" rule]="" k173,="" k174,="" and="" numbers]="" of="" final="" rule]="" k175="" *="" *="" *="" *="" *="" *="" *="" ------------------------------------------------------------------------="" table="" 2.--self="" implementing="" provisions="" of="" the="" solid="" waste="" amendments="" of="" 1984="" ----------------------------------------------------------------------------------------------------------------="" federal="" register="" effective="" date="" self-implementing="" provision="" rcra="" citation="" reference="" ----------------------------------------------------------------------------------------------------------------="" *="" *="" *="" *="" *="" *="" *="" [effective="" date="" of="" prohibition="" on="" land="" disposal="" of="" k173,="" 3004(g)(4)(c)="" and="" [date="" of="" publication="" final="" rule].="" k174,="" and="" k175="" wastes,="" and="" prohibition="" 3004(m).="" of="" final="" rule],="" [fr="" on="" land="" disposal="" of="" radioactive="" waste="" page="" numbers].="" mixed="" with="" k173,="" k174,="" and="" k175="" wastes,="" including="" soil="" and="" debris.="" *="" *="" *="" *="" *="" *="" *="" ----------------------------------------------------------------------------------------------------------------="" part="" 302--designation,="" reportable="" quantities,="" and="" notification="" 22.="" the="" authority="" citation="" for="" part="" 302="" continues="" to="" read="" as="" follows:="" authority:="" 42="" u.s.c.="" 9602,="" 9603,="" and="" 9604;="" 33="" u.s.c.="" 1321="" and="" 1361.="" 23.="" in="" sec.="" 302.4,="" table="" 302.4="" is="" amended="" by="" adding="" the="" following="" new="" entries="" in="" alphanumeric="" order="" at="" the="" end="" of="" the="" table="" to="" read="" as="" follows:="" sec.="" 302.4="" designation="" of="" hazardous="" substances="" *="" *="" *="" *="" *="" table="" 302.4--list="" of="" hazardous="" substances="" and="" reportable="" quantities="" [note:="" all="" comments/notes="" are="" located="" at="" the="" end="" of="" this="" table]="" --------------------------------------------------------------------------------------------------------------------------------------------------------="" statutory="" final="" rq="" -----------------------------------------------------------------------------="" hazardous="" substance="" casrn="" regulatory="" synonyms="" pounds="" rq="" code="" rcra="" waste="" no.="" category="" (kg)="">-------------------------------------------------------
K173 f............................... ......... ........................ *1 4 K173 X 1(0.454)
K174 f............................... ......... ........................ *1 4 K174 X 1(0.454)
K175 f............................... ......... ........................ *1 4 K175 X 1(0.454)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Indicates the statutory sources as defined by 1, 2, 3, and 4 below.
* * * * *
4--Indicates that the statutory source for designation of this hazardous substance under CERCLA is RCRA Section 3001.
*1--Indicates that the 1-pound RQ is a CERCLA statutory RQ.
* * * * *
f See 40 CFR 302.6(b)(1) for application of the mixture rule to this hazardous waste.
[[Page 46539]]
24. Section 302.6 is amended by revising paragraph (b)(1)(iii)
introductory text and by adding entries K173, K174, and K175 to the
table in paragraph (b)(1)(iii) in numerical order to read as follows:
Sec. 302.6 Notification requirements.
* * * * *
(b) * * *
(1) * * *
(iii) For waste streams K169, K170, K171, K172, K173, K174, and
K175, knowledge of the quantity of all of the hazardous constituent(s)
may be assumed, based on the following maximum observed constituent
concentrations identified by EPA:
------------------------------------------------------------------------
Waste Constituent Max ppm
------------------------------------------------------------------------
* * * *
* * *
K173...................... 2,3,7,8-TCDD.............. 0.000000017
1,2,3,7,8-PeCDD........... 0.00000015
1,2,3,4,7,8-HxCDD......... 0.00000012
1,2,3,6,7,8-HxCDD......... 0.00000091
1,2,3,7,8,9-HxCDD......... 0.00000092
1,2,3,4,6,7,8-HpCDD....... 0.000044
OCDD...................... 0.00022
2,3,7,8-TCDF.............. 0.00000045
1,2,3,7,8-PeCDF........... 0.0000012
2,3,4,7,8-PeCDF........... 0.0000015
1,2,3,4,7,8-HxCDF......... 0.000042
1,2,3,6,7,8-HxCDF......... 0.000045
1,2,3,7,8,9-HxCDF......... 0.000014
2,3,4,6,7,8-HxCDF......... 0.000027
1,2,3,4,6,7,8-HpCDF....... 0.0013
1,2,3,4,7,8,9-HpCDF....... 0.00017
OCDF...................... 0.006
Chloroform................ 7.1
K174...................... 2,3,7,8-TCDD.............. 0.000039
1,2,3,7,8-PeCDD........... 0.0000108
1,2,3,4,7,8-HxCDD......... 0.0000241
1,2,3,6,7,8-HxCDD......... 0.000083
1,2,3,7,8,9-HxCDD......... 0.000062
1,2,3,4,6,7,8-HpCDD....... 0.00123
OCDD...................... 0.0129
2,3,7,8-TCDF.............. 0.000145
1,2,3,7,8-PeCDF........... 0.0000777
2,3,4,7,8-PeCDF........... 0.000127
1,2,3,4,7,8-HxCDF......... 0.001425
1,2,3,6,7,8-HxCDF......... 0.000281
1,2,3,7,8,9-HxCDF......... 0.00014
2,3,4,6,7,8-HxCDF......... 0.000648
1,2,3,4,6,7,8-HpCDF....... 0.0207
1,2,3,4,7,8,9-HpCDF....... 0.0135
OCDF...................... 0.212
K175...................... Mercury................... 9200
------------------------------------------------------------------------
* * * * *
[FR Doc. 99-20753 Filed 8-24-99; 8:45 am]
BILLING CODE 6560-50-P
