[Federal Register Volume 61, Number 42 (Friday, March 1, 1996)]
[Notices]
[Pages 8186-8203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-4963]
[[Page 8185]]
_______________________________________________________________________
Part VI
Environmental Protection Agency
_______________________________________________________________________
Cyanazine; Notice of Preliminary Determination To Terminate Special
Review; Notice of Receipt of Requests for Voluntary Cancellation;
Notice
Federal Register / Vol. 61, No. 42 / Friday, March 1, 1996 /
Notices
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[[Page 8186]]
ENVIRONMENTAL PROTECTION AGENCY
[OPP-30000/60A; FRL-5352-6]
Cyanazine; Notice of Preliminary Determination to Terminate
Special Review; Notice of Receipt of Requests for Voluntary
Cancellation
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of Preliminary Determination to Terminate Special
Review; Announcement of Receipt of Voluntary Cancellation.
Summary: This Notice sets forth EPA's preliminary determination to
terminate the Special Review of cyanazine based on amendments to the
terms and conditions of cyanazine registrations. In effect, the terms
and conditions call for an incremental phaseout and voluntary
cancellation of all pesticide products containing cyanazine that are
registered for use in the United States. The Agency has concluded that,
based on these terms and conditions of the amended registration of
cyanazine, any unreasonable adverse effects posed by cyanazine use will
be eliminated by the phaseout and voluntary cancellation of the
chemical. The Agency concludes that the benefits of use of the chemical
for the limited period of time and in strict accordance with all of the
terms and conditions of registration, outweigh the risks. In making
this determination, the Agency considered the risks and benefits of
cyanazine use in the 7-year phaseout, during which maximum label rates
will be reduced and closed cab application equipment will be required,
as well as the risks and benefits associated with the ultimate
cancellation of all use of cyanazine. In addition, pursuant to section
6(f)(1) of the Federal Insecticide, Fungicide, and Rodenticide Act
(FIFRA), this Notice announces EPA's receipt of requests to voluntarily
cancel all registrations containing cyanazine, effective December 31,
1999.
Dates: Comments, data and information relevant to the Agency's proposed
decision must be received on or before April 1, 1996.
ADDRESS: Submit three copies of written comments bearing the document
number [30000/60A]. By mail to: Public Response and Program Resources
Branch, Field Operations Division (7506C), Office of Pesticide
Programs, Environmental Protection Agency, 401 M St., SW., Washington,
DC 20460. In person, bring comments to Room 1132, CM #2, 1921 Jefferson
Davis Highway, Arlington, VA, Telephone: 703-305-5805.
Comments and data may also be submitted electronically by sending
electronic mail (e-mail) to: opp-docket@epamail.epa.gov. Electronic
comments must be submitted as an ASCII file avoiding the use of special
characters and any form of encryption. Comments and data will also be
accepted on disks in WordPerfect in 5.1 file format or ASCII file
format. All comments and data in electronic form must be identified by
the docket number ``OPP-30000/60A.'' No Confidential Business
Information (CBI) should be submitted through e-mail. Electronic
comments on this document may be filed online at many Federal
Depository Libraries. Additional information on electronic submissions
can be found in Unit IX. of this document.
Information submitted as a comment concerning this document may be
claimed confidential by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. A copy of the comment that
does not contain CBI must be submitted for inclusion in the public
record. Information not marked confidential may be disclosed publicly
by EPA without prior notice. All written comments will be available for
public inspection in Rm. 1132 at the Virginia address given above from
8 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays.
FOR FURTHER INFORMATION CONTACT: By mail: Joseph E. Bailey, Review
Manager, Special Review and Reregistration Division (7508W), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. Office location, telephone number, and e-mail
address: Special Review Branch, 3rd Floor, Crystal Station, 2800
Jefferson Davis Highway, Arlington, VA, Telephone: 703-308-8173, e-
mail: bailey.joseph@epamail.epa.gov. For a copy of documents in the
public docket, to request information concerning the Special Review, or
to request indices to the Special Review public docket, contact the
Public Response and Program Resources Branch, Field Operations Division
(7506C), Office of Pesticide Programs, Environmental Protection Agency,
401 M St., SW., Washington, DC 20460, Telephone: 703-305-5805.
Supplementary Information:
I. Introduction
A. Regulatory Background
Cyanazine is the common name for [2-((4-chloro-6-(ethylamino)-s-
triazine-2-yl)amino)-2-methylpropionitrile], an herbicide sold under
the tradenames of Bladex and Cynex that is available as a granular or
liquid formulation. It is classified as a ``Restricted Use Pesticide''
based on its reproductive effects and detection in ground and surface
water. Cyanazine was first registered by Shell Chemical Company in
1971. Today, DuPont Agricultural Products and Griffin Corporation are
the only registrants of technical grade cyanazine. Ciba Plant
Protection also has one registered product, a mixture of cyanazine and
metalochlor, but submitted a request for voluntary cancellation of this
product which was announced in the Federal Register of November 8, 1995
(60 FR 56333) (Ref. 1). A final cancellation order for this product was
effective February 8, 1996.
In April 1985, a Special Review of cyanazine was initiated based on
studies indicating developmental toxicity in two species after oral
administration of the chemical. The Agency was concerned about
potential risks to mixer/loaders and applicators exposed to cyanazine.
Additional dermal developmental toxicity studies that were submitted to
the Agency led to a refinement of the risk estimates. The Special
Review was concluded in 1988 by requiring personal protective equipment
and revised label language.
The Agency continued to assess ground and surface water monitoring
data for cyanazine contamination and, to help address contamination
concerns, approved label amendments in 1993 that reduced maximum
application rates and required surface water setbacks. These
amendments, however, did not ameliorate all of the Agency's risk
concerns and on February 8, 1994, a preliminary notification letter was
issued to all cyanazine registrants indicating that the Agency was
considering initiating a Special Review of cyanazine because of
potential cancer risks from dietary (food and drinking water) and non-
dietary exposure. Additionally, the Agency was also concerned about
possible ecological risks to nontarget organisms (aquatic organisms,
terrestrial plants) and their ecosystems that may result from the use
of cyanazine.
On November 10, 1994, EPA issued the Notice of Initiation of
Special Review (Position Document 1 or PD 1) formally announcing that a
Special Review was being initiated for cyanazine, along with atrazine
and simazine (58 FR 60412) (Ref. 2). The Agency formally initiated the
Special Review based only on the cancer risk concern to humans. The
Agency remains concerned about possible
[[Page 8187]]
ecological effects; however, these effects were not considered as
formal criteria to initiate the Special Review.
On August 2, 1995, DuPont voluntarily proposed to amend its
cyanazine registrations to effectively phaseout the production of
cyanazine for use in the U.S. by the end of 1999, with incremental
reductions in maximum label application rates in 1997, 1998, and 1999
and a closed cab requirement for applicators beginning in 1998 (Ref.
3). Cyanazine products that have been released for shipment by a
registrant on or before December 31, 1999, may only be distributed and
sold in the channels of trade in accordance with their labels through
September 30, 2002. Such products may only be used through December 31,
2002. EPA accepted DuPont's proposal to amend its cyanazine
registrations. Since the acceptance of DuPont's proposal to amend
cyanazine registrations, EPA has granted new conditional cyanazine
registrations to Griffin based on Griffin's agreement to accept the
same terms and conditions as part of its cyanazine registrations (Refs.
4, 5, 6, 7, and 8).
The Agency has evaluated the risks and benefits posed by the terms
and conditions of the phaseout and voluntary cancellations submitted by
the manufacturers of cyanazine and approved by EPA. Among the factors
considered were the risks of use during and after the phaseout period
and arising from use of existing stocks, the benefits that will accrue
from use during the phaseout and use of existing stocks, the incentives
for and likelihood of the development of alternative control strategies
of a phaseout as opposed to an immediate commencement of cancellation
proceedings, and the litigative risks and uncertainties attendant to a
contested regulatory action as opposed to a voluntary action. Taking
all of these factors into consideration, the Agency has concluded that
risks associated with the proposed voluntary phaseout and cancellation
are outweighed by its benefits. Accordingly, the Agency believes the
Special Review of cyanazine may be terminated on the basis of the
voluntary cancellation.
In response to the triazine PD 1 issued in November 1994, the
Agency received a number of comments about the risks and benefits of
cyanazine. All of the issues raised in the cyanazine comments received
during the comment period are addressed in this Notice and are on file
in the triazine public docket (OPP-30000/60). While a number of the
comments challenged the Agency's decision to initiate the Special
Review of the triazines and questioned various components of the
Agency's assessments, no additional scientific data were received by
the Agency that change the Agency's previous conclusions about
potential risks from cyanazine exposure. The majority of the comments
received were undocumented testimonials that generally made claims
concerning the usefulness of cyanazine. A few commenters provided
additional ground and surface water monitoring data. All of the
comments relating to cyanazine benefits have been considered in
assessing the economic impacts of phasing out cyanazine. Similarly, all
of the comments relating to cyanazine risks have been considered in
assessing the risks associated with the phaseout of cyanazine.
Significant comments and the Agency's responses to the comments are
discussed in appropriate sections of this Notice. Supporting
documentation may be found in the cyanazine public docket (OPP-30000/
60).
As discussed above, the Agency has recently granted cyanazine
conditional registrations to Griffin Corporation. These recently-
approved cyanazine registrations, as well as any others that may be
granted by the Agency in the future, are required to comply with all of
the same terms and conditions of registration for cyanazine as approved
by the Agency for DuPont's registrations. The Griffin products were
conditionally registered by the Agency provided that Griffin comply
with all of the same terms and conditions of the DuPont cyanazine
registrations. If Griffin does not comply with the same terms and
conditions of the cyanazine registration, its registrations are subject
to cancellation by the Agency in accordance with FIFRA section 6(e).
Griffin's release for shipment of its products containing cyanazine
constitutes acceptance of the terms and conditions of the
registrations. In accordance with FIFRA section 3(c)(7)(A), these
conditional registrations have been approved because the Agency has
determined that they are substantially similar to other currently
registered cyanazine products or differ only in ways that do not
significantly increase the risk of unreasonable adverse effects to the
environment.
B. Legal Background
In order to obtain a registration for a pesticide under FIFRA, an
applicant must demonstrate that the pesticide satisfies the statutory
standard for registration. The standard requires, among other things,
that the pesticide will not cause ``unreasonable adverse effects on the
environment'' [FIFRA section 3(c)(5)]. The term ``unreasonable adverse
effects on the environment'' means ``any unreasonable risk to humans or
the environment, taking into account the economic, social, and
environmental costs and benefits of the use of any pesticide'' [FIFRA
section 2(bb)]. This standard requires a finding that the benefits of
each use of the pesticide outweigh the risks of such use, when the
pesticide is used in compliance with the terms and conditions of
registration and in accordance with commonly recognized practices.
The burden of proving that a pesticide satisfies the statutory
standard is on the proponents of registration and continues as long as
the registration remains in effect. Under FIFRA section 6, the
Administrator may cancel the registration of a pesticide or require
modification of the terms and conditions of a registration if the
Administrator determines that the pesticide product causes unreasonable
adverse effects to man or the environment. EPA created the Special
Review process to facilitate the identification of pesticide uses that
may not satisfy the statutory standard for registration and to provide
a public procedure to gather and evaluate information about the risks
and benefits of these uses.
A Special Review may be initiated if a pesticide meets or exceeds
the risk criteria set out in the regulations at 40 CFR part 154. When
EPA believes that a pesticide has met such risk criteria, a notice is
published in the Federal Register which announces the initiation of the
Special Review. After a PD 1 is issued, registrants and other
interested persons are invited to review the data upon which the review
is based and to submit data and information to rebut EPA's conclusions
by showing that EPA's initial determination was in error, or by showing
that use of the pesticide is not likely to result in unreasonable
adverse effects on human health or the environment. In addition to
submitting rebuttal evidence, commenters may submit relevant
information to support EPA's initial conclusions or to aid in the
determination of whether the economic, social and environmental
benefits of the use of the pesticide outweigh the risks. After
reviewing the comments received and other relevant materials obtained
during the Special Review process, EPA makes a proposed decision on the
future status of registrations of the pesticide.
The Special Review process may be concluded in various ways
depending upon the outcome of EPA's risk/benefit assessment. If EPA
concludes that all of its risk concerns have been adequately
[[Page 8188]]
rebutted, the pesticide registration will be maintained unchanged. If,
however, all risk concerns are not rebutted, then EPA will proceed to
assess risks and benefits. EPA considers possible changes to the terms
and conditions of registration that can reduce risks to a level that
satisfies the risk criteria used to initiate Special Review. If risks
can be reduced to the level, then the Agency considers whether the
benefits outweigh those risks. Based upon this analysis, it may require
that such changes be made in the terms and conditions of the
registration. Alternatively, EPA may determine that no changes in the
terms and conditions of a registration will adequately assure that use
of the pesticide will not cause any unreasonable adverse effects. If
EPA makes such a determination, it may seek cancellation, suspension,
or change in classification of the pesticide's registration. This
determination would be set forth in a Notice of Final Determination
issued in accordance with 40 CFR 154.33.
When the Administrator proposes to cancel, deny, or change the
classification of the registration of a pesticide product which is the
subject of a Special Review, regulations at 40 CFR 154.31(b) require
that the Agency submit notices of preliminary determination to the
Secretary of Agriculture and the Scientific Advisory Panel for review
and comment. In the case of the proposed decision for cyanazine, the
Agency does not deem this necessary because the cancellation of all
cyanazine products is a voluntary action on behalf of the registrants.
Issuance of this Notice means that the Agency has assessed the
potential adverse effects of cyanazine and has preliminarily determined
that continued, but limited, use of the pesticide under the agreed-upon
terms and conditions of cyanazine registration with DuPont and Griffin
will not present unreasonable adverse effects when considering: (1)
Risks and benefits of restricted, continued use of cyanazine through
the phaseout period and (2) the ultimate cancellation of all cyanazine
registrations. The Agency is proposing to terminate the Special Review
of cyanazine based on the fact that use will be restricted during the
phaseout period and no cyanazine use will be allowed after December 31,
2002, and, therefore, continuation of the Special Review is no longer
necessary. Included as part of the terms and conditions of cyanazine
registration are cyanazine registrants' waivers of rights to challenge
the Agency's final action on the cyanazine Special Review or the terms
and conditions of registration, including label amendments, required by
agreements in any court or administrative forum. The complete terms and
conditions that amend cyanazine registration are provided in Unit X. of
this Notice.
II. Summary of Toxicological Concerns
A. Carcinogenicity
The initiation of the Special Review of cyanazine in 1994 was based
on evidence that cyanazine may cause cancer in persons exposed to the
chemical through their diet (food and drinking water) and through
exposure while handling the chemical (mixer/loaders and applicators).
This risk concern is based on a statistically-significant incidence of
malignant mammary gland tumors in female Sprague-Dawley rats that were
exposed to cyanazine through their diet for 2 years. In addition to the
mammary gland tumors observed in these rats, the weight-of-the-evidence
for the carcinogenic potential of cyanazine includes the evidence that
cyanazine is structurally related to the other chloro-s-triazines which
also induce mammary gland cancer in female Sprague-Dawley rats.
Although cyanazine is structurally related to the other chloro-s-
triazines, cyanazine differs in that it contains a cyano (nitrile)
functional group that is highly reactive.
In March 1991, the OPP Carcinogenicity Peer Review Committee
evaluated the weight-of-the-evidence for cyanazine, with particular
emphasis on its carcinogenic potential. The Peer Review Committee
concluded that cyanazine should be classified as a Group C, possible
human carcinogen, and recommended quantification of human risk using a
linearized multi-stage model to extrapolate from effects seen at high
doses in laboratory studies to predict tumor response at low doses.
Using this model, the cancer potency equivalent (Q1*) for
cyanazine is 1.0 x 100 (mg/kg/day)-1 based on the development
of mammary gland adenocarcinomas and carcinosarcomas in female rats.
This represents the 95 percent upper confidence limit of tumor
induction likely to occur from a unit dose. The cancer classification
of cyanazine has not been presented to the FIFRA Scientific Advisory
Panel (SAP) for review.
A more detailed discussion about the evidence that cyanazine may
cause cancer can be found in the PD 1.
B. Comments Regarding the Carcinogenicity of Cyanazine and the Agency's
Response
Comment: DuPont Agricultural Products and Griffin Corporation responded
that the Agency does not have sufficient toxicological evidence to
support its position that cyanazine may pose a cancer risk to humans.
Both state that the Sprague-Dawley rat model is inappropriate and that
evidence supports their assertion that cyanazine tumorigenicity is
associated with a hormonally-mediated threshold effect.
Agency Response: In the PD 1 for atrazine, simazine, and cyanazine, the
Agency considered all information available at that time to evaluate
the carcinogenic potential of the triazines, including the
appropriateness of the Sprague-Dawley rat model, the method of
quantifying the carcinogenic risk and DuPont's assertion that cyanazine
tumorigenicity occurs through a hormonal mechanism. In response to the
PD 1, the Agency received additional information with comments
submitted for atrazine and simazine that will be reviewed and evaluated
in the continuing Special Review of those chemicals. The Agency
received no new information, however, to dispute the carcinogenicity
classification for cyanazine. Currently, it is the Agency's policy to
regulate carcinogens based on risk assessment procedures that utilize
the Q1* approach in the absence of data to support the
hypothesis of hormonally-mediated threshold responses. On several
occasions, DuPont has indicated that they have undertaken research that
will attempt to validate a hormonally-mediated mechanism of
carcinogenicity; however, the Agency received no information from
DuPont that attempts to prove such a mechanism exists.
Comment: DuPont does not believe that a link between breast cancer and
exposure to cyanazine exists and has stated that reviews of several
epidemiology studies on estrogen replacement therapy find no such link.
Agency Response: When the Agency initiated the Special Review for the
triazines, it had not concluded that cyanazine was directly related to
an incidence of human breast cancer. Upon review of published
literature, the Agency indicated that such tumor development in humans
seemed possible and that during the course of the Special Review,
further research into epidemiological studies would hopefully provide
information to make rational decisions about such cause and effect
relationships. The Agency is not in a position at this point to draw
any
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definitive conclusions about human breast cancer and cyanazine;
however, the Agency will continue to consider information throughout
the Special Review of the other triazines that may help clarify whether
an association exists. Information in published literature support the
possibility that some link between breast cancer and the triazine
herbicides is possible.
Comment: The National Coalition Against the Misuse of Pesticides
(NCAMP) provided comments about the triazines in general without
reference to cyanazine specifically. NCAMP supports the Agency's
Special Review of the triazines but unequivocally states that the
Agency must cancel the triazines due to unreasonable cancer risks.
Agency Response: The terms and conditions of DuPont and Griffin
cyanazine registrations now provide for voluntary cancellation of all
cyanazine registrations in 1999 and will eventually result in a total
phaseout of the use of cyanazine in the U.S. During the period of the
phaseout, the Agency estimates that the risks will be decreasing
because of the reductions in allowable maximum application rates and
the requirement that applicators must work in closed cabs. Taking the
cyanazine phaseout and voluntary cancellation into consideration, the
Agency has evaluated the risks and benefits of cyanazine and determined
that the terms and conditions of the phaseout and voluntary
cancellations, as submitted by the manufacturers and approved by EPA,
will ultimately eliminate any unreasonable adverse effects associated
with the use of cyanazine. Accordingly, the Agency is proposing to
terminate the Special Review. As with all Special Reviews, cancellation
of uses is an available option but is only imposed when other less
severe risk reduction measures are not adequate to eliminate
unreasonable adverse effects.
Comment: NCAMP commented that evidence supports the classification of
all of the triazines as Group B carcinogens.
Agency Response: The Agency has taken its decision about the cancer
classification of atrazine and simazine to the SAP on a number of
occasions. The SAP agreed with the Agency's cancer classification of
atrazine and simazine. Current weight-of-the-evidence for cyanazine
supports its classification as a Group C carcinogen. Further, NCAMP did
not provide any additional data or evidence to support their assertion.
Accordingly, the Agency has concluded that cyanazine is a class C
carcinogen. The Agency has not presented the cancer classification of
cyanazine to the SAP, and in light of the cyanazine phaseout and the
ultimate cancellation of this chemical, does not believe that it is
necessary to do so.
Comment: In general, Griffin commented that the Agency failed to
provide adequate information to allow others to fully evaluate its risk
assessments.
Agency Response: As required by the regulations governing Special
Review procedures, the Agency has provided a record of all background
documents used in its assessments through the public docket. The public
docket contains all supporting documentation that describes all of the
assumptions and values used by the Agency to conduct the risk
assessments. The Agency has made available the same level of
information for the cyanazine Special Review as it has for other
Special Reviews, and this information should be adequate to evaluate
the assessments.
III. Summary of Exposure and Related Human Health Risks
In the PD 1, the Agency provided upper bound estimates of
carcinogenic risks from dietary exposure from both food and drinking
water and occupational exposure to handlers (mixer/loader/applicators)
of cyanazine.
A. Dietary Exposure and Associated Risks
Dietary exposure to cyanazine can occur through the direct
consumption of cyanazine residues in treated food as well as from
commodities that contain secondary residues from animals that were fed
cyanazine-treated crops. In the PD 1, the Agency considered all
residues (per its equivalency policy), including parent cyanazine and
both chloro and hydroxy metabolites, to be of toxicological concern.
Anticipated residues were calculated using data from field trials,
processing studies, and metabolism studies.
The total upper bound dietary risk estimate from exposure to
cyanazine residues in food, as reported in the PD 1, is 2.9 x 10-
5. This estimate did contain a risk contribution from wheat and
sorghum, uses which have been voluntarily cancelled and thus removed
from cyanazine labels. Removing the risk contribution for wheat and
sorghum from the total decreases the total upper bound risk to 2.7 x
10-5. The Agency has not received any data that justifies the
revision of any of the assumptions used in its dietary risk assessment
other than the information with respect to the voluntary cancellation
of the wheat and sorghum uses. For a detailed discussion of those
assumptions, the reader is referred to the PD 1. Table 1 below provides
the dietary risk estimates as discussed in the PD 1.
Table 1.--Dietary Cancer Risk Estimates for Cyanazine
----------------------------------------------------------------------------------------------------------------
Anticipated Percent Crop Exposure (mg/kg/ Upper Bound Cancer
Commodity Residue (ppm) Treated day) Risk Estimates
----------------------------------------------------------------------------------------------------------------
Corn 0.12 20 1.2 x 10-5 1.2 x 10-5
Cottonseed 0.09 5 9.3 x 10-8 9.3 x 10-8
Milk 0.00028 (milk) -- 1.2 x 10-6 1.2 x 10-6
0.000034 (non-fat
solids)
Poultry and eggs 0.00232 -- 3.1 x 10-6 3.1 x 10-6
0.004322
Red meat 0.00345 -- 1.0 x 10-5 1.0 x 10-5
0.01031
Sorghum 0.10 5 1.2 x 10-7 1.2 x 10-7
Wheat 0.16 1 2.3 x 10-6 2.3 x 10-6
Total 2.9 x 10-5
Total excluding wheat and 2.7 x 10-5
sorghum
----------------------------------------------------------------------------------------------------------------
1Range of values were used for meat, meat byproducts, fat,
liver, and kidney.
2Range of values were used for meat, meat byproducts, fat,
liver, kidney and eggs.
[[Page 8190]]
B. Comments Regarding Cyanazine Dietary Risk Estimates and the Agency's
Response
Comment: Griffin contends that Anticipated Residue (AR) values used by
EPA were not identified and interpolation of EPA's calculations reveals
that values used are exaggerated and inappropriate for determining
actual dietary risks. Griffin further objects to the Agency's use of
translated data from cattle to estimate anticipated residues in other
animal commodities. DuPont disagreed with the extrapolation from
metabolism studies to estimate residues in meat, milk, and eggs and the
assumption that 100 percent of the livestock feed from corn, cotton,
wheat, and sorghum has been treated with cyanazine.
Agency Response: The AR values used in the Agency's risk assessment are
listed in Table 1 above and were identified in the PD 1 as well as in
the supporting documentation that was in the public docket at the time
of publication of the PD 1. In completing the dietary risk assessment
for cyanazine, the Agency utilized its standard approach to estimate AR
values and then used those values in determining dietary exposure
estimates and carcinogenic risk through its Dietary Risk Evaluation
System (DRES). Documentation supporting the estimation of ARs and
dietary exposure values is contained in the references used for the
triazine PD 1 and can be found in the triazine public docket. To
determine the cyanazine AR values for risk assessment purposes for crop
commodities, the Agency averaged the actual residues detected in field
trials; for nondetectable residues, the Agency assumed the residue
level equalled one-half of the analytical method's limit of detection.
This approach precludes the possibility of overestimating or
underestimating risks that could otherwise be based on residue values
at high or low detections. To estimate the ARs for animal commodities,
the Agency used animal dietary burden data which take into
consideration anticipated residues on feed crops as well as percent
crop treated data and animal metabolism studies. Since the consumption
of feed by animals has already been adjusted to account for the percent
of the crop that has been treated with cyanazine, use of the 100
percent assumption is appropriate.
The Agency routinely translates data between commodities with
sufficient similarities, such as translating apple data to pears.
