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January 14, 2003 Part II Environmental Protection Agency 40 CFR Part 63 National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines; Proposed Rule VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00001 Fmt 4717 Sfmt 4717 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1888 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 63 [ OAR   2002   0060; FRL   7417   8]

RIN 2060   AG67 National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines AGENCY: Environmental Protection Agency ( EPA). ACTION: Proposed rule.

SUMMARY: This action proposes national emission standards for hazardous air pollutants ( NESHAP) for stationary combustion turbines. We have identified stationary combustion turbines as major sources of hazardous air pollutants ( HAP) emissions such as formaldehyde, toluene, benzene, and acetaldehyde. The proposed NESHAP would implement section 112( d) of the Clean Air Act ( CAA) by requiring all major sources to meet HAP emission standards reflecting the application of the maximum achievable control technology ( MACT) for combustion turbines. We estimate that 20 percent of the stationary combustion turbines affected by the proposed rule will be located at major sources. As a result, the environmental, energy, and economic impacts presented in this preamble reflect these estimates. The proposed standards would protect public health by reducing exposure to air pollution, by reducing total national HAP emissions by an estimated 81 tons/ year in the 5th year after the standards are promulgated. This action also proposes to add Method 323 of 40 CFR part 63, appendix A for the measurement of formaldehyde emissions from natural gas fired stationary sources. DATES: Comments. Submit comments on or before February 13, 2003. Public Hearing. If anyone contacts us requesting to speak at a public hearing by January 24, 2003, we will hold a public hearing on January 29, 2003. ADDRESSES: Comments may be submitted by mail ( in duplicate, if possible) to EPA West ( Air Docket), U. S. EPA ( MD   6102T), Room B   108, 1200 Pennsylvania Avenue, NW., Washington, DC 20460, Attention Docket ID No. OAR   2002   0060. By hand delivery/ courier, comments may be submitted ( in duplicate, if possible) to EPA Docket Center ( Air Docket), U. S. EPA, MD   6102T), Room B   108, 1301 Constitution Avenue, NW., Washington, DC 20460, Attention Docket ID No. OAR   2002   0060. Comments may be submitted electronically according to the detailed instructions as provided in the SUPPLEMENTARY INFORMATION section. Public Hearing. If a public hearing is held, it will be held at the new EPA facility complex in Research Triangle Park, North Carolina. Docket. Docket No. OAR   2002   0060 contains supporting information used in developing the standards. The docket is located at the U. S. EPA, 1301 Constitution Avenue, NW., Washington, DC 20460 in room B102, and may be inspected from 8: 30 a. m. to 4: 30 p. m., Monday through Friday, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: Mr. Sims Roy, Combustion Group, Emission Standards Division ( MD   C439   01), U. S. EPA, Research Triangle Park, North Carolina 27711; telephone number ( 919) 541   5263; facsimile number ( 919) 541   5450; electronic mail address roy. sims@ epa. gov.

SUPPLEMENTARY INFORMATION: Regulated Entities. Categories and entities potentially regulated by this action include:

Category SIC NAICS Examples of regulated entities Any industry using a stationary combustion turbine as defined in the regulation. 4911 2211 Electric power generation, transmission, or distribution 4922 486210 Natural gas transmission. 1311 211111 Crude petroleum and natural gas production. 1321 211112 Natural gas liquids producers. 4931 221 Electric and other services combined.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. To determine whether your facility is regulated by this action, you should examine the applicability criteria in § 63.6085 of the proposed rule. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed in the preceding FOR FURTHER INFORMATION CONTACT section. Docket. The EPA has established an official public docket for this action under Docket ID No. OAR   2002   0060. 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 Air and Radiation Docket in the EPA Docket Center, ( EPA/ DC) EPA West, Room B108, 1301 Constitution Ave., NW., Washington, DC. The EPA Docket Center Public Reading Room is open from 8: 30 a. m. to 4: 30 p. m., Monday through Friday, excluding legal holidays. The telephone number for the Reading Room is ( 202) 566   1744, and the telephone number for the Air and Radiation Docket is ( 202) 566   1742. A reasonable fee may be charged for copying docket materials. 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. The 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 VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00002 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1889 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules 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 above. The 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 on 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. You may submit comments electronically, by mail, 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.'' The EPA is not required to consider these late comments. However, late comments may be considered if time permits. Electronically. 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. The 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. 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. OAR   2002   0060. 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. Comments may be sent by electronic mail ( e mail) to a and r docket@ epa. gov, Attention Docket ID No. OAR   2002   0060. 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 email 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. You may submit comments on a disk or CD ROM that you mail to the mailing address identified below. These electronic submissions will be accepted in WordPerfect or ASCII file format. Avoid the use of special characters and any form of encryption. By Mail. Send your comments ( in duplicate if possible) to: Air and Radiation Docket and Information Center, U. S. EPA, Mailcode: 6102T, 1200 Pennsylvania Ave., NW, Washington, DC, 20460, Attention Docket ID No. OAR   2002   0060. The EPA requests a separate copy also be sent to the contact person listed above ( see FOR FURTHER INFORMATION CONTACT). By Hand Delivery or Courier. Deliver your comments to: EPA Docket Center, Room B108, 1301 Constitution Ave., NW, Washington, DC, 20460, Attention Docket ID No. OAR   2002   0060. Such deliveries are only accepted during the Docket's normal hours of operation as identified above. 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: Mr. Sims Roy, c/ o OAQPS Document Control Officer ( Room C404   2), U. S. EPA, Research Triangle Park, 27711, Attention Docket ID No. OAR   2002   0060. 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 CDROM 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. 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.

VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00003 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1890 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules 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. Public Hearing. Persons interested in presenting oral testimony or inquiring as to whether a hearing is to be held should contact Mrs. Kelly Hayes, Combustion Group, Emission Standards Division ( MD   C439   01), U. S. EPA, Research Triangle Park, North Carolina 27711, ( 919) 541   5578 at least 2 days in advance of the public hearing. Persons interested in attending the public hearing must also call Mrs. Hayes to verify the time, date, and location of the hearing. The public hearing will provide interested parties the opportunity to present data, views, or arguments concerning the proposed rule. If a public hearing is requested and held, EPA will ask clarifying questions during the oral presentation but will not respond to the presentations or comments. Written statements and supporting information will be considered with equivalent weight as any oral statement and supporting information presented at a public hearing, if held. Outline. The information presented in this preamble is organized as follows:

I. Background A. What is the regulatory development background of the source category? B. What is the source of authority for development of NESHAP? C. What criteria are used in the development of NESHAP? D. What are the health effects associated with HAP from stationary combustion turbines? II. Summary of the Proposed Rule A. Am I subject to the proposed rule? B. What source categories and subcategories are affected by the proposed rule? C. What are the primary sources of HAP emissions and what are the emissions? D. What are the emission limitations and operating limitations? E. What are the initial compliance requirements? F. What are the continuous compliance provisions? G. What monitoring and testing methods are available to measure these low concentrations of CO and formaldehyde? H. What are the notification, recordkeeping and reporting requirements? III. Rationale for Selecting the Proposed Standards A. How did we select the source category and any subcategories? B. What about stationary combustion turbines located at area sources? C. What is the affected source? D. How did we determine the basis and level of the proposed emission limitations for existing sources? E. How did we determine the basis and level of the proposed emission limitations and operating limitations for new sources? F. How did we select the format of the standard for new diffusion flame combustion turbines? G. How did we select the initial compliance requirements? H. How did we select the continuous compliance requirements? I. How did we select the monitoring and testing methods to measure these low concentrations of CO and formaldehyde? J. How did we select the notification, recordkeeping and reporting requirements? IV. Summary of Environmental, Energy and Economic Impacts A. What are the air quality impacts? B. What are the cost impacts? C. What are the economic impacts? D. What are the nonair health, environmental and energy impacts? V. Solicitation of Comments and Public Participation A. General B. Can we achieve the goals of the proposed rule in a less costly manner? C. Limited Use Subcategory VI. Administrative Requirements A. Executive Order 12866, Regulatory Planning and Review B. Executive Order 13132, Federalism C. Executive Order 13175, Consultation and Coordination with Indian Tribal Governments D. Executive Order 13045, Protection of Children from Environmental Health Risks and Safety Risks E. Executive Order 13211, Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use F. Unfunded Mandates Reform Act of 1995 G. Regulatory Flexibility Act ( RFA), as Amended by the Small Business Regulatory Enforcement Fairness Act of 1996 ( SBREFA), 5 U. S. C. 601 et seq. H. Paperwork Reduction Act I. National Technology Transfer and Advancement Act I. Background A. What Is the Regulatory Development Background of the Source Category? In September 1996, we chartered the Industrial Combustion Coordinated Rulemaking ( ICCR) advisory committee under the Federal Advisory Committee Act ( FACA). The committee's objective was to develop recommendations for regulations for several combustion source categories under sections 112 and 129 of the CAA. The ICCR advisory committee, also known as the Coordinating Committee, formed Source Work Groups for the various combustor types covered under the ICCR. One work group, the Combustion Turbine Work Group, was formed to research issues related to stationary combustion turbines. The Combustion Turbine Work Group submitted recommendations, information, and data analyses to the Coordinating Committee, which in turn considered them and submitted recommendations and information to us. The Committee's 2 year charter expired in September 1998. We considered the Committee's recommendations in developing the proposed rule for stationary combustion turbines.

B. What Is the Source of Authority for Development of NESHAP? Section 112 of the CAA requires us to list categories and subcategories of major sources and area sources of HAP and to establish NESHAP for the listed source categories and subcategories. The stationary turbine source category was listed on July 16, 1992 ( 57 FR 31576). Major sources of HAP are those that have the potential to emit greater than 10 ton/ yr of any one HAP or 25 ton/ yr of any combination of HAP.

C. What Criteria Are Used in the Development of NESHAP? Section 112 of the CAA requires that we establish NESHAP for the control of HAP from both new and existing major sources. The CAA requires the NESHAP to reflect the maximum degree of reduction in emissions of HAP that is achievable. This level of control is commonly referred to as the MACT. The MACT floor is the minimum control level allowed for NESHAP and is defined under section 112( d)( 3) of the CAA. In essence, the MACT floor ensures that the standard is set at a level that assures that all major sources achieve the level of control at least as stringent as that already achieