02-16643. NESHAP: Standards for Hazardous Air Pollutants for Hazardous Waste Combustors (Final Replacement Standards and Phase II)-Notice of Data Availability

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of data availability.

SUMMARY:

This notice of data availability (NODA) presents for public comment the data bases the Environmental Protection Agency plans to use to propose National Emission Standards for Hazardous Air Pollutants (NESHAP) for hazardous waste burning combustors (incinerators, cement kilns, lightweight aggregate kilns, industrial and commercial/institutional boilers, process heaters, and hydrochloric acid production furnaces). We are providing this opportunity for comment to ensure that the data bases used to establish the standards are as accurate and complete as possible.

DATES:

Comments must be submitted by August 16, 2002.

ADDRESSES:

Comments may be submitted electronically, by mail, by facsimile, or through hand delivery/courier. If you wish to comment on this NODA, you must send an original and two copies of the comments referencing Docket Number RCRA-2002-0019 to: RCRA Information Center (RIC), Office of Solid Waste (5305G), U.S. Environmental Protection Agency Headquarters (EPA HQ), Ariel Rios Building, 1200 Pennsylvania Avenue, NW., Washington, DC 20460-0002; or, (2) if using special delivery, such as overnight express service: RIC, Crystal Gateway One, 1235 Jefferson Davis Highway, First Floor, Arlington, VA 22202. You may also submit comments electronically following the directions in the SUPPLEMENTARY INFORMATION section below.

You may view the data bases in the RIC. The RIC is open from 9 am to 4 pm Monday through Friday, excluding Federal holidays. To review docket materials, we recommend that you make an appointment by calling 703-603-9230. You may copy up to 100 pages from any regulatory document at no charge. Additional copies cost $ 0.15 per page. For information on accessing an electronic copy of the data bases, see the SUPPLEMENTARY INFORMATION section.

FOR FURTHER INFORMATION CONTACT:

For general information, call the RCRA Hotline at 1-800-424-9346 or TDD 1-800-553-7672 (hearing impaired). Callers within the Washington Metropolitan Area must dial 703-412-9810 or TDD 703-412-3323 (hearing impaired). The RCRA Hotline is open Monday-Friday, 9 am to 6 pm, Eastern Standard Time. For more information on specific aspects of this NODA, contact Frank Behan at 703-308-8476, or [e-mail], or write him at the Office of Solid Waste, 5302W, U.S. EPA, Ariel Rios Building, 1200 Pennsylvania Avenue, NW, Washington, DC 20460.

SUPPLEMENTARY INFORMATION:

Acronyms Used in this Notice

APCD—Air pollution control device

BH—Baghouse

BIF—Boiler and industrial furnaces

CAA—Clean Air Act

CFR—Code of Federal Regulations

D/F—dioxins and furans

EPA—United States Environmental Protection Agency

ESP—Electrostatic precipitator

FR—Federal Register

HAP—Hazardous air pollutant

HCl—Hydrochloric acid

HWC—Hazardous waste combustor

LVM—Low Volatile Metals

MACT—Maximum achievable control technology

NESHAP—National emission standards for hazardous air pollutants

NODA—Notice of data availability

PM—Particulate matter

RCRA—Resource Conservation and Recovery Act

SVM—Semivolatile Metals

Table of Contents

I. General Information

A. How Can I Get Copies Of The Data Bases?

B. How and To Whom Do I Submit Comments?

C. How Should I Submit CBI To the Agency?

D. What Should I Consider as I Prepare My Comments for EPA?

II. What Is the Purpose of this NODA?

III. Are You Affected by this Notice?

IV. What Led Up to this NODA?

V. What Data Are Included in this Notice?

VI. What Data Handling Decisions Did We Make and What Are the Data Gaps?

A. Data from Sources No Longer Burning Hazardous Waste Are Excluded

B. How Are Nondetect Data Handled?

C. Missing Source Description Information

D. Use of Metals Extrapolation, Interpolation and Surrogates

VII. What Are the New Data Comment Fields?

A. What Information Do We Need to Consider Subcategorization Options?

B. How Will We Distinguish Between Worst-Case and Normal Emissions?

C. What Classifications Do We Use to Address Sootblowing by Boilers?

I. General Information

A. How Can I Get Copies Of The Data Bases?

1. The Docket

EPA has established an official public docket for this action under Docket ID RCRA-2002-0019. The official public docket consists of the documents specifically referenced in this action, any public comments received, and other information related to this action. Although a part of the official docket, the public docket does not include Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. The official public docket is the collection of materials that is available for public viewing at the address above.

2. Electronic Access

You may access this Federal Register document electronically through the EPA Internet under the Federal Register listings at http://www.epa.gov/​fedrgstr/​. An electronic version of the public docket is available through EPA's electronic public docket and comment system, EPA Dockets. You may use EPA Dockets at http://www.epa.gov/​edocket/​ to submit or view public comments, access the index listing of the contents of the official public docket, and to access those documents in the public docket that are available electronically. Once in the system, select “search,” then key in the appropriate docket identification number.

Certain types of information will not be placed in the EPA Dockets. Information claimed as CBI and other information whose disclosure is restricted by statute, which is not included in the official public docket, will not be available for public viewing in EPA's electronic public docket. EPA's policy is that copyrighted material will not be placed in EPA's electronic public docket but will be available only in printed, paper form in the official public docket. To the extent feasible, publicly available docket materials will be made available in EPA's electronic public docket. When a document is selected from the index list in EPA Dockets, the system will identify whether the document is available for viewing in EPA's electronic public docket. Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the docket facility identified in section I.B. EPA intends to work towards providing electronic access to all of the publicly available docket materials through EPA's electronic public docket.

For public commenters, it is important to note that EPA's policy is that public comments, whether submitted electronically or in paper, will be made available for public viewing in EPA's electronic public docket as EPA receives them and without change, unless the comment contains copyrighted material, CBI, or other information whose disclosure is restricted by statute. When EPA identifies a comment containing copyrighted material, EPA will provide a reference to that material in the version of the comment that is placed in EPA's electronic public docket. The entire printed comment, including the copyrighted material, will be available in the public docket.

Public comments submitted on computer disks that are mailed or delivered to the docket will be transferred to EPA's electronic public docket. Public comments that are mailed or delivered to the Docket will be scanned and placed in EPA's electronic public docket. Where practical, physical objects will be photographed, and the photograph will be placed in EPA's electronic public docket along with a brief description written by the docket staff.

For additional information about EPA's electronic public docket visit EPA Dockets online or see 67 FR 38102, May 31, 2002.

3. Obtaining the Data Bases Electronically from the HWC Web Site

The data bases can be obtained either as described above, or by downloading from the EPA HWC site on the Internet. If you want to download the data bases over the Internet, you can do so from our “HWC MACT” Web site: http://www.epa.gov/​hwcmact. Please consult the web page for specific instructions on how to download the data bases. Do not, however, submit comments to this web address. Instead, follow the instructions provided below.

B. How and To Whom Do I Submit Comments?

You may submit comments electronically, by mail, by facsimile, or through hand delivery/courier. To ensure proper receipt by EPA, identify the appropriate docket identification number in the subject line on the first page of your comment. Please ensure that your comments are submitted within the specified comment period. Comments received after the close of the comment period will be marked “late.” EPA is not required to consider these late comments.

If you submit an electronic comment as prescribed below, EPA recommends that you include your name, mailing address, and an e-mail address or other contact information in the body of your comment. Also include this contact information on the outside of any disk or CD ROM you submit, and in any cover letter accompanying the disk or CD ROM. This ensures that you can be identified as the submitter of the comment and allows EPA to contact you in case EPA cannot read your comment due to technical difficulties or needs further information on the substance of your comment. EPA's policy is that EPA will not edit your comment, and any identifying or contact information provided in the body of a comment will be included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment.

1. EPA Dockets

Your use of EPA's electronic public docket to submit comments to EPA electronically is EPA's preferred method for receiving comments. Go directly to EPA Dockets at http://www.epa.gov/​edocket,, and follow the online instructions for submitting comments. To access EPA's electronic public docket from the EPA Internet Home Page, select “Information Sources,” “Dockets,” and “EPA Dockets.” Once in the system, select “search,” and then key in Docket ID No. RCRA-2002-0019. The system is an “anonymous access” system, which means EPA will not know your identity, e-mail address, or other contact information unless you provide it in the body of your comment.

2. E-mail

Comments may be sent by electronic mail (e-mail) to [e-mail], Attention Docket ID No. RCRA-2002-0019. In contrast to EPA's electronic public docket, EPA's e-mail system is not an “anonymous access” system. If you send an e-mail comment directly to the Docket without going through EPA's electronic public docket, EPA's e-mail system automatically captures your e-mail address. E-mail addresses that are automatically captured by EPA's e-mail system are included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket.

3. Disk or CD ROM

You may submit comments on a disk or CD ROM that you mail to the mailing address identified in the ADDRESSES section. These electronic submissions will be accepted in WordPerfect or ASCII file format. Avoid the use of special characters and any form of encryption.

C. How Should I Submit CBI To the Agency?

Do not submit information that you consider to be CBI electronically through EPA's electronic public docket or by e-mail. Send or deliver information identified as CBI only to the following address: RCRA CBI Document Control Officer, Office of Solid Waste (5305W), U.S.EPA, 1200 Pennsylvania Avenue NW., Washington, DC 20460, Attention Docket ID No. RCRA-2002-0019. You may claim information that you submit to EPA as CBI by marking any part or all of that information as CBI (if you submit CBI on disk or CD ROM, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is CBI). Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

In addition to one complete version of the comment that includes any information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket and EPA's electronic public docket. If you submit the copy that does not contain CBI on disk or CD ROM, mark the outside of the disk or CD ROM clearly that it does not contain CBI. Information not marked as CBI will be included in the public docket and EPA's electronic public docket without prior notice. If you have any questions about CBI or the procedures for claiming CBI, please consult the person identified in the FOR FURTHER INFORMATION CONTACT section.

D. What Should I Consider as I Prepare My Comments for EPA?

You may find the following suggestions helpful for preparing your comments:

1. Explain your views as clearly as possible.

2. Describe any assumptions that you used.

3. Provide any technical information and/or data you used that support your views.

4. If you estimate potential burden or costs, explain how you arrived at your estimate.

5. Provide specific examples to illustrate your concerns.

6. Offer alternatives.

7. Make sure to submit your comments by the comment period deadline identified.

8. To ensure proper receipt by EPA, identify the appropriate docket identification number in the subject line on the first page of your response. It would also be helpful if you provided the name, date, and Federal Register citation related to your comments.

II. What Is the Purpose of this NODA?

This NODA affects owners and operators of hazardous waste burning incinerators, cement kilns, lightweight aggregate kilns, industrial and institutional/commercial boilers, process heaters, and hydrochloric acid production furnaces. We are providing this NODA to request comment on data bases that we will use to develop proposed standards under Section 112(d) (i.e., MACT standards) for these source categories and subcategories.

We view publication of this NODA as a critical component of our quality assurance program that we are using to ensure and maximize the quality, objectivity, utility, and integrity of information that we plan to use in our future MACT rule making. Section 515 of the Treasury and General Government Appropriations Act for FY2001 (Pub. L. 106-554) directed OMB to issue government-wide information quality guidelines. The OMB guidelines were first issued on September 28, 2001. Pursuant to those guidelines EPA is developing its own guidelines. EPA's information quality guideline development program can be found on the World Wide Web at this URL: http://www.epa.gov/​oei/​qualityguidelines. One of the important components of EPA's draft Information Quality Guidelines is to provide the public with an opportunity and vehicle for correcting any errors that might be present in data and information that the agency is using in its decision-making. This NODA provides such an opportunity.

III. Are You Affected by this Notice?

We anticipate that we will develop revised MACT standards for hazardous waste burning incinerators, cement kilns, and lightweight aggregate kilns, as defined at 40 CFR 63.1201(a), and that are currently subject to MACT standards at 40 CFR part 63, subpart EEE.

We also plan to develop MACT standards for boilers, as defined at 40 CFR 260.10, that burn hazardous waste as defined at 40 CFR part 261. This definition of boiler includes devices used in industry as process heaters. These boilers are currently subject to regulation under 40 CFR part 266, subpart H, which is commonly referred to as the Boiler and Industrial Furnace (BIF) rule.

Please note that the MACT standards for hazardous waste burning boilers and process heaters would apply to boilers that are currently exempt from certain BIF emission standards under § 266.109 (Low Risk Waste Exemption) and § 266.110 (Waiver of DRE Trial Burn for Boilers). We anticipate, however, that we will propose that boilers currently exempt from part 266, Subpart H, because they qualify for the Small Quantity On-Site Burner Exemption, would not be subject to the MACT standards that we are developing for boilers that burn hazardous waste. Instead, we anticipate proposing that those boilers would be subject to MACT standards the Agency is developing for industrial and institutional/commercial boilers, and process heaters, that do not (otherwise) burn hazardous waste. Those boilers would be subject to MACT standards for boilers and process heaters that do not burn hazardous waste because their nonhazardous waste fuels will dictate the types and concentrations of HAP emissions rather than the de minimis quantities of hazardous waste fuel that they burn. The MACT standards for industrial and institutional/commercial boilers and process heaters that do not burn hazardous waste are scheduled to be proposed in late 2002.

Finally, we are also developing MACT standards for HCl production furnaces that burn hazardous waste. These furnaces are a type of halogen acid furnace included within the definition of “industrial furnace” defined at § 260.10 and are currently regulated under 40 CFR part 266, subpart H.

We do not anticipate proposing MACT standards for hazardous waste burning sulfur recovery furnaces. These industrial furnaces are subject to the BIF rule if they burn hazardous waste other than spent sulfuric acid either for energy recovery or to recover sulfur values. We do not believe MACT standards are warranted for these sources because available emissions data indicate that emissions of hazardous air pollutants are very low. In addition, the Agency has not listed these furnaces as a category of major sources. See 57 FR 31576, July 16, 1992. Sulfur recovery furnaces burning hazardous waste other than spent sulfuric acid would remain subject to the BIF rule.

IV. What Led Up to This NODA?

Congress amended the Clean Air Act (CAA) in 1990 to require that hazardous air pollutants be controlled by technology-based standards—standards based on the technical capabilities of control strategies for the emitting industry in question, with further controls required later if significant risk remains after imposition of the technology-based standards. These standards would apply to the HWCs discussed in this notice.

On September 30, 1999, we promulgated standards (referred to as the “Phase I” rule, 64 FR 52828) to control emissions of hazardous air pollutants from incinerators, cement kilns and lightweight aggregate kilns that burn hazardous wastes. These emission standards created a technology-based national cap for hazardous air pollutant emissions, assuring that combustion of hazardous waste in these devices is properly controlled. Additionally, the rule satisfied our obligation under the Resource Conservation and Recovery Act (RCRA) to ensure that hazardous waste combustion is conducted in a manner protective of human health and the environment. By using both CAA and RCRA authorities in a coordinated fashion, we consolidated regulatory control of hazardous waste combustion into a single set of regulations, thereby minimizing the potential for conflicting or duplicative federal requirements.

A number of parties, representing interests of both industrial sources and of the environmental community, sought judicial review of the rule. On July 24, 2001, the United States Court of Appeals for the District of Columbia Circuit (the Court) granted the Sierra Club's petition for review and vacated the challenged portions of the rule. However, the Court invited us (or any of the parties to the proceeding) to file a motion to delay issuance of its mandate to request either that the current Phase I standards remain in place or that we be allowed reasonable time to develop interim standards.

On October 19, 2001, after several months of negotiation, we, together with all other petitioners that challenged the hazardous waste combustor emission standards, filed a joint motion asking the Court to stay the issuance of its mandate for four months to allow us time to develop interim standards, and the Court granted this request. In the joint motion, we agreed to take several actions. First, we agreed to issue a one-year extension to the compliance date of September 30, 2002; on December 6, 2001 we published a final rule to extend for one year the compliance date for Phase I sources (66 FR 63313). Second, we committed to (1) publish an interim rule with revised emission standards; and, (2) finalize several compliance and implementation amendments to the rule. These interim standards and compliance and implementation amendments were promulgated on February 13 and 14, 2002 (67 FR 6792 and 67 FR 6968). The interim standards replace the vacated standards temporarily, until we finalize replacement standards that comply with the Court's mandate. Finally, we agreed to issue these final replacement standards that fully comply with the Court's opinion by June 14, 2005.

Also, in this rulemaking, we are developing MACT standards for hazardous waste burning industrial and institutional/commercial boilers, process heaters, and hydrochloric acid production furnaces producing acid from hazardous wastes. These sources are referred to as Phase II sources because the MACT standards for these sources were originally scheduled to be promulgated after the Phase I source MACT standards were finalized.

V. What Data Are Included in This Notice?

We are requesting comment on six separate data bases that compile information on the following source categories or subcategories: incinerators, cement kilns, lightweight aggregate kilns, coal-fired boilers, liquid-fuel boilers, and hydrochloric acid production furnaces. Each data base summarizes emissions data and ancillary information on HWCs source category or subcategory that we extracted from available test reports. Many of the source test reports were prepared as part of the compliance process for the current RCRA standards. Ancillary information in the data bases includes general facility information, air pollution control device operating information, composition and feedrate data for the hazardous waste, fossil fuels, and raw materials, combustion gas condition, and stack-related information.

This NODA is an invitation to comment on the data bases that we will use to develop MACT standards for HWCs. As discussed below, some of the data bases have been noticed, in part, for comment previously, and some have been updated since they were last publicly available. We encourage owners and operators of HWCs to review our data bases to ensure that they are as accurate and complete as possible, and to provide corrections and additions in the form of comments to this notice. If you find errors, please submit the pages from the test report that document the missing or incorrect results and the cover page of the test report as reference. We encourage comment only on the accuracy and completeness of the data bases at this time. We do not seek nor will we use or respond to comments on how to use the data bases to identify MACT standards. Rather, we will publish and seek comment on a MACT standard-setting approach and all other aspects of the NESHAP rulemaking in a future notice of proposed rulemaking.

We gathered the emissions data and ancillary information for the data bases from test reports submitted by these sources to EPA Regional Offices or State agencies. The test reports may include certifications of compliance reports, trial burn reports, annual performance test reports, mini-burns, and risk burn reports. Below we summarize our efforts to collect the test results that comprise the data bases.

We first compiled a data base for hazardous waste burning incinerators, cement kilns and lightweight aggregate kilns (i.e., the Phase I data base) to support the April 1996 proposed Maximum Achievable Control Technology (MACT) standards for those source categories (61 FR 17358, April 19, 1996). We received additional test reports and comments on errors in the data base during the public comment period of the proposed rule. The revised Phase I data base was subsequently published in the Federal Register for public comment (62 FR 960, January 7, 1997). The data base was again revised based on these comments. We used this data base to develop the Phase I MACT standards promulgated on September 30, 1999 (64 FR 52828).

Following vacature of the challenged Phase I standards and promulgation of the interim MACT standards in February 2002, we initiated an effort with EPA Regional Offices and State agencies to update the data base. We focused on collecting compliance testing documents from Phase I sources for which we had no information, obtaining results from more recent testing conducted since 1997, and updating the universe of operating hazardous waste combustors. In total, we obtained an additional 110 test reports during our 2002 data collection effort.

The current data bases for the Phase I source categories included in today's NODA contain test results for over 100 incinerators, 25 cement kilns, and 9 lightweight aggregate kilns. In many cases, especially for cement and lightweight aggregate kilns, the data bases contain test reports from multiple testing campaigns. For example, our data bases contain test results for a cement kiln source for the years 1992, 1995, and 1998.

The data base for Phase II combustors—industrial boilers, commercial/institutional boilers, process heaters, and HCl production furnaces—was compiled in 1999. In developing that data base, we collected the most recent test report available for each source that included test results under compliance test operating conditions. However, this most recent test report may have also included data used for other purposes (e.g., risk burn), which we also included in the data base. In nearly all instances, the dates of the test reports collected were either 1998 or 1999. In June 2000 we published in the Federal Register the Phase II data base for comment (65 FR 39581, June 27, 2000).

We have not collected additional emissions data for Phase II sources. We have, however, updated the Phase II data base to address comments we received to the June 27, 2000 NODA. We also revised the universe of sources by removing those sources that are no longer burning hazardous waste. In addition, we updated some of the comment fields. Therefore, if your facility has a HWC originally included in the Phase II rulemaking, it is important that you review the current data for your facility, even if you reviewed the Phase II data base when it was originally noticed.^[1] Section VII of today's notice describes the new data comment fields for the Phase II sources. The data bases for the Phase II sources comprise compliance test results for 114 industrial boilers, 11 process heaters, and 16 HC1 production furnaces.^[2]

VI. What Data Handling Decisions Did We Make and What Are the Data Gaps?

In this section, we describe the data handling protocol used during development of the data bases. We also identify additional information that we would like to have and encourage owners and operators to submit such information as available.

A. Data from Sources No Longer Burning Hazardous Waste Are Excluded

The data bases do not include information from sources no longer burning hazardous waste. If we learned that a source had stopped burning hazardous waste and is undergoing, or has indicated to regulatory officials its plan to begin, RCRA closure procedures, then we did not obtain a copy of that source's test report. Although such data may or may not indicate the capabilities of control equipment in general, we conclude that the data from currently operating combustors are adequate to develop standards under Section 112(d).

We identified several sources that are no longer burning hazardous waste and removed their emissions data and related information from the data bases. We encourage owners and operators of hazardous waste combustors to review our list of operating combustors to ensure it is accurate.

B. How Are Nondetect Data Handled?

We assume that analytes in feedstreams or emissions reported as not detected are present at one-half the detection limit. This is consistent with how we handled nondetect measurements in the September 1999 MACT rule for Phase I sources (66 FR at 52844) and in the data base associated with the June 2000 NODA for Phase II sources. All measurements reported as not detected are identified as such in the data bases.

C. Missing Source Description Information

Some test reports omitted source description information. For example, some of the boiler descriptions are incomplete. A report might simply say the source is a boiler, but not whether it is a watertube or firetube boiler. In other cases, we were unable to determine what emission control equipment, if any, is installed on the source. Because we may use these data to classify and group the data when identifying MACT standards, we encourage owners and operators to provide any such missing source description information as a comment to this notice.

D. Use of Metals Extrapolation, Interpolation and Surrogates

In some cases, extrapolation or interpolation of metals test data may have been used to develop operating limits (e.g., metals feed rate limits). Extrapolation means setting limits outside the bounds (above or below) of test results, and interpolation means setting operating limits between the bounds of the test results. As we discuss in Section VII below, we need to know whether the emissions data and feedrates represent a snapshot of normal emissions or whether they represent the highest emissions the source has determined it would emit under a mode of operation. Given that subsequent extrapolation and interpolation of the metals data in the test reports may change the classification of the metals data in the data bases, we encourage owners and operators to identify and provide information on test results in the data bases that have been extrapolated and interpolated.

Another situation that may impact the classification of the metals data is the use of surrogates. For example, a source may have spiked lead, but not cadmium, during the test with the intent to use the system removal efficiency of lead to calculate a feedrate limit for cadmium. In this case, our data bases may not classify properly the feedrate of cadmium. We encourage owners and operators to identify and provide information on test results where metal surrogates were used.

VII. What Are the New Data Comment Fields?

We have added several data comment fields to the data bases since they were published for public comment. Because we may use these data comment fields to classify and group the data when establishing the MACT standards, we encourage owners or operators to review these data comment fields to determine if our designations are accurate.

The new data comment fields that are particularly important pertain to: (1) Classification of the design or operation of the source to enable us to consider establishing MACT standards for subcategories of a source category; (2) classification of emissions data as to whether the data represent the highest emissions a source could be expected to achieve or normal emissions; and (3) characterization of sootblowing operations during emissions testing for boilers.^[3]

A. What Information Do We Need to Consider Subcategorization Options?

It may be appropriate to establish different MACT standards for subcategories of a source category if the types or concentration of uncontrolled emissions of hazardous air pollutants are significantly different for a subset of that category because of the design or operation of the sources. An example is our determination that incinerators with wet emission control devices and equipped with waste heat recovery boilers can have much higher D/F emissions than incinerators with wet emission control devices but without heat recovery boilers.^[4]

We have evaluated each of the source categories—hazardous waste burning incinerators, cement kilns, lightweight aggregate kilns, boilers, and HCl production furnaces—and identified information that we may need to classify each source to consider subcategorization. In the table below, we list the classifications and describe the terms for purposes of this rulemaking effort. We encourage owners and operators to review the classifications for their sources in the data bases to ensure they are accurate.

Table 1.—Classification of Sources To Consider Subcategories

Source category/classification	Description
Incinerators:
Waste heat boiler	Equipped with a waste heat recovery boiler.
Liquid injection incinerator	Feeds only pumpable feedstreams that are atomized into the combustion chamber through the burner nozzles.
Mixed waste incinerator	Feeds low level radioactive waste.
Dry APCD	Equipped with a dry emissions control device (e.g., ESP or BH) as the initial control device.
Cement kilns:
Short kiln	Equipped with a precalciner, in-line raw mill, and by-pass duct.
Boilers:
Pulverized coal-fired	Burns pulverized coal in suspension.
Stoker coal-fired	Burns lump coal on a grate.
Liquid fuel boiler	Burns liquid (i.e., pumpable and atomized) or liquid and gaseous fuels only.
HCl production furnaces:
Waste heat boiler	Equipped with a waste heat recovery boiler.

B. How Will We Distinguish Between Worst-Case and Normal Emissions?^[5]

The data bases comprise emissions data from tests conducted for various purposes, including compliance testing (i.e., RCRA trial burns or Certification of Compliance tests), risk burns (i.e., emissions testing to generate emissions data to perform site-specific risk assessments), annual performance testing, and research testing. Therefore, some emissions data represent the highest emissions the source is allowed to emit (i.e., worst-case emissions), some data represent normal operating conditions and emissions, and some data represent operating conditions that are neither normal nor worst case, i.e., they represent operating conditions (and emissions) that are in between normal and worst case. We may choose to consider whether the emissions data are “worst-case” or “normal” to consider emissions variability appropriately in establishing achievable MACT floor ^[6] emission levels. The methodology that we use to establish the MACT floor emission levels may well be influenced by the nature of the emissions data that are used. For example, we may choose to estimate or account for variability in different ways depending on whether the data set we use contains worst-case emission data, data within the range of normal emissions, or a mix of normal and worst case emissions.