Translation is performed when data are either not available or are
insufficient. In the case of cyanazine, crop data do exist. Data for
cattle and other ruminants can be translated only to other animals such
as goats, sheep, hogs or horses, but not to poultry. Ruminant data
exist for cyanazine and were used to estimate risks in the PD 1.
However, at the time the PD 1 was published, cyanazine poultry
metabolism data were not available. Therefore, atrazine poultry
metabolism data were translated to cyanazine. Since atrazine and
cyanazine were grouped for Special Review purposes due to their
structural and metabolic similarities, the Agency considered it to be
appropriate to bridge this data gap by translation. Griffin did not
provide an alternative risk assessment for the Agency to review or any
additional data for review and consideration in refining risk
estimates.
Comment: Griffin stated that the Agency's use of information from the
1977 - 1978 National Food Consumption Survey to estimate consumption
values is inappropriate because food consumption patterns have changed
dramatically over the past 17 years; therefore, ingestion rates used in
the dietary risk assessment are invalid. Griffin also stated that the
source of the percent crop treated data was not provided.
Agency Response: Although Griffin did not agree with the Agency's use
of the 1977 - 1978 information to predict ingestion rates, it provided
no data that the Agency could use to revise the consumption values. The
Agency acknowledges that the 1977 - 1978 National Food Consumption
Survey may not reflect the most current consumption profile of
individuals in the United States. The continuing surveys of food intake
by individuals were performed in 1989 through 1991; the Agency is
working to translate these data into a form useful for the Agency's
Dietary Risk Evaluation System. However, until these data are in a
useable form, the Agency will continue to use the 1977 - 1978 data.
The Agency revised the percent crop treated data for cyanazine in
1994 using the most current United States Department of Agriculture
(USDA) and other proprietary usage estimates that were available at
that time. The data reflect annual fluctuations in use patterns as well
as variability as a consequence of using data from various information
sources. Griffin did not supply any percent crop treated data for the
Agency to evaluate.
Comment: Griffin asserts that EPA calculations incorrectly assume that
all secondary sources of ingested cyanazine are contaminated with 100
percent of the AR level.
Agency Response: The Agency does use 100 percent of the AR level in its
calculations to estimate dietary risk; however, as discussed above, the
AR value has taken factors into consideration to adjust for the fact
that 100 percent of a crop may not be treated with the chemical.
Therefore, further percent crop treated adjustments are not necessary
and would tend to underestimate potential risks.
Comment: Griffin purports that EPA provided no specific information
about the exposure frequency and exposure duration values used in its
calculations; i.e., EPA assumes that an individual consumes a maximum
amount of a particular food all in the same day, every day, for an
entire lifetime and does not account for differences in exposure
duration for people living in urban areas, rural areas and farms.
Agency Response: The Agency acknowledges that there are differences in
food consumption habits across the U.S. To estimate chronic dietary
risk, the Agency considered information it has on the general U.S.
population as well as 22 population subgroups. The Agency's Dietary
Risk Evaluation System utilizes information that was obtained from the
1977 - 1978 food consumption survey discussed above. This survey was
designed to statistically encompass all income levels and all
population areas of the U.S., including participants from both rural
and urban areas. Average dietary consumption of an individual over a 3-
day period is determined. The consumption value is then matched to the
self-reported body weight of the individual. All data for both
consumers and non-consumers of a particular commodity are then combined
or averaged to determine dietary exposure. Currently, this survey
provides the best estimate of food consumption patterns in the U.S.,
assuming average consumption over a 70-year lifetime.
Comment: Griffin contends that EPA provided no information indicating
the values used for body weight assumptions.
Agency Response: Details about the assumptions used in the DRES
calculations were provided in the public docket. To calculate dietary
risk estimates for food and drinking water consumption, the Agency has
used information that was obtained in the 1977 - 1978 food consumption
survey. This survey matched individual consumption with individual
reported body weights of the respondents and the information is then
used by the Dietary Risk Evaluation System to estimate risk. Therefore,
the Agency has used the self-reported body weights to calculate both
the dietary and drinking water risk estimates. The self-reported body
[[Page 8191]]
weights average out to approximately 58 kg.
Comment: DuPont states that, because the use of cyanazine on sorghum
and wheat was voluntarily canceled, risks from these sources should be
removed from the risk assessment calculations.
Agency Response: The Agency accepted DuPont's request to voluntarily
cancel cyanazine use on wheat and sorghum. The Agency has removed the
risk contribution from use on wheat and sorghum from the dietary risk
assessment. The upper bound dietary risk estimate without the
contribution from wheat and sorghum is 2.7 x 10-5 which is still
considered to be unacceptable.
Comment: DuPont commented that EPA has presented upper bound risk
estimates only and ignored the most likely estimates which would be
orders of magnitude lower.
Agency Response: It is standard policy for the Agency to provide upper
bound carcinogenic risk estimates. The use of less than upper bound
risk estimates may not adequately account for risks to the most
sensitive populations such as infants, children, or the elderly. The
Agency acknowledges that the true risk estimates may be as low as zero
for some people in some risk scenarios; i.e. where no exposure is
present.
Comment: DuPont stated that EPA should not make the assumption that
chloro and hydroxy metabolites of cyanazine are as toxic as the parent
chemical.
Agency Response: In the absence of appropriate toxicological
information, it is the Agency's policy to use a default assumption that
metabolites are no more or no less toxic than the parent compound. The
Agency is not aware of any information that indicates that cyanazine
metabolites are less toxic than cyanazine itself. The Agency has
completed its review of the hydroxyatrazine study and is currently
determining the study's impact on atrazine and simazine anticipated
residue calculations. The Agency has decided that translation of the
results of this study to simazine is appropriate. However, because the
structure of cyanazine contains the cyano functional group and the
other two triazines in Special Review do not, the Agency has decided
that it would not be appropriate to translate results of the
hydroxyatrazine study to cyanazine.
C. Drinking Water Exposure and Associated Risks
Ground and surface water sources provide drinking water for human
consumption. While the Agency does not yet have an enforceable
regulatory standard or Maximum Contaminant Level (MCL) for cyanazine
contamination of drinking water, a lifetime Health Advisory Level (HAL)
has been established at 1.0 g/L. Information from a number of
ground and surface water monitoring studies has indicated that
cyanazine detections are frequently found, especially in surface
waters.
To prepare the PD 1, the Agency considered information from a
number of surface water monitoring studies that indicated the presence
of cyanazine in areas of the Midwest where it is frequently used. The
information from these studies indicates that cyanazine is detected in
many streams and rivers for several months post-application at
concentrations of at least several g/L due to runoff. However,
the percentage of detections is lower during early spring (pre-
application) and during fall and winter, many months after application.
Concentrations are usually less than 1.0 g/L. There are
reports of cyanazine detections in some lakes and reservoirs that
remain constant at several g/L almost year round. The ground
and surface water monitoring studies that provide evidence of cyanazine
contamination of water supplies are discussed in the PD 1.
The Agency based its drinking water risk concerns on the cyanazine
detections discussed above and calculated high end (90th percentile) as
well as risk estimates for mean consumption of cyanazine-contaminated
drinking water derived from both ground and surface water sources. In
the PD 1, the Agency's estimates from exposure to a mean concentration
of cyanazine in ground and surface water are 2.3 x 10-6 and 9.7 x
10-6, respectively. The upper bound risk estimates from a 90th
percentile exposure in ground and surface water are 4.0 x 10-6 and
6.6 x 10-5, respectively. These risk estimates may underestimate
the actual risk because they are based on exposure to cyanazine parent
compound only and do not include the potential contribution to risk
from cyanazine degradates. The Agency is also concerned about exposure
to cyanazine degradates that are assumed to be no more or less toxic
than the parent compound. It is important to note that the cyanazine
drinking water risk estimates are representative values for individuals
residing in the corn belt region where the chemical is used and do not
apply to the entire U.S. population, particularly areas where the
chemical is not used. Details about the Agency's drinking water
assessments for ground and surface water may be found in the PD 1.
Since the publication of the PD 1, the Agency has not received any
information that would significantly alter the cyanazine risk
estimates. Table 2 below shows the drinking water risk estimates as
provided in the PD 1.
Table 2.--Excess Individual Lifetime Cancer Risk Estimates from
Consumption of Cyanazine-Contaminated Surface and Ground Water
------------------------------------------------------------------------
Mean Exposure 90th Percentile
------------------------------------------------------------------------
Cyanazine - surface water 9.7 x 10-6 6.6 x 10-5
Cyanazine - ground water 2.3 x 10-6 4.0 x 10-6
------------------------------------------------------------------------
D. Comments Regarding Cyanazine Drinking Water Risk Estimates and the
Agency's Response
Comment: DuPont and Griffin contend that data from ground water
monitoring programs conclusively demonstrate that cyanazine ground
water detections are either nonexistent or extremely low. Neither EPA's
modeling nor actual ground water survey data support any regulatory
action to alter cyanazine registration status. DuPont and Griffin
specifically noted that studies cited in the PD 1 do not support the
claim that ground water contamination with cyanazine is a concern.
Agency Response: The Agency continues to believe that cyanazine
contamination of ground water supplies poses concerns. Griffin was
correct in stating that cyanazine was not detected in EPA's National
Survey of Pesticides in Drinking Water Wells. However, the detection
limit in the survey was 2.4 g/L whereas the Agency's HAL for
cyanazine is 1.0 g/L. It is quite possible that there were
undetected residues of cyanazine at or greater than the HAL but less
than the detection limit. The fact that cyanazine was detected in few
[[Page 8192]]
wells in the Monsanto National Alachlor Well Water Survey is reasonable
because the survey focused on the alachlor use area. The Agency does
not believe that the use of cyanazine geographically coincides closely
enough with the use of alachlor to rely heavily on the results of this
study to be representative of the contamination potential of cyanazine.
For example, in Illinois, only a small percentage of the total corn
acreage is treated with both alachlor and cyanazine. Most alachlor
applications are accompanied by treatments with atrazine, dicamba, or
glyphosate. Therefore, it would be less likely to detect cyanazine in
alachlor use areas. Also, no degradates were analyzed for in the
survey. Griffin further stated that no cyanazine was detected in ground
water during retrospective studies conducted by Shell. Although the
wells were located near fields in which corn had been grown in the last
5 years, in areas where 60 - 69 percent of the wells were tested,
cyanazine was not used or usage could not be confirmed in the
associated corn field. Therefore, these studies do not represent the
most accurate impact of cyanazine use on ground water quality.
Cyanazine was detected in 155 of 7,468 wells as noted in EPA's
Pesticides in Ground Water Database. The cyanazine detections in the
wells of 14 states probably resulted from nonpoint source mechanisms.
The Agency acknowledges that the parent cyanazine compound may not
be very persistent under most field conditions; however, total chloro-
degradate residues of cyanazine are potentially very persistent
depending on environmental conditions such as those that may be found
in ground water reservoirs. The Agency also acknowledges that less
information is available about the contamination of ground water with
cyanazine than with atrazine simply because cyanazine has not been as
extensively researched as atrazine. However, the information that the
Agency does have about the fate characteristics of cyanazine, the
monitoring data, and the large amounts of cyanazine that are used
continues to support the Agency's concern for ground water
contamination.
Comment: DuPont stated that the Agency has no information indicating
that cyanazine metabolites will reach ground water in concentrations of
toxicological concern.
Agency Response: The Agency has limited data on the detection of
cyanazine degradates in ground water; however, cyanazine is
structurally similar to atrazine and simazine and has similar
environmental fate characteristics with some common degradates. Because
of the similarity in fate characteristics, the Agency believes that it
is reasonable to assume that cyanazine degradates may reach ground
water supplies. Both atrazine and cyanazine degrade to deisopropyl
atrazine, a chlorodegradate that the Agency assumes to be no more or
less toxic than the parent compound.
Comment: Griffin commented that EPA's use of CHEMRANK and LEACH models
overestimates cyanazine's leaching potential.
Agency Response: The Agency believes that the models used are helpful
in judging whether significant differences exist in the leaching
potential between different pesticides but are not truly predictive of
the amounts of pesticides that will leach to ground water at a
particular site. In addition, the screening models used do not take
degradates into account; one particular cyanazine degradate,
deisopropyl atrazine, is extremely mobile and has been widely found in
ground water. So, the models may in fact underestimate risk.
Comment: The South Dakota and Minnesota Departments of Agriculture and
the Illinois Environmental Protection Agency submitted surface water
monitoring data in response to the PD 1 that included information for
cyanazine.
Agency Response: The Agency has considered the data submitted by each
of these commenters. The South Dakota and Minnesota data were
consistent with United States Geological Survey (USGS) 1989 and 1990
reconnaissance studies of the Midwestern corn belt that showed levels
of cyanazine in the surface waters of those states generally to be
substantially lower than in several other states such as Illinois, Iowa
and Ohio. Although the available data are not sufficient to conclude
with certainty that cyanazine is not a potential problem in either
state, the Agency's primary concerns were and remain at this time with
some of the other corn belt states. For example, arithmetic average
annual cyanazine concentrations for samples collected from West Lake,
IA, exceeded the HAL in 1992 and 1993, and for samples collected from
Rathbun Reservoir, IA, exceeded the HAL in 1992 and 1994. Although
these averages are arithmetic and are only of detects, the Agency
believes in this case that the arithmetic averages are relatively close
to time-weighted mean concentrations because of the regularity of the
sampling dates. Such regularity would not be observed if there were a
significant number of non-detects or if the sampling schedule was
skewed. Additionally, the Agency received raw data from the
Environmental Working Group in which 29 surface water supplies were
monitored for cyanazine biweekly from March, April or May through
August 1995. Using these data, the Agency calculated time-weighted mean
concentrations. Six of the 29 systems sampled had cyanazine estimated
time-weighted mean concentrations greater than the HAL of 1.0
g/L (Bowling Green, OH - 1.4 g/L; Columbus, OH - 1.04
g/L; Danville, IL - 2.47 g/L; Decatur, IL - 1.88
g/L; Johnson County, KS - 1.01 g/L; and Springfield,
IL - 3.07 g/L) (Ref 6).
In response to the PD 1, the Illinois Environmental Protection
Agency submitted data to update their network of 30 raw surface water
sampling sites from the Moyer and Cross report that covered 1985 - 1988
to include 1989 - 1993. Also provided were data on cyanazine
concentrations in finished water samples collected quarterly from
September 1992, to June 1994, from numerous surface water source
supplies throughout the state. Although the data updating the 30 raw
water sampling stations is in summary form with only mean
concentrations provided for the entire sampling period (1985 - 1993)
given for each site, the reported cyanazine average concentrations
equaled or exceeded the HAL at 7 of the 30 sites and equaled or
exceeded 3 g/L at 2 of those sites, even with the damping
effect associated with long-term multiple year averaging. Although the
arithmetic averages may be somewhat greater than time-weighted mean
concentrations, the Agency believes that they are probably not that
much greater due to the general collection of samples pre-application
and during the fall as well as a small number post-application. The
data further support the Agency's position that cyanazine detections in
the surface waters of Illinois remain of concern.
Comment: Griffin and DuPont commented that detections of cyanazine in
surface water fluctuate seasonally with detections peaking in spring
and summer but returning to background levels that do not present
health concerns for the majority of the year. DuPont believes that
studies on effectiveness of best management practices (BMP) provide
evidence that DuPont's BMP efforts have helped reduce surface water
levels.
Agency Response: The Agency agrees that cyanazine detections tend to be
seasonal; however, the detections that are reported remain as a concern
to the Agency. Monitoring data post 1990 from West Lake and Rathbun
Reservoir in
[[Page 8193]]
Iowa, as well as data provided to the Agency by the Environmental
Working Group and the Illinois Environmental Protection Agency, support
the Agency's concern that average annual cyanazine concentrations in
some surface source drinking water supplies continue to exceed the HAL
of 1 g/L. Data from studies conducted by Baker in Ohio and the
USGS in the Midwestern corn belt show that maximum cyanazine
concentrations exceed the HAL and that such concentrations may last
several weeks post-application. The Agency agrees with DuPont's
statement that concentrations of cyanazine exceeding 10 g/L
are more likely to occur in small streams rather than larger streams
and rivers where the concentration is likely to be diluted. DuPont's
assertion that small streams do not generally supply drinking water is
true. However, cyanazine concentrations often remain elevated for
longer periods of time in larger streams and rivers due to cyanazine
loadings that occur at different times within the watershed upstream
from the sampling location. Also, cyanazine concentrations appear to
remain elevated longer in lakes and reservoirs such as West Lake and
Rathbun Reservoir due to lower microbiological activities coupled with
long hydrological residence times. In the USGS reconnaissance survey of
129 surface water sites within the Midwestern corn belt, greater than
10 percent of the sites had post-application concentrations of
cyanazine greater than 10 g/L; in the study by Baker of eight
tributaries of Lake Erie over 4 years (32 site-years), 19 percent had
maximum concentrations exceeding 10 g/L.
The Agency does believe that the changes brought about by the
adoption of the BMPs has helped to decrease the triazine loading of
surface waters. The Agency believes that the reduction in use rates
called for during the phaseout of cyanazine will further help reduce
the loading to surface waters from agricultural runoff. However, the
decreases observed since the use of BMPs are small and recent data show
that cyanazine contamination of some surface water source drinking
supplies continues to be a concern.
Comment: DuPont disagrees with the Agency's use of a 20 percent
Relative Source Contribution (RSC) factor to calculate the HAL and
suggests that the Agency revisit this issue before assessing risk based
on the current number.
Agency Response: The RSC value is a factor that is used to establish
regulatory standards for levels of a contaminant in drinking water. The
RSC apportions the allowable doses of a contaminant that are derived
from food, water and air. In the case of cyanazine, the Agency has used
the default value of 20 percent due to lack of data to support any
other value. In other words, the Agency is allowing only 20 percent of
the total amount of cyanazine exposure to come from drinking water; the
remaining 80 percent can be contributed through other exposure routes
such as food and air. In 1994, DuPont requested that the Agency revise
the RSC value and modify the cyanazine HAL accordingly. The Agency
responded to DuPont's request, concluding that the 20 percent default
value for the RSC was appropriate at this time due to uncertainties
associated with the contribution of total triazines and their
degradates to the total exposure. The Agency has received no additional
information that warrants making this change and, therefore, continues
to believe that the default value is appropriate. In the PD 1, the
Agency's calculations to determine drinking water risk estimates do not
use the RSC value or the HAL for cyanazine since actual intake survey
data were used to estimate consumption of drinking water and monitoring
data were used to estimate exposure to cyanazine. Therefore, changing
the RSC value would have no effect on the Agency's drinking water risk
estimates.
Comment: DuPont disagrees that inclusion of cyanazine metabolites may
increase exposure to cyanazine by 10 percent. DuPont submitted data on
metabolites in several reservoirs.
Agency Response: In the PD 1, the Agency's statement that degradates
could increase exposure by 10 percent referred to total triazine
degradates in general and did not refer specifically to cyanazine. The
study on metabolites in reservoirs, to which DuPont refers, had very
high detection limits for major cyanazine degradates; therefore, it is
reasonable to conclude that cyanazine degradates were detected in a
relatively low percentage of samples. However, in some of the samples
where degradates were detected, they were at concentrations comparable
to those of parent cyanazine.
Comment: DuPont agrees that there are numerous sites where a single
measurement or even several measurements may exceed the HAL for
cyanazine, yet the annual mean may not exceed the HAL. DuPont states
that it is inappropriate to use chronic exposure standards in dealing
with exposure from surface waters which are highly variable.
Agency Response: The Agency agrees that the concentration of individual
surface water samples taken at a given point in time should not be
compared to long-term regulatory standards and has only compared
arithmetic and time-weighted annual mean concentrations to the HAL for
cyanazine. The Agency has compared some maximum and individual
cyanazine concentrations to short-term HALs and to 4 times the HAL. The
rationale for comparing maximum or other individual concentrations to 4
times the guidance value is that any single quarterly concentration
that is greater than 4 times the guidance value will automatically make
the annual average of four successive quarterly samples greater than
the guidance value. If this guidance value was actually a regulatory
standard, the system would be out of compliance with the Safe Drinking
Water Act.
Comment: EPA reports that a high percentage of samples from the
Chesapeake Bay have triazine detects. DuPont believes such detects
should be quantified when assessing risk.
Agency Response: The statement in the PD 1 about a percentage of
triazine detections in the Chesapeake Bay was intended to support the
fact that the triazines are widely distributed in surface waters. The
statement was not meant to be interpreted as any measure of risk but
rather the far ranging distribution of the triazines in the
environment. Also, the statement referred to atrazine only, not
cyanazine, and stated that a small percentage of detections were
greater than 3 g/L.
Comment: DuPont recommends that EPA reconsider appropriate action
levels for regulating drinking water contaminants that can occur at
varying levels over time. Using an identical exposure level over 70
years of exposure represents excessive conservatism in risk management.
Agency Response: Actual exposure data on the same watershed over many
years are not available so the Agency cannot conduct assessments as
recommended by DuPont. Results using modeling, a possible future
option, are currently not sufficiently reliable to use in absolute
comparisons to MCLs or MCLGs. In addition, for regulatory purposes, the
Safe Drinking Water Act requires the comparison of running annual
average concentrations based upon four successive quarterly samples to
be compared to the MCL. The Agency acknowledges that the use of water
from the same source containing the same contaminant level is
conservative since most of the U.S. population moves at some time
during their life and does not live in the same area drinking from the
same water source for a 70-year lifetime. However, it could be
considered as
[[Page 8194]]
either an over- estimation or under-estimation depending on the
contaminant levels in the other sources of drinking water.
Comment: DuPont disagrees with EPA's statement that the concentration
of cyanazine in a watershed is proportional to the watershed's size.
Agency Response: The Agency did not state that the concentration of
cyanazine in a watershed is directly proportional to the watershed
size. DuPont has misquoted the statement actually made in the PD 1. The
Agency stated that ``peak concentrations of triazines are generally
greater in surface waters draining small watersheds than in those
draining large watersheds. . . .'' The statement was intended to be
interpreted in the context of discussing watersheds which receive high
cyanazine applications. As discussed earlier, smaller streams tend to
have higher concentrations than do larger streams and rivers.
Comment: DuPont is not aware of any data showing that tile drainage
and/or ground water inflow contributes substantially to cyanazine
loading of surface waters.
Agency Response: Both Moyer and Cross (1990) and Squillace and Engberg
(1988) believe that tile drainage and/or ground water inflow sometimes
contribute significantly to triazine loadings of surface waters.
Because cyanazine has a shorter half-life in surface soil than does
atrazine, such contributions are probably substantially smaller for
cyanazine than for atrazine.
Comment: DuPont commented that EPA indicates that the cumulative
effects of various triazines are assumed to be additive. DuPont
disagreed stating that information in a study report they submitted in
response to the PD 1 entitled ``Assessment of the Reproductive and
Developmental Toxicity of Pesticide/Fertilizer Mixtures Based on
Confirmed Pesticide Contamination in California and Iowa Ground
Water,'' indicates no additive effects and that safety margins in the
HAL are more than adequate to protect human health and the environment.
Agency Response: Although it is unclear, the Agency assumes that DuPont
is referring to additive toxic effects of pesticides as it relates to
the Agency's combined risk assessment across several triazines and
exposure routes in the PD 1. The study to which DuPont is referring
assessed the reproductive and developmental toxicity, not
carcinogenicity, of pesticide/fertilizer mixtures based on ground water
contamination. The Agency continues to believe that additive effects of
exposure to multiple chemicals may increase risks and will continue to
evaluate and revise the combined risk assessment as appropriate though
the continuing triazine Special Review. Safety margins built into HALs
do not account for additive effects of multiple chemical exposures.
Comment: Griffin commented that the exposure values EPA used to
characterize daily intake of drinking water are not consistent among
the calculations to determine risk from exposure at the HAL, risk from
surface water exposure and risk from ground water exposure or with
accepted risk assessment methodology.
Agency Response: The Agency acknowledges that different body weight
assumptions were used in calculating the risk assessment performed for
exposure at the HAL (The Agency specified a 70 kg body weight and 2 L/
day water consumption value in the PD 1) than were used to calculate
risks from ground and surface water consumption. Calculating risk at
the HAL is a screening level assessment similar to using tolerance
level residues to estimate risk for dietary consumption. The Agency
acknowledges that there can be different default assumptions for water
consumption; however, the 2L value used to determine the HAL is a
traditionally accepted value. However, the Agency provided a refined
assessment for the PD 1 that used actual ground and surface water
monitoring data and self-reported body weights from the 1977 - 1978
food consumption survey. Use of actual data to estimate risks, as was
done in this case, provides a more realistic estimation than does using
default assumptions such as exposure at the HAL or an assumed value for
body weight.
Comment: Griffin stated that EPA has consistently used maximum or high-
end values in the drinking water evaluation. The basis for using time-
weighted averages is not clear. Actual exposure and risk is doubled
because: (1) EPA has not considered surface water treatments that may
reduce contamination, (2) it appears that EPA used a body weight of 50
kg in its calculations, and (3) EPA applied an exposure value
reflecting tap water only and not commercial beverages. EPA has used
maximum values in its drinking water assessment even though cyanazine
has actually been detected in few samples.