Hazardous waste combustors generally emit worst-case emissions during RCRA compliance testing while demonstrating compliance with emission standards. For real-time compliance assurance, sources are required to establish limits on particular operating parameters where the limits are derived from operations during compliance testing. Thus, the emission levels achieved during these compliance tests are the highest emission levels a source is allowed to emit. To ensure that these operating limits do not impede normal operations, sources generally take measures to operate during compliance testing under conditions that are worse than the range of normal operations. For example, sources often feed ash, metals, and chlorine at higher than normal levels (e.g., by spiking the waste feed) to maximize the feedrate, and they often detune the APCDs to minimize collection efficiency. By designing the compliance test to generate emissions higher than the normal range of emissions, sources can establish operating limits that will not impede normal operations while accounting for emissions variability covered by variation in the feedrate of metals or chlorine, for example.

The data bases also include normal emissions data. Sources will sometimes measure emissions of a pollutant during a compliance test even though the test is not designed to establish operating limits for that pollutant (i.e., it is not a compliance test for the pollutant). An example is a trial burn where a lightweight aggregate kiln measures emissions of all RCRA metals, but uses the Tier I metals feedrate limit (rather than the Tier III emissions limit) to comply with the Hg emission standard. Other examples of emissions data that are within the range of normal emissions are annual performance tests that some sources are required to conduct under State regulations, or risk burns. Both of these types of tests are generally performed under normal operating conditions.

Other emissions tests may generate emissions in-between normal and worst-case. An example is a compliance test designed to demonstrate compliance with the particulate matter standard where: (1) The APCD is detuned to achieve worst-case emissions; and (2) the source measures Pb and Cd emissions even though it elects to comply with feedrate limits for those metals and, thus, does not spike those metals. We would conclude that Pb and Cd emissions are in between normal and worst-case emissions because, although emissions of the metals are likely to be higher than normal because the APCD is detuned, emissions are not likely to be worst-case because the source did not use the test to demonstrate compliance with emission standards for the metals (and so did not spike the metals).

To identify normal and worst-case emissions data, we classify emissions data for each pollutant (i.e., D/F, Hg, PM, SVM, LVM, and HCl/Cl2) for each test condition as worst-case (WC); ^[7] normal (N); in between (IB); unknown (U); or not applicable (NA).^[8] We encourage owners and operators to review our classification of their data to ensure that we have applied the terms, as we define them, appropriately, to the information provided for each test condition in the various data fields (e.g., APCD; Spiking; Comments; Condition Description, BIF Tier). Please note that these classifications apply on a pollutant-by-pollutant basis. For example, some pollutants measured during a test condition may be classified as representing worst-case emissions for those pollutants, while other pollutants measured during that test condition may be classified as representing normal emissions.

1. How Do We Define Worst-Case Data?

a. Boilers and HCl Production Furnaces. As discussed above, the data bases for boilers and HCl production furnaces are comprised of all test conditions run during the most recent compliance test campaign for which data are available.^[9] For the metals, total chlorine, and particulate matter standards, we define the worst-case test condition for a pollutant as the test condition with the highest emissions of that pollutant meeting any of these criteria: (1) A test condition where the feedrate of the pollutant (i.e., metal, chlorine, or ash) is maximized by spiking or other means (e.g., feeding waste with atypically high concentrations of the pollutant); or (2) a test condition that is used to demonstrate compliance under Tier III of the BIF rule for the pollutant; or (3) a test condition with higher emissions of the pollutant under operating conditions that would not have been classified as worst case as discussed above.^[10] Test conditions meeting the third criterion are classified WC HE (i.e., worst-case, highest emissions) to clarify that the test condition is worst-case because it has the highest emissions for the test campaign even though its operating conditions would not have suggested that emissions would be worst-case.

It may be helpful to present some examples of how the worst-case definition works. If a metal were spiked during a compliance test, but the source complied with the Tier I feedrate limits under the BIF rule for that metal, we nonetheless classified the test condition as worst-case for that metal (if there were no other test conditions with higher emissions). We reasoned that the source was operating under worst-case conditions during the test, but elected to comply with the Tier I feedrate limits because they were less stringent (i.e., higher) than the feedrate levels during the compliance test. As another example, for a few boilers, emissions could be higher during a risk burn (conducted under conditions that appear to represent other than worst case conditions for that pollutant) than a compliance test. In these cases, we assumed the boiler was operating within its operating limits and classified the test condition as worst-case, highest emissions (WC HE) for that pollutant. This approach ensures that we use available emissions data representing the range of performance of the source to identify the MACT floor.

For dioxin/furan emissions, the worst-case classification is related primarily to whether the source uses a wet or no APCD versus a dry APCD. For liquid fuel boilers ^[11] equipped with an electrostatic precipitator (ESP) or baghouse (BH), we define the worst-case test condition as: (1) The test condition where the inlet temperature to the ESP or BH is maximized (e.g., during a worst-case metals emissions test); or (2) a test condition with higher emissions of the pollutant under operating conditions that would not meet the criteria under (1) above. The test condition where gas temperatures are maximized at the inlet to the ESP or BH should represent worst-case D/F emissions because D/F emissions for sources operated under good combustion conditions (e.g., the BIF requirement to operate at carbon monoxide levels below 100 ppmv) are primarily a function of the temperature of the dry particulate matter control device. D/F formation increases exponentially as the gas inlet temperature increases.^[12]

We considered this approach for coal-fired boilers,^[13] but determined that factors other than gas temperature at the inlet to the ESP or BH appear to have the dominant effect on D/F emissions. For example, we have D/F emissions data for two coal-fired boilers, both of which operated the ESP at approximately 500°F. At that temperature, D/F emissions could be expected to be significant if surface-catalyzed formation reactions are the dominant factor affecting emissions. But, D/F emissions from those two boilers were essentially zero—0.00 and 0.04 ng TEQ/dscm. We conclude that there are other, unquantifiable factors that affect D/F emissions from coal-fired boilers. Sulfur is known to inhibit D/F formation, and we suspect that the sulfur in the coal is a major factor affecting D/F emissions.