Agency Response: The Agency disagrees with Griffin's statement that
maximum or high-end values have been used to estimate exposure in
drinking water. The Agency has used time-weighted mean concentrations
to provide a better estimate of the exposure to triazine residues over
an extended period of time in order to reduce any over- or
underestimation effects that may result from the variability of
detection levels at specific sampling times. In estimating exposures in
surface waters, time-weighted mean concentrations are generally better
approximations of the actual time integrated mean concentration than
are arithmetic means whose values tend to be greater due to the general
increase in sampling frequency during periods when the highest triazine
concentrations are expected.
The Agency has not considered surface water treatment effects on
the exposure to cyanazine because it cannot be assumed that all
individuals are consuming drinking water that has actually been
treated. It cannot be assumed that every household is connected to a
public water system that provides adequate treatment to remove possible
triazine contamination. Since most water systems employ only primary
treatment methods (e.g., solids removal), cyanazine concentration in
raw and in finished water should generally be comparable. It is true
that the Agency did not include ``commercial water'' such as that added
during the manufacturing and processing of beverages. The survey from
which the Agency has taken the drinking water consumption value only
included tap water that is consumed directly or that is used in the
preparation of foods or beverages in the home.
Comment: DuPont submitted a number of studies in response to the PD 1
that provides information about the effects of BMPs on cyanazine
movement in the environment.
Agency Response: The Agency has not reviewed these studies to prepare
this Notice. As discussed earlier, the Agency does not believe that the
BMPs that have been put in place have totally addressed the Agency's
ground and surface water concerns because of the more recent monitoring
data that continue to show detections. These studies will be considered
in the continuing Special Review of atrazine and simazine to evaluate
the effects of BMPs on herbicide environmental contamination. Even
though some of the BMPs may have a positive impact on ground and
surface water contamination and potential ecological effects, the risk
concerns associated with occupational exposure and dietary exposure
from food consumption will remain unchanged.
Comment: The Environmental Working Group (EWG) submitted its report
``Tap Water Blues'' to the Agency in response
[[Page 8195]]
to the initiation of the triazine review. EWG also submitted a follow-
up report entitled ``Weed Killers by the Glass'' which indicates
cyanazine detections in drinking water samples taken directly from the
taps in people's homes or offices.
Agency Response: The Agency thinks that the data indicating cyanazine
detections in drinking water are significant and support the Agency's
risk concerns. As discussed earlier, some of the water systems that
were sampled by EWG had time-weighted mean concentrations higher than
the cyanazine HAL of 1.0 g/L. The Agency will fully evaluate
the information with respect to atrazine and simazine as part of the
continuing Special Review of the triazines.
Comment: EWG comments that EPA standards for triazines in food and
drinking water are not consistent and allow levels in drinking water
that are unsafe and would not be allowed in foods. EWG points out that
there is no enforceable standard for cyanazine and recommends
promulgation of a combined MCL for the triazines, including
metabolites. NCAMP also commented that the Agency's regulation of
contaminants in drinking water is less stringent than the regulation of
residues in food and that metabolites should be included in all
regulatory standards.
Agency Response: While the Agency does not have an MCL for combined
triazines, including metabolites at this time, it is considering
establishing such an enforceable standard. Because cyanazine is being
phased out over the next several years, it is unlikely that the Agency
will establish an MCL for cyanazine.
Comment: EWG recommends weekly monitoring of drinking water in
susceptible regions for all triazines and metabolites during high
runoff and vulnerable periods. EWG also recommended that exposure
estimates must include recent data from Missouri and other states
demonstrating that peak exposures and annual average concentrations for
many rural communities far exceed health standards.
Agency Response: The Safe Drinking Water Act establishes the
requirements for monitoring pollutants in drinking water. The Agency
will consider the most recent monitoring data available to estimate
triazine exposure in drinking water when the risk estimates are revised
for the preliminary determination of the triazine Special Review.
Comment: EWG commented that the Agency must concentrate its risk
assessment only on exposed populations. Unexposed populations deflate
risks faced by people with contaminated water.
Agency Response: The Agency acknowledges the value of this comment and,
providing that adequate information is available, will respond to this
issue in the PD 2/3 for atrazine and simazine.
E. Occupational Exposure and Associated Risks
For the PD 1, the Agency determined exposure estimates for
cyanazine use on corn, the predominant use site, for different
scenarios depending on whether the person exposed to cyanazine was
mixing, loading or applying cyanazine or performing a combination of
these tasks. Additionally, estimates were provided for growers and
commercial applicators and whether open or closed equipment is used.
Those estimates were based only on dermal exposure assuming a dermal
absorption value of 2 percent and a use rate of 3 pounds active
ingredient per acre (lb/ai/acre).
Just prior to initiating the triazine Special Review, DuPont
provided the Agency with its own occupational risk assessment that
estimated exposure to cyanazine by using information in the Pesticide
Handlers Exposure Database (PHED) for ground application (Ref. 7).
After reviewing DuPont's assessment, the Agency revised its own risk
assessment for ground application of cyanazine by using PHED
information to estimate worker exposure (Ref. 8). Aerial application
risks were not revised and remain as reported in the PD 1. The Agency
used a more recent version of PHED (version 1.1) than did DuPont
(version 1.01) that contains more data and therefore provides a greater
degree of confidence in the exposure estimates. Table 3 below provides
the Agency's revised occupational risk estimates as well as DuPont's
estimates for groundboom application of cyanazine.
Table 3--Exposure and Risk Estimates for Groundboom Applications of Cyanazine to Corn
--------------------------------------------------------------------------------------------------------------------------------------------------------
Daily Exposure mg/ Annual Exposure Estimated Upper Estimated Risk
kg/day mg/kg/year LADE mg/kg/day Bound Risk (EPA) (Dupont)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Grower
Mixer/Loader Open 0.0099 0.0109 1.5 x 10-5 1.5 x 10-5 1.71 x 10-6
Applicator Open 0.0044 0.0048 6.5 x 10-6 6.5 x 10-6 5.2 x 10-7
M/L/A Open 0.0143 0.0157 2.2 x 10-5 2.2 x 10-5 2.23 x 10-6
Mixer/Loader Closed 0.0020 0.0022 3.0 x 10-6 3.0 x 10-6 N/A
Applicator Closed 0.0016 0.0018 2.4 x 10-6 2.4 x 10-6 N/A
M/L/A Closed 0.0036 0.0040 5.4 x 10-6 5.4 x 10-6 N/A
Commercial
Mixer/Loader Open 0.0729 0.0874 1.2 x 10-4 1.2 x 10-4 5.28 x 10-5
Applicator Open 0.0321 0.0385 5.3 x 10-5 5.3 x 10-5 4.64 x 10-6
M/L/A Open 0.1050 0.1259 1.7 x 10-4 1.7 x 10-4 5.75 x 10-5
Mixer/Loader Closed 0.0147 0.0177 2.4 x 10-5 2.4 x 10-5 N/A
Applicator Closed 0.0117 0.0139 1.9 x 10-5 1.9 x 10-5 N/A
M/L/A Closed 0.0264 0.0316 4.3 x 10-5 4.3 x 10-5 N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
Daily Exposure = lb ai/day X Unit exposure X % Dermal absorption/70
Annual Exposure = lb ai/year X Unit exposure X % Dermal absorption/
70
LADE = Annual exposure } 365 X 35/70
Risk = LADE X Q*
Dermal absorption = 2% (DuPont's estimates are based on 1% dermal
absorption)
Q* = 1
[[Page 8196]]
F. Comments Regarding Cyanazine Occupational Exposure Risk Estimates
and Agency's Response
Comment: Griffin asserts that: (1) EPA has used an application rate of
3 lb/ai/a, but states that 1.5 lb/ai/acre is commonly used for
cyanazine, and that using the higher rate is a violation of EPA's legal
obligation to base regulatory activities on actual data, (2) EPA used a
dermal absorption value of 2 percent to calculate risks, while studies
indicate the actual dermal absorption value to be .84 percent, and (3)
EPA's risk assessment is overestimated and meaningless because
application rates were doubled and the dermal absorption value was
exaggerated.
Agency Response: The Agency has estimated occupational exposure to
cyanazine based on an application rate of 3 pounds per acre when
applying cyanazine alone. The Agency noted in its risk assessment that
a rate of 1.5 pounds per acre is often used; however, this rate is
typically used when cyanazine is applied in combination with another
herbicide, often atrazine. While some cyanazine usage occurs at rates
greater than 3 lb/ai/acre (up to greater than 5.0 lb/ai/acre) the
majority of usage occurs at rates of 3 lb/ai/acre or less. The dermal
absorption rate used in the Agency's risk calculation is based on the
actual amount absorbed plus the amount remaining bound to the skin
after washing as shown in a dermal absorption study. Therefore, the 2
percent value used in the Agency's risk assessment represents the total
amount of cyanazine that could potentially be absorbed through the
skin. Assuming that the amount remaining bound to the skin after
washing will be absorbed over time is consistent with the Office of
Pesticide Programs' risk assessment practices.
Comment: DuPont commented that occupational exposure risks were in the
acceptable range and referenced their risk assessment submitted to the
Agency.
Agency Response: After reviewing DuPont's assessment, the Agency
revised its occupational risk assessment and then compared the two. In
using updated PHED information, the Agency's revised risk estimates
were lower than those estimates originally reported in the PD 1;
however, the risk estimates are not as low as those estimated in
DuPont's assessment. The assumptions that the Agency used in its risk
estimates vary from the assumptions used by DuPont. The Agency's unit
exposure estimates are based on a newer version of PHED and the Agency
has also used a different dermal absorption value than DuPont, as
discussed above. The Agency used information from PHED derived from
atrazine studies in which application parameters comparable to those
for cyanazine were used. DuPont's assessment for applicators is
unacceptable due to the lack of sufficient replicates used. Most of the
exposure estimates for applicators were based on data representing less
than the required minimum of 15 replicates per body part. Further, for
some of the exposure scenarios used by DuPont, the risks were higher
than negligible and of concern. The Agency has used updated use and
usage information to estimate the number of acres treated for exposure
estimations. Therefore, the Agency believes its revised estimates are
more accurate than those presented in the PD 1 and those calculated by
DuPont.
G. Combined Cancer Risks Across Multiple Exposure Pathways and
Chemicals
In the notice initiating the Special Review of the triazine
herbicides, the Agency provided examples of assessments of total risk
that was possible to individuals who may be exposed to more than one of
the triazines and from more than one exposure pathway. This was the
first time that the Agency looked at the additive risks associated with
a group of similar pesticide chemicals. In the combined risk
assessment, the Agency provided estimates of the total risk from
exposure to atrazine, simazine and cyanazine from dietary, drinking
water, occupational and residential exposure. In the PD 1, the Agency
acknowledged that various total risk estimates were possible depending
on the combination of chemicals to which one is exposed and the
combination of exposure routes. With the ultimate phaseout of the use
of cyanazine, this chemical will eventually cease to contribute to the
total combined triazine risk. However, during the phaseout, while
cyanazine continues to be used, the Agency will continue to evaluate
its contribution to the total risks of the triazine herbicides in
Special Review. Table 4 below shows the Agency's upper bound estimates
of total cancer risks across several exposure pathways and triazines.
Table 4.--Upper Bound Total Cancer Risks Across Several Exposure Pathways and Triazines
----------------------------------------------------------------------------------------------------------------
Exposure Pathway Atrazine Simazine Cyanazine1 Total
----------------------------------------------------------------------------------------------------------------
Dietary 4.4 x 10-5 1.1 x 10-5 2.7 x 10-5 8.2 x 10-5
Drinking Water2 4.2 x 10-6 6.2 x 10-7 9.7 x 10-6 1.5 x 10-5
Occupational3,4 1.1 x 10-3 N/A N/A 1.1 x 10-3
Residential5 1.1 x 10-4 N/A N/A 1.1 x 10-4
Total 1.3 x 10-3 1.2 x 10-5 3.7 x 10-5 1.3 x 10-3
----------------------------------------------------------------------------------------------------------------
1Risk contribution from use on wheat not included.
2Derived from surface water.
3Private grower application to corn using ground boom
equipment - mixer/loader/applicator.
4Application of a combination of atrazine and cyanazine.
5Lawn treatment by homeowner using hand cyclone spreader.
H. Comments Regarding Combined Risk Estimates and Agency's Response
Comment: Griffin commented that EPA has failed to recognize that a
critical factor to be addressed when combining risks is the compounding
of maximum values. For example, if 90th percentile values are used to
assess risk for each pathway to be combined, the total risk actually
represents an estimate closer to a 95-99th percentile range, an
overexaggeration that reduces the value of the risk estimate for
decision making.
Agency Response: The Agency acknowledges that a simple additive
approach was used in combining the risks for atrazine, simazine, and
cyanazine. This approach was deemed scientifically sound as the
estimates were based on the induction of the same tumor type in the
same animal strain, quite possibly via the same or similar mode or
mechanism of action. The combined risk estimate contains all of the
uncertainties of the numbers used in the individual calculations. If
all of the triazine risk numbers were roughly of
[[Page 8197]]
the same magnitude, then addition of many upper bound numbers could
eventually lead to an over-estimate of risk. However, adding upper
bounds in this case should not be considered to over-estimate the risk
since one chemical or one pathway ``drives'' the risk. In the case of
the triazines, the occupational risk from atrazine of 1.1 x 10-3
is driving the overall risk of 1.3 x 10-3.
Comment: EWG and NCAMP support the Agency's combined risk assessment
for the triazines. EWG requests that the Agency calculate the effect of
exposure to infants and children on their lifetime cancer risks, the
average exposure levels for infants and young children, the degree to
which it is disproportionately occurring in early life and the
significance of this exposure. NCAMP further urges the Agency to extend
that risk assessment concept to include all pesticides with similar
toxic endpoints.
Agency Response: The Agency agrees that it is important to consider the
differences between infants, children, and adults when estimating risks
and is working to develop scientifically-sound methodologies to account
for such differences in sensitivity and/or exposure and their impact on
the lifetime cancer risk estimates. Many factors such as the length of
exposure and variations in exposure levels need to be considered in the
risk assessment process. The triazines Special Review is the first case
study for estimating total risks from chemicals which are similar. The
Agency will likely apply the principles that are used in the combined
risk assessment in the triazine case study to estimate combined risks
from other pesticides that have concurrent exposure and/or common
mechanisms of toxicity in future risk assessments.
IV. Summary of Exposure and Related Ecological Risks
At the time the Agency initiated the Special Review of atrazine,
simazine, and cyanazine, it did not include ecological risk as a formal
trigger to initiate the review. The Agency did, however, express
concerns about the potential risks to aquatic organisms, terrestrial
plants and their ecosystems. The Agency based its concern on a number
of studies that indicate acute effects on various aquatic organisms and
terrestrial plants. These studies were discussed in detail in the PD 1
and the Agency requested any additional information about ecological
effects at the time the Notice was published. The Agency did not
receive any new information or new studies that either supported or
rebutted its concern about potential ecological risks from the use of
the triazines; therefore the Agency has not changed its position
regarding the ecological effects. Even though this Notice is proposing
the termination of the cyanazine Special Review, the Agency will
continue to look at adverse effects on ecological parameters in the
continuing Special Review of atrazine and simazine.
Comments Regarding Ecological Risks and Agency's Response
Comment: NCAMP supported the Agency's concerns about potential
ecological risks associated with the triazines and cited a number of
published studies about the toxic effects on aquatic and terrestrial
organisms.
Agency Response: NCAMP did not provide any information other than
citing several studies about the potential ecological risks of the
triazines. The Agency conducted a comprehensive literature search and
considered all published information in its assessment of triazine
ecological risks at the time the triazine PD 1 was issued. The studies
that supported the Agency's ecological concerns are discussed in detail
in the PD 1. In the PD 1, the Agency stated that exclusion of
ecological risks as a Special Review trigger at that time would not
preclude the Agency from including those risks in the review at a later
time, should additional information warrant it. The Agency will
continue to evaluate ecological concerns as the Special Review of
atrazine and simazine proceeds. If new information becomes available
that changes the Agency's position regarding the ecological risks of
atrazine and simazine, the Agency may include them in the Special
Review.
V. Summary of Qualitative Benefits and Impacts of Phaseout and
Voluntary Cancellation
Cyanazine is a broad spectrum herbicide which is registered for the
control of many annual grasses and broadleaf weeds in corn, cotton, and
sorghum. About 23 - 36 million pounds active ingredient of cyanazine
are applied each year in the U.S. Corn accounts for 95 percent of
cyanazine usage with between 18 and 21 percent of the field corn
acreage treated each year. Cotton accounts for about 3 percent of all
usage with between 12 and 20 percent of the cotton acreage treated
annually. Sorghum and sweetcorn account for less than 1 percent of all
cyanazine usage with between 1 and 3 percent of the sorghum acreage and
about 20 percent of sweet corn acreage treated annually.
Cyanazine provides the grower with flexibility of application
(preplant, preemergence, postemergence) and residual activity in
addition to burndown in no-till crop management. A second advantage,
compared to the widely used atrazine-based products, is that cyanazine
is less persistent following application, which results in shorter
residual activity. Thus, a significant advantage of cyanazine alone or
in mixtures with atrazine, compared to atrazine alone or atrazine in
combination with other herbicides, is the ability to plant any
triazine-sensitive rotational crop in the fall or the spring following
the application without the concern of carryover. This flexibility is
extremely important in regions where growing seasons are shorter, which
may result in herbicide applications being made later in the spring. A
third advantage is that cyanazine offers the grower a wide weed control
spectrum, especially against several problem grass species. Therefore,
in some cases a second grass herbicide may be unnecessary, or can be
used at a reduced application rate.
The Agency has evaluated how the phaseout of cyanazine will impact
users as compared to an immediate cancellation. Data and information
from publications of the USDA National Agricultural Statistical Service
(NASS), USDA/University State Extension Pesticide Use Recommendation
Reports, other proprietary marketing research sources, and comments
received in response to the triazine PD 1 were used as the basis for
this analysis. Although USDA National Agricultural Pesticide Impact
Assessment Program (NAPIAP) reports on field corn (1995), cotton
(1993), and sorghum (1994) exist, they have limited usefulness to EPA
in terms of quantitative estimates of impacts.
The NAPIAP reports generally contain estimates of yield losses and
direct costs resulting from the use of some alternative chemicals. The
NAPIAP report on corn also includes estimates of crop damage. The yield
loss estimates were based on a survey of regional weed scientists. For
the corn assessment, scientists from 15 states were interviewed as a
group to encourage dialogue. Survey responses were then used as a basis
for quantitative estimates of the economic impact of a cancellation of
cyanazine and substitution of alternative control methods. The report
does not specify the basis for the opinions of the weed scientists.
Thus, it is not clear to what extent the opinions of the weed
scientists are based on comparative product performance tests or other
comparable scientific data. The Agency has concluded that a reliable
projection of the comparative performance of pesticide products must
[[Page 8198]]
be based on scientifically derived data. Projections based solely on
opinions, even the opinions of experts, do not provide a sufficiently
reliable basis for the quantitative estimation of economic impacts.
Accordingly, the Agency has not relied on the NAPIAP reports to
estimate potential economic impacts of the cancellation or phaseout of
cyanazine registrations.
The NAPIAP reports are limited in several other respects. The
commodity assessments do not focus on cyanazine, nor do they address
specific aspects that could affect the impacts associated with its
anticipated phaseout. Additional factors that were not considered in
the NAPIAP reports include tillage practices, potential for crop
injury, farm size, and regional preferences that could also influence
the overall economic impacts to users. Perhaps most significantly, the
corn and cotton assessments were completed before several newly
registered herbicides entered the market, so they were not considered.
The Agency has not adopted the NAPIAP reports' quantitative
estimates of the economic impacts of a cancellation or phaseout, but
has used the reports for other purposes in the Agency's analysis. For
example, the NAPIAP reports do provide useful information about the
manner and extent of cyanazine use. The NAPIAP quantitative estimates
have been used only for the limited purpose of illustrating the
relative economic differences between the two regulatory options: a
complete cancellation or a phase-down of use followed by a complete
cancellation. In such an analysis, the accuracy and reliability of the
NAPIAP quantitative estimates are not crucial because the Agency is
using them for the limited purpose of illustrating the relative
relationship between the two regulatory options.
Because the terms and conditions of the cyanazine phaseout call for
incremental annual reductions in cyanazine usage beginning in 1997,
reaching a maximum of 1 lb/ai/a in 1999, and requirements for closed
cab application equipment beginning in 1998 and remaining throughout
the phaseout period, the full impacts of the cyanazine phaseout will
not be realized until after 2002, when all use of the chemical is
prohibited. However, the Agency does believe that some impacts will
occur during the phaseout period as a result of a decrease in the
maximum rates allowed per acre and the closed cab requirements.
Most cyanazine users are not expected to be adversely affected by
the phaseout until the maximum use rate drops below the rate at which
they are currently applying the chemical. For example, the majority of
cyanazine usage on corn is applied at rates between 1 and 3 lb/ai/acre.
Therefore, the use on corn will not be significantly affected until
1999 when the maximum rate is reduced to 1 lb/ai/acre. Similarly, for
cotton, the majority of usage occurs at rates of less than 1 lb/ai/a;
therefore, most uses in cotton will remain unaffected, assuming
adequate supplies, through 2002, at which time cyanazine will no longer
be available for use. Table 5 below presents the frequency distribution
of cyanazine acre treatments by application rate for each of the use
sites.
Table 5.--Distribution of Cyanazine Usage (Acre Treatments) by Application Rate (1993 - 1994)
----------------------------------------------------------------------------------------------------------------
Application Rate (lb/ai/acre) Field Corn Cotton Sweet Corn
----------------------------------------------------------------------------------------------------------------
0 to 1 18% 91% 16%
>1 to 3 72% 8% 81%
>3 to 5 9.8 1% 3%
>5 to 6.5 0.2% -- --
Total 100% 100% 100%
----------------------------------------------------------------------------------------------------------------
Source: U.S. EPA; Based on proprietary and publicly available
data.
The Agency acknowledges that some benefits are associated with the
use of cyanazine throughout the phaseout period; however, quantitative
estimates of the impact of the phaseout have not been determined. As
discussed earlier, the Agency has used the quantitative estimates of an
immediate cancellation as reported by NAPIAP for the limited purpose of
illustrating the relative differences between a phaseout of cyanazine
followed by a complete cancellation and an immediate cancellation. The
Agency has not relied on the NAPIAP reports to estimate the potential
economic impact of the phaseout and cancellation of cyanazine other
than to merely illustrate that a phaseout incurs less of an impact to
growers than would an immediate cancellation. The NAPIAP reports
estimate that the aggregrate economic impacts of an immediate ban of
cyanazine would be $25 million for corn and $14 million for cotton. In
Table 6, the NAPIAP estimates have been used to illustrate the
ameliorating effect that the phaseout of cyanazine may have on
individual uses (Ref. 12).
Table 6--Allocation of the Impacts of the Phaseout and Voluntary Cancellation of Cyanazine
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year App Rate (lb/ai/acre) Field Corn ($mil) Cotton ($mil) Sweet Corn ($mil) Total Impacts ($mil)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1996 6.5 $0.00 $0.00 $0.00 $0.00
1997 5 $0.05 $0.00 $0.00 $0.05
1998 3 $6.8 $8.6 $0.1 $15.5
1999 1 $21.4 $9.0 $0.7 $31.1
2000 1 $21.4 $9.0 $0.7 $31.1
2001 1 $21.4 $9.0 $0.7 $31.1
2002 1 $21.4 $9.0 $0.7 $31.1
2003 0 $25 $14 $0.8 $39.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 8199]]
While the Agency has used the NAPIAP quantitative estimates of
impacts in Table 6 above, the Agency neither accepts nor rejects them.
The quantitative estimates are used only to illustrate the relative
difference between immediate cancellation and a phaseout.
1. Field corn. Between 18 and 21 percent of the 73 million acres
planted to field corn receives one or more applications of cyanazine
per growing season at an average rate of 1.9 lb/ai/acre. Approximately
22 - 33 million pounds of cyanazine are applied annually. Treatments
are predominantly preemergence and preplant incorporated; however,
cyanazine combined with atrazine is commonly used in no-till corn as an
early post-emergence or burndown agent. Cyanazine is applied alone or
in combination with another herbicide approximately 35 and 65 percent
of the time, respectively. About 90 percent of cyanazine products are
applied broadcast using ground equipment and most of the remaining 10
percent applied as a band treatment. Cyanazine used alone is applied at
an average rate of 2.25 lb/ai/acre. When used in combination with
another herbicide, cyanazine is applied at an average rate of 1.67 lb/
ai/acre.
The majority of users who apply cyanazine to field corn will not be
affected until 1999 when the maximum use rate is lowered to 1 lb/ai/a.
However, about 10 percent of cyanazine usage does occur at rates of 3
lb/ai/acre or higher on heavier clay soils that generally contain
greater than 3 percent organic matter or on soils with greater than 30
percent surface residue. In 1999, when the maximum rate is reduced to 1
lb/ai/a, approximately 82 percent of cyanazine usage will be affected.
Compared to an immediate cancellation, the phaseout reduces annual
impacts because cyanazine will continue to be available to some growers
through 2002. Table 6 above illustrates the ameliorating effect that
the phaseout of cyanazine followed by a voluntary cancellation has on
corn growers relative to an immediate ban. Efficacious alternatives to
cyanazine include atrazine, nicosulfuron, metolachlor, alachlor,
dicamba, acetochlor, halosulfuron and prosulfuron.