Given that we cannot objectively identify a worst-case test condition for D/F emissions from coal-fired boilers, we conclude that the worst-case vs normal classification is not applicable and classify the D/F emissions data as NA. For purposes of assessing variability of emissions in identifying a MACT floor level, however, we would consider the data to be snapshots of normal emissions.

We had similar issues when classifying D/F emissions from liquid fuel boilers with wet or no APCDs, and HCl production furnaces, all of which have wet emission control systems. For sources with wet APCDs,^[14] D/F formation in the emission control device is inhibited because the gas is cooled and because particulate matter is continuously flushed from the control device rather than being held on a surface (e.g., of an ESP plate or BH bag) where particle surface reactions can form D/F. Because we cannot objectively define worst-case conditions for D/F formation for liquid fuel boilers with wet or no APCDs, we conclude that the worst-case vs normal classification is not applicable (as designated by NA). As with the coal-fired boiler D/F data, however, we would consider the data to be snapshots of normal emissions for purposes of assessing variability of emissions in identifying a MACT floor level.

b. Incinerators, Cement Kilns, and Lightweight Aggregate Kilns. As discussed above, the data bases for incinerators, cement kilns, and lightweight aggregate kilns are comprised of all available test conditions. The data bases include test conditions from the most recent test campaign as well as older test campaigns. We use the same definition of worst-case test condition as we use for boilers and HCl production furnaces, as we describe below, except that we apply the definition to the test conditions within each test campaign. For example, assume we have data for a source from three test campaigns run over a period of 10 years. We looked at each test campaign individually and identified the worst-case test condition for each pollutant, if any,^[15] for each test campaign.

For the metals, total chlorine, and particulate matter standards, we define the worst-case test condition for a pollutant as the test condition with the highest emissions of that pollutant meeting any of these criteria: (1) A test condition where the feedrate of the pollutant (i.e., metal, chlorine, or ash) is maximized by spiking or other means (e.g., feeding waste with atypically high concentrations of the pollutant) or where the emission control device is detuned; or (2) a test condition that a cement or lightweight aggregate kiln used to demonstrate compliance under Tier III of the BIF rule for the pollutant, or that an incinerator used to comply with Tier III of the risk assessment guidance; ^[16] or (3) a test condition with higher emissions of the pollutant under any operating conditions, provided that another test condition during the test campaign would have met the worst-case definition under (1) or (2) above.^[17] As discussed for boilers and HCl production furnaces, test conditions meeting the third criterion are classified WC-HE (i.e., worst-case, highest emissions) to clarify that the test condition is worst-case because it has the highest emissions for the test campaign even though its operating conditions would not have suggested that emissions would be worst-case.

For the D/F standards, we use the same classifications that we used for liquid fuel boilers. For incinerators with wet control systems, a worst-case versus normal classification of D/F emissions is not applicable. For incinerators and kilns equipped with an ESP or BH, we define the worst-case test condition as: (1) The test condition where the inlet temperature to the ESP or BH is maximized (e.g., during a worst-case metals emissions test); or (2) a test condition with higher emissions of the pollutant under operating conditions that would not meet the criteria under (1) above.

2. How Do We Define the Normal, In Between, Unknown, and Not Applicable Classifications? ^[18]

We classify emissions data as normal for a pollutant if the available information indicates that the test was run under operating conditions that would reflect normal operations. For example, we classify risk burns (i.e., emissions testing to generate emissions data to perform site-specific risk assessments) as normal for all pollutants when available information indicates the operating conditions were normal.

We classified a test condition as “in between” (IB) for a pollutant if the test condition was a compliance test (i.e., trial burn or certification of compliance test) for the pollutant but there was another test condition (i.e., WC or WC HE) with higher emissions.

We classified a test condition as “unknown” (U) if available information was incomplete to classify the test condition. For each “unknown” classification, we indicate the information we need to classify the test condition. We encourage owners and operators to provide the information and supporting documentation.

We discuss above how we applied the “not applicable” (NA) classification to D/F data for sources equipped with a wet or no APCD and D/F data for coal-fired boilers. We also applied the NA classification to the following situations:

(1) Tests conducted prior to modifications to the APCD, because emissions data prior to an APCS retrofit may not be representative of current operations;

(2) Miniburns, research tests, demonstration tests, because these types of tests are generally used to determine emissions under modes of operation that may not be representative of normal or worst-case operations;

(3) Baseline tests, because emissions when not burning hazardous waste are not relevant to establishing a MACT standard for hazardous waste combustors;

(4) Tests where not all metals in the SVM or LVM group were measured, because SVM and LVM emissions cannot be classified as worst-case or normal if emissions data are not available from the test for both lead and cadmium for SVM, and for arsenic, beryllium, and chromium for LVM; ^[19] and

(5) Tests where a PM run exceeding the RCRA emission standard, because, if a PM run failed the 0.08 gr/dscf RCRA standard, the test failed to demonstrate compliance with the RCRA standards and the test could not be used to establish operating limits.