2. Cotton. Cotton is the second largest crop on which cyanazine is
used and it accounts for 3 percent of the total cyanazine used in the
United States or about 1 - 2 million pounds of active ingredient. About
62 percent of cyanazine usage in cotton are postemergence directed
applications, 25 percent are preemergence applications and 11 percent
are layby applications. About 12 - 20 percent of the U.S. cotton
acreage received a cyanazine application at an average rate of 0.8 lb/
ai/a. Preplant applications were typically made at the rate of 1.5 -
2.0 lb/ai/acre while postemergence applications were made at the rate
of 0.5 - 1 lb/ai/a. Alternatives that are available for use on cotton
include diuron, fluometuron, oxyfluorfen, prometryn, and the recently
registered herbicide pyrithiobac-sodium. Since the majority of
cyanazine usage in cotton occurs at rates less than 1 lb/ai/a, the
phaseout should not adversely impact cotton growers until cyanazine use
is prohibited after 2002. Table 6 above illustrates the ameliorating
effect that the phaseout of cyanazine followed by a voluntary
cancellation has on cotton growers relative to an immediate ban.
3. Sweet Corn. Approximately 200,000 to 300,000 pounds active
ingredient of cyanazine is applied to sweet corn per year at an average
rate of 1.5 lb/ai/acre. About 6 percent of the 164,000 acres of fresh
market sweet corn and about 24 percent of the 503,000 acres of
processed sweet corn receive cyanazine applications, with Wisconsin,
Illinois, New York, Michigan, New Jersey, and Minnesota having
significant cyanazine use on this commodity. The heavy usage in
Wisconsin is probably due to the restrictions placed on atrazine in
that state. There are fewer alternative herbicides registered for use
on sweet corn than for field corn, with atrazine being the primary
preemergence alternative. Dicamba and 2,4-D are postemergence
alternatives for broadleaf weed control and alachlor and metolachlor
are alternatives for grass control.
As stated earlier, no published information was available that
estimated the impacts of the unavailability of cyanazine for sweet corn
production. The Agency calculated estimates for sweet corn based on
information that was available for field corn. The economic impact on
field corn is adjusted to account for differences between the total
acres planted and the per acre value of sweet corn and field corn. The
following formula is used to estimate this impact:
Sweet Corn Impact = Field Corn Impact ($25 million) x total acres
sweet corn (800,000)/total acres field corn (70,000,000) x per acre
value sweet corn ($850)/per acre value field corn ($303).
The per acre value of sweet corn is a weighted average of sweet
corn grown for the fresh market (224,900 acres, $373.7 million) and the
processed market (516,200 acres, $256.1 million). The per acre value of
field corn was calculated on the basis of 72.9 million acres with a
total crop value of $22.16 billion. Using the above formula, the annual
economic impact of banning cyanazine use on sweet corn is estimated to
be $0.8 million. Annual impacts that result from the phaseout of
cyanazine will not significantly impact sweet corn growers until 1999
when the maximum allowable application rate is reduced to 1 lb/ai/a.
Wisconsin sweet corn growers may be severely impacted by the
phaseout of cyanazine since it is believed that a large percentage of
cyanazine usage in that state is a result of the state restrictions
that have been placed on atrazine. In some counties, rate restrictions
have reduced the performance of atrazine as a preemergence treatment.
Therefore, sweet corn growers may have to resort to using postemergence
herbicides to control broadleaf weeds unless new preemergence
herbicides are registered. The Agency anticipates that the impact to
sweet corn growers will be similar to that anticipated for field corn
growers. Table 6 above illustrates the ameliorating effect that the
phaseout of cyanazine followed by a voluntary cancellation has on sweet
corn growers relative to an immediate ban.
Comments Regarding Benefits of Cyanazine and the Agency's Response
A number of commenters, including academia and weed extension
scientists, grower groups, and chemical producers, submitted comments
about the general benefits of cyanazine use in agricultural practices.
These general arguments support cyanazine's continued use because of
its shorter residual life and therefore less crop rotation
restrictions, better control of certain grass weeds other than
triazines, effectiveness against germinating and emerged weeds with
good burndown action in no-till practices, role in weed resistance
management, no drift damage to sensitive crops nearby, and its
generally greater flexibility in weed control programs. The Agency
acknowledges that there are certain benefits associated with the use of
cyanazine and, as required, has considered all of cyanazine's
advantages in its assessments.
Comment: NCAMP and EWG criticized the methodology of the Agency's
analyses of pesticide benefits. NCAMP commented that a comprehensive
benefits assessment will demonstrate the appropriateness of cancelling
all registrations of the triazines. NCAMP further stated that the
Agency's method of assessing benefits is inappropriate because the
assessment looks only at
[[Page 8200]]
alternative chemical means of controlling weed pests. The EWG commented
that the Agency must consider the total social costs of using
pesticides in its benefits assessment and that it is not proper to
allow a chemical risk to support the production of commodities that are
subsidized and where supply exceeds demand.
Agency Response: Because these comments were not specific to cyanazine,
the Agency intends to respond to them later in the Special Review when
comments on all triazines are addressed, unless it receives additional
comments demonstrating that these criticisms apply specifically to
cyanazine.
Comment: Griffin provided an assessment of the general benefits of
cyanazine that addressed the following aspects of cyanazine: (1)
Importance in controlling a wide spectrum of weeds, (2) providing
greater crop rotation flexibility, (3) usefulness in no-till practices,
(4) weed resistance management, and (5) lower cost than alternative
chemicals.
Agency Response: The Agency agrees with Griffin that cyanazine offers
those benefits as Griffin pointed out; however, the Agency also
believes that alternative herbicides are available that provide
comparable weed control at similar costs. Earlier in this Notice, the
Agency acknowledged many of the same advantages of using cyanazine as
Griffin noted.
VI. Risk/Benefit Analysis and the Agency's Proposed Decision
Regarding Special Review
A. Risks
The terms and conditions of the phaseout and cancellation are
expected to reduce risk from use of cyanazine as estimated in the
cyanazine PD 1 to zero over the course of the phaseout and depletion of
existing stocks. While both users and the public will be subject to
some continued risk during this time, the risk to users will decline
during the phaseout and depletion of existing stocks due to the
imposition of use restrictions and the risk to the public will decline
due to the reduction in use rates.
B. Benefits
In Unit V. of this Notice, a discussion of the impacts of phasing
out cyanazine compared to an immediate cancellation is presented. The
cyanazine phaseout allows for a gradual reduction in use of the
chemical over a period of 7 years.
There are a number of elements inherent in the phaseout of
cyanazine that will, in effect, lessen the economic impact to growers
who have used cyanazine in their weed management practices in the past.
First, the phaseout should allow growers sufficient time to find
suitable alternatives to replace cyanazine, thereby causing little
disruption to agricultural production. For example, the majority of
cyanazine used is applied to field corn. With the phaseout, there will
be little impact to corn growers until 1999 when the maximum allowable
use rate drops to 1 lb/ai/a. With all uses, the full impact of the
phaseout will not be realized until after 2002 when cyanazine use will
be prohibited.
C. Risks of Alternatives
The Agency has identified the major chemical alternatives to
cyanazine in this Notice. Atrazine, one alternative to cyanazine, was
placed into Special Review concurrently with cyanazine based on the
potential risk of carcinogenicity to humans. No significant risk
concerns have been identified with the other alternatives except for
2,4-D, which is currently being considered for possible Special Review
pending results of further studies on its carcinogenic potential.
D. Risk/Benefit Analysis
In light of the terms and conditions of the DuPont and Griffin
cyanazine registrations, the Agency has considered the risks and
benefits of cyanazine for the remaining 7 years that the pesticide will
be allowed for use. During the phaseout, people will be exposed to
cyanazine for a limited time period during which application rates will
be reduced and closed cab application equipment will be required. As
discussed earlier, the Agency believes that the potential risks that
may result, while considering the factors of time and exposure imposed
by the cyanazine phaseout, will be less than those risks articulated in
the PD 1. Further, the Agency has evaluated the impacts of the
cyanazine phaseout and has concluded that there are benefits associated
with the phaseout of cyanazine.
The phaseout also confers benefits by making it unnecessary to
recall and dispose of unused product and by allowing users to reduce
costs through various mechanisms such as allowing them time to
gradually modify weed management strategies to replace cyanazine. The
Agency also considered the costs, time, and uncertainties associated
with involuntary imposition of regulatory measures. In the absence of
the voluntary cancellation and phaseout, the Agency may have used its
authority under FIFRA section 6 to cancel cyanazine registrations. The
Agency believes that this action would have been contested and would
have required enormous resources and several years of litigation before
a final order could have been implemented. The resources saved by
voluntary cancellation and phaseout may now be applied to risk
reduction of other products. Also, a contested cancellation would not
have brought about the phased-in measures to reduce risk as currently
provided for by the terms and conditions of the voluntary cancellation
and phaseout. Finally, the outcome of litigation is uncertain in both
result and when those results may be achieved; the voluntary
cancellation and phaseout has set a firm schedule for the
implementation of risk reduction measures and has established a date
certain for the final cancellation of cyanazine registrations.
For all of the foregoing reasons, the Agency has determined that
implementation of the voluntary cancellation and phaseout of cyanazine
will eliminate the potential risks posed by cyanazine identified in the
triazine PD 1.
E. Proposed Decision Regarding Special Review
In view of its determination discussed above, that the terms and
conditions of the cyanazine voluntary cancellation and phaseout will
eliminate any unreasonable adverse effects posed by the registration of
cyanazine, the Special Review need not be continued.
VII. Request for Voluntary Cancellation
As part of the terms and conditions of all registered cyanazine
products, including those of both DuPont and Griffin, voluntary
cancellations of all cyanazine registrations will become effective
December 31, 1999. Shortly thereafter, the Agency will issue a
cancellation order for all cyanazine products. Also, as part of the
terms and conditions, EPA is required to provide advance public
notification of the voluntary cancellation of cyanazine products as
part of the proposal to terminate the Special Review of cyanazine. This
section, Unit VII., will serve as the Agency's notification of the
requests for voluntary cancellation.
The cyanazine products that, according to the amended terms and
conditions of cyanazine registration, will be voluntarily canceled,
effective December 31, 1999, are listed below by EPA registration
number and product name.
[[Page 8201]]
Registration No. Product Name
352-475 DuPont Cyanazine Technical
352-470 DuPont Bladex (R)4L Herbicide
352-495 DuPont Bladex (R)90 DF
Herbicide
352-500 DuPont Extrazine (R)II 4L
Herbicide
352-577 DuPont Extrazine (R)II DF
Herbicide
1812-364 Griffin Cyanazine Technical
1812-365 Griffin Cynex DF
1812-366 Griffin Cynex 4L Herbicide
Liquid
1812-367 Griffin Cynex Extra 4L
1812-368 Griffin Cynex Extra DF
Comments on the requests for voluntary cancellation of these
registrations may be submitted to the contact person listed under the
FOR FURTHER INFORMATION CONTACT unit of this document during the 30-day
comment period provided in this Notice.
Also included in the terms and conditions of cyanazine
registrations is a provision for allowing the continued distribution
and use of cyanazine end use products beyond the effective voluntary
cancellation date. The terms and conditions specifically state that all
cyanazine formulated end use products released for shipment by a
registrant on or before December 31, 1999, may continue to be
distributed and sold in the channels of trade in accordance with labels
through September 30, 2002. The terms and conditions further state that
use of such existing products in accordance with their labels may
continue through December 31, 2002. All labels of cyanazine formulated
end use products released for shipment by a registrant after July 25,
1996, will state that the product may not be sold or distributed after
September 30, 2002, and that the products may not be used after
December 31, 2002. The existing stocks provision will allow any
remaining product in the channels of trade to be used, thereby
precluding the need for recall and disposal of unused product.
VIII. Public Comment Opportunity
During the 30-day comment period, specific comments are requested
on the Agency's preliminary determination to terminate the Special
Review of cyanazine and on the requests for voluntary cancellation of
cyanazine products. The Agency will review and consider any comments
received during the official comment period before issuing a final
determination on conclusion of the Special Review of cyanazine. All
written comments submitted pursuant to this Notice, except ``CBI,''
will be available for public inspection in Rm. 1132, CM #2, 1921
Jefferson Davis Highway, Arlington, VA Telephone: 703-308-5805.
Comments claimed as CBI must be clearly marked as ``confidential,''
``trade secret,'' or other appropriate designation on the face of the
comments. Comments marked as such will be treated in accordance with
the procedures in 40 CFR 2.204(e)(4). Comments not claimed as
confidential at the time of submission, or not clearly labeled as
containing CBI, will be placed in the public docket. The Agency will
consider the failure to clearly identify the claimed confidential
status on the face of the comment as a waiver of such claim, and will
make such information available to the public without further notice to
the submitter.
All comments and information should be submitted in triplicate to
the address given in this Notice under ADDRESSES to facilitate the work
of EPA and others interested in inspecting them. The comments and
information should bear the docket control number, ``OPP-30000/60A.''
IX. Public Docket
A record has been established for the action under docket number
``OPP-30000/60A'' (including comments and data submitted electronically
as described below). A public version of this record, including
printed, paper versions of electronic comments, which does not include
any information claimed as CBI, is available for inspection from 8 a.m.
to 4:30 p.m., Monday through Friday, excluding legal holidays. The
public record is located in Rm. 1132 of the Public Response and Program
Resources Branch, Field Operations Division (7506C), Office of
Pesticide Programs, Environmental Protection Agency, Crystal Mall #2,
1921 Jefferson Davis Highway, Arlington, VA.
Electronic comments can be sent directly to EPA at:
opp-docket@epamail.epa.gov
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption.
The official record for the document, as well as the public
version, as described above will be kept in paper form. Accordingly,
EPA will transfer all comments received electronically into printed,
paper form as they are received and will place the paper copies 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.
X. Terms and Conditions Amending Cyanazine Registrations
On August 2, 1995, EPA accepted DuPont's proposed amendments to its
cyanazine registrations that effectively phases out the production of
cyanazine for use in the United States by the end of 1999. The
amendments also included an incremental reduction of the maximum label
rates over the course of the phaseout and a requirement for closed cab
application equipment in 1998. The terms and conditions of the
amendments apply to all current DuPont cyanazine registrations as well
as any new registration that the Agency may approve since the
acceptance of DuPont's proposal, including Griffin's recent conditional
registrations that were approved by the Agency. As part of the
requirements for approval of any future cyanazine registrations, any
registrant must agree to comply with all of the same terms and
conditions to effectively phaseout cyanazine production for use in the
United States by end of 1999. The amended terms and conditions that are
required of all cyanazine registrants appear below.
Terms and Conditions to Amend Cyanazine Registrations
1. On November 23, 1994, the U.S. Environmental Protection
Agency (``EPA'') initiated a Special Review under the Federal
Insecticide, Fungicide, and Rodenticide Act (``FIFRA''), for
pesticide products that contain a triazine herbicide as an active
ingredient, Federal Register Notice, Vol. 59, No. 225 (``the Special
Review''). Cyanazine is one of the triazine products subject to the
Special Review, and E. I. du Pont de Nemours and Company
(``DuPont'') is the primary registrant of cyanazine in the United
States.
2. EPA's initiation of the Special Review for triazine
containing products was based on the Agency's preliminary
determination that triazine products trigger risk criteria that
indicate these products may present unreasonable risks as described
in the Notice of Special Review. This preliminary determination by
EPA with respect to cyanazine, however, is not a finding, conclusion
or other determination, that cyanazine does in fact present a risk
to humans or the environment.
3. The purpose of this letter is to propose a comprehensive
listing of the terms and conditions of amendments to DuPont's
cyanazine product registrations. The specific mitigation steps
proposed in these amendments are designed to reduce the potential
for the risk criteria being triggered in the future and to
satisfactorily address EPA's concerns over potential risks as
described in the Notice of Special Review. DuPont's understanding in
agreeing to the
[[Page 8202]]
proposed mitigation steps is that if they are required of all current
and potential future cyanazine-containing products and
registrations, including but not limited to DuPont's cyanazine
products and registrations, they will adequately address EPA's
concerns that cyanazine products may present risks as described by
EPA in the Notice of Special Review. It is DuPont's further
understanding that based on this determination, EPA will proceed to
conclude the Special Review as to cyanazine as soon as practicable.
4. DuPont's agreement to the proposed amendments set forth
herein is not, and shall not be considered as, an admission by
DuPont that cyanazine used in accordance with DuPont's registrations
and labels triggers risk criteria as described in the Notice of
Special Review, or otherwise poses risks to humans or the
environment.
5. Cyanazine Risk Mitigation Measures shall be comprised of the
following steps: (a) The labels of all cyanazine formulated end use
products released for shipment by a registrantl after July 25,
1996, for use in the U.S., shall specify seasonal use rates that
limit the maximum amount of cyanazine active ingredient that may be
applied on a per acre basis as follows:
1For the purpose of determining compliance with the proposed
terms and conditions of amended registrations as set forth in
paragraph 5., whenever the term ``released for shipment by a
registrant appears in these amendments, it shall mean the shipment
of cyanazine formulated end use products, shipped by or at the
direction of a registrant from the facility at which they are
finally formulated for distribution, sale and use in the U.S. as
evidenced by a bill of lading or other verifiable shipping
documents. The term shall not apply to a) shipments of cyanazine
formulated end use products by agents, distributors, or dealers who
receive and further distribute cyanazine products to customers, or
b) to cyanazine technical products shipped within the U.S. for
formulation into end use products, or c) to shipments of cyanazine
technical or formulated end use products for export. Any formulated
end use product containing cyanazine technical products and
registered for use in the U.S. shall be subject to the terms and
conditions of paragraph 5 of this letter.
---------------------------------------------------------------------------
FOR USE: MAXIMUM SEASONAL USE RATE CAP (AI/ACRE):
Beginning Jan. 1, 1997 5 lbs per acre
Beginning Jan. 1, 1998 3 lbs per acre
Beginning Jan. 1, 1999 1 lb per acre
(b) Subject to all the terms and conditions of these amendments,
this letter shall serve as DuPont's request, pursuant to FIFRA, that
EPA accept the voluntary cancellation of all of DuPont's existing
registrations for formulated end use products containing cyanazine
to become effective December 31, 1999. The cancellation date of
December 31, 1999, shall become a part of the terms and conditions
of DuPont's registrations for formulated end use products that
contain cyanazine.
(c) The labels of all cyanazine products released for shipment
by a registrant after July 25, 1996, for use in the U.S., shall
specify that closed cab application will be required for
applications to be made during or after the 1998 use season.
(d) No cyanazine formulated end use products registered for use
in the U.S. shall be released for shipment by a registrant after
December 31, 1999.
(e) EPA shall authorize existing stocks of all cyanazine
formulated end use products that have been released for shipment by
a registrant of such products on or before December 31, 1999, to
continue to be distributed and sold in the channels of trade in
accordance with their labels through September 30, 2002. EPA shall
authorize the continued use of such existing stocks in accordance
with their labels through December 31, 2002. Labels of all cyanazine
formulated end use products released for shipment by a registrant
after July 25, 1996, shall bear the following statements: ``This
product may not be sold or distributed after September 30, 2002''
``This product may not be used after December 31, 2002.''
(f) The public will have advance notification of the voluntary
cancellation of DuPont's cyanazine formulated end use registrations
and the existing stocks provisions provided for herein as part of
the conclusion of the Special Review, and DuPont shall have no
obligation to recover or recall any cyanazine products, or to
reimburse, or otherwise compensate or provide additional notice to
any purchaser or other party in connection with or as a result of
the voluntary cancellation provided for herein.
(g) cyanazine technical products released for shipment by a
registrant after July 25, 1996, shall bear labels stating that any
formulated end use products that are made from the technical
products and that are registered for use in the U.S., shall be
subject to the terms and conditions of cyanazine registrations set
forth in paragraph 5 of this letter.
6.(a) It is DuPont's understanding that upon its submission to
EPA of a signed copy of this letter proposing amendments to its
registrations, EPA will commence such steps as are necessary to
approve finally the amendments and to conclude the Special Review of
cyanazine, without requiring further mitigation steps by DuPont, and
that EPA will complete such final Agency action, including any
public comment or required notice to other federal agencies, as soon
as practicable. In the event EPA is unable to so approve the
amendments or to finally conclude the Special Review, for whatever
reason, or if after August 2, 1995, and prior to the date EPA
finally approves these amendments and finally concludes the Special
Review, another party obtains a cyanazine registration that does not
contain the terms and conditions set forth in these amendments, for
whatever reason, these amendments may, at DuPont's election, be
withdrawn and be without effect, and the current terms and
conditions of DuPont's cyanazine registrations shall remain in
effect. In such event, DuPont will retain all of its rights to
participate fully in the Special Review, or any Agency or judicial
review of the same, or to contest any regulatory action that may be
initiated against its products and registrations, pursuant to FIFRA
or other applicable laws and regulations, as it deems appropriate.
(b) In the event another party obtains a registration of a
cyanazine product that does not require the terms and conditions of
registration as specified in this letter, including cancellation as
of December 31, 1999, or said terms and conditions are proposed or
imposed upon another party's registrations, but are stayed or
enjoined in whole or in part by the Agency or any court, EPA agrees
to permit DuPont to continue its registrations in effect beyond
December 31, 1999, and/or amend its cyanazine registrations, on a
specific use and/or site specific or use rate basis, in order to
delete any term or condition of registration set forth in this
letter that is not required of the other party or as a term or
condition of that party's registration, and to make such other
amendments to its cyanazine registrations, including but not limited
to adding new uses or application methods, as are necessary so that
DuPont's cyanazine registrations may contain the same terms and
conditions as are contained in the other party's registrations. Any
such amendments are to be accomplished in accordance with the
requirements of FIFRA.
7. On April 16, 1992, EPA issued a Data Call In for cyanazine
(the ``DCI''). DuPont has completed and submitted all of the studies
requested in the DCI. EPA agrees that DuPont has submitted all of
the studies requested by the DCI, and that EPA will not request
further data from DuPont in connection with said DCI. Nothing
contained in these amendments shall be interpreted as restricting
EPA's authority to issue a future Data Call In, or otherwise to
regulate cyanazine registrations pursuant to FIFRA, should the
Agency determine that there is significant new evidence about
potential unreasonable risks to the environment presented by use of
products containing cyanazine. DuPont shall retain all of its rights
under FIFRA and other applicable laws and regulations to challenge
any such action by EPA.
8. Upon EPA's final acceptance of these amendments, and the
Agency's final action concluding the Special Review in accordance
with the amendments and understandings set forth herein, DuPont
agrees to waive its rights to challenge EPA's final action on the
Special Review, or the terms and conditions of label amendments that
are required by these amendments, in any court or administrative
forum, and agrees not to assist or encourage any other party to
challenge EPA's final actions. Except as expressly set forth in
these amendments, DuPont shall retain all of its rights under FIFRA,
and other applicable laws and regulations, to challenge any action,
proceeding or determination by EPA, or to challenge or intervene in
any action by or involving a third party, with respect to the
registration of DuPont's or any other party's cyanazine products.
XI. References
1. U.S. Environmental Protection Agency. Notice of Receipt of
Requests to Voluntarily Cancel Certain Registrations. Federal Register
Notice (60 FR 56333). November 8, 1995.
2. U.S. Environmental Protection Agency. Atrazine, Simazine, and
Cyanazine; Notice of Initiation of Special Review. Federal Register
Notice (59 FR 60412). November 23, 1994.
[[Page 8203]]
3. U.S. Environmental Protection Agency. Letter from Lynn R.
Goldman to Jane D. Brooks, Dupont Agricultural Products. August 2,
1995.
4. U.S. Environmental Protection Agency. Notice of Pesticide
Registration. November 6, 1995.
5. U.S. Environmental Protection Agency. Notice of Pesticide
Registration. September 18, 1995.
6. U.S. Environmental Protection Agency. Notice of Pesticide
Registration. February 8, 1996.
7. U.S. Environmental Protection Agency. Notice of Pesticide
Registration. February 9, 1996.
8. U.S. Environmental Protection Agency. Notice of Pesticide
Registration. February 12, 1996.
9. U.S. Environmental Protection Agency. Memorandum from Denise
Keehner, Office of Pesticide Programs, Environmental Fate and Effects
Division. Transmittal of EFED Review of Comments Including DuPont's on
the PD 1 Related to Ground Water and Surface Water for Cyanazine.
November 3, 1995.
10. DuPont Agricultural Products. Letter from Tony E. Catka.
``Cyanazine Mixer/Loader/Applicator Occupational Cancer Risk
Estimates.'' October 19, 1994.
11. U.S. Environmental Protection Agency. Memorandum from Olga
Odiott, Office of Pesticide Programs, Health Effects Division.
``DuPont's Cyanazine Occupational Exposure Estimates.'' October 26,
1995.
12. U.S. Environmental Protection Agency. Biological and Economic
Assessment of the Cyanazine Phaseout. February 9, 1996.
Dated: February 26, 1996.
Lynn R. Goldman,
Assistant Administrator for Prevention, Pollution and Toxic Substances.
[FR Doc. 96-4963 Filed 2-29-96; 8:45 am]
BILLING CODE 6560-50-F