C. What Classifications Do We Use to Address Sootblowing by Boilers?

Some boilers blow soot periodically to clean the steam tubes to improve the energy efficiency of the boiler. During sootblowing, emissions of PM and metals can increase substantially. To account for the impact of sootblowing on average emissions during RCRA compliance testing, we advised owners and operators to blow soot during one of the three test runs whereby the potential buildup of metals and PM would reflect the buildup over a normal operating cycle.^[20] We also provided a formula for calculating average emissions accounting for the frequency and duration of sootblowing operations.

Some boilers did not blow soot during testing, some were silent on whether they blew soot, some blew soot and used the averaging formula, and some blew soot and calculated average emissions as the arithmetic average of the three test runs. So that we can understand how each source handled sootblowing and determine how best to account for sootblowing in developing the MACT standards, we encourage owners and operators to review the sootblowing classification we assign to their source to determine if it is accurate. We have added a sootblowing status data field to the data base that indicates: (1) The sootblowing run (i.e., R1, R2, or R3); or (2) “No”, indicating the boiler does not blow soot during normal operations; or (3) “U” (i.e., unknown), indicating that we do not know whether the boiler blows soot during normal operations or whether the boiler blew soot during testing, and, if so, during which run. For test conditions classified “U”, we encourage owners and operators to clarify whether the boiler blows soot during normal operations, and whether the boiler blew soot during the test condition (and, if so, during which run).

Dated: June 20, 2002.

Elizabeth A. Cotsworth,

Director, Office of Solid Waste.

Footnotes

1.  See “Hazardous Waste Combustor Data Base Report for Phase I and II Sources,” June, 2002, for our response to comments received on the June 27, 2002 NODA.

2.  We are not aware of any commercial/institutional boilers that burn hazardous waste.

3.  Unless specified otherwise, the term “boiler” means industrial and commercial/institutional boilers, and process heaters.

4.  See USEPA “Final Technical Support Document for HWC MACT Standards, vol. III: Selection of MACT Standards and Technologies,” July, 1999, p. 3-3.

5.  Please note that we did not conduct a worst-case versus normal analysis for DRE or CO/HC data. Under current RCRA regulations, all sources are required to operate under good combustion conditions by complying with emission limits on CO/HC. All sources are also required to comply with operating limits that ensure compliance with a 99.99% DRE requirement. We do not believe that emissions of organic HAPs will be lowered significantly by operating at lower CO/HC levels or higher DRE levels.

6.  The term “floor” refer to the minimum emission standard required pursuant to section 112 of the CAA.

7.  The worst-case (WC) classification is further qualified for some test conditions as “worst-case, highest emissions” (WC HE), as discussed in the text.

8.  NA means the Normal Vs Wors-Case classification is not applicable.

9.  Although we intended to collect test reports from the most recent compliance test campaign, we conclude that for some sources the most recent test reports are for other than compliance tests. For example, for some sources, we apparently have emissions data only for a risk burn representing normal emissions, rather than worst-case emissions under a compliance test.

10.  For PM, the definition of worst-case is more inclusive. If the test report for one or more test conditions in a test campaign indicates that the test is a trial burn or certification of compliance test, we assume that one test condition represents worse-case PM emissions (unless the test report explicitly states otherwise) even if the test report(s) does not explicitly indicate that ask was spiked during the test. This interpretation is appropriate because a source must document compliance with the PM standard by emissions testing. Sources do not have the option of complying with an ash feedrate option (such as the Tier 1 feedrate limits for metals and chlorine) in lie of emissions testing. Consequently, we presume the PM emissions were maximized during one of the compliance tests (e.g., by detuning the APCD; feeding high ash content wastes) event though ask spiking may not be specified.

11.  That is, boilers that burn liquid or liquid and gaseous fuels only.

12.  See USEPA. “Final Technical Support Document for HWC MACT Standards, Volume III: Selection of MACT Standards and Technologies,” July 1999, Chapter 3.

13.  Coal-fired boilers are boilers that burn hazardous waste as a supplemented fuel with coal.

14.  An emission control system comprised of an initial wet control device followed by an ESP or BH would qualify as a wet system. The initial wet device would quench the gas temperature to minimize D/F formation. Conversely, an emission control system comprised of an initial dry control device followed by a wet device (e.g., for HCI control) would not be classified as a wet APCD for purposes of this subcategorization. D/F may be formed in the dry control device before the temperature of the gas is quenched in the wet device below the optimum range for D/F formation.

15.  If a test campaign were comprised of two risk burn test conditions, neither of the test conditions may meet the definition of worst-case.

16.  USEPA, “Guidance on Metals and Hydrogen Chloride Controls for Hazardous Waste Incinerators,” December 29, 1988 (Volume IV of the Hazardous Waste Incineration Guidance Series).

17.  This proviso simply precludes classifying as worst-case the highest normal test condition in a test campaign comprised of only ormal test conditions.

18.  Please note,a s discussed above, the Normal and In Between classifications can be trumped by the “worst-case highest emissions: (WC HE) classification, if in fact, emissions during these test conditions are higher than emissions during a test condition that would otherwise be classified as worst-case.

19.  Plase note that, for some source categories where there are substantial emissions data for only lead or only chromium during a test condition, we classified the lead-only or chromium-only data by worse-case vs normal. In addition, we did not apply the NA classification to LVM emissions data if only beryllium emissions data were missing. This is because beryllium emissions are virtually always substantially lower than either arsenic or chromium emissions, and thus, do not contribute substantially to LVM emissions.

20.  See USEP, “Technical Implementation Document for EPA's Boiler and Industrial Furnance Regulations,” March 1992, p. 5-14.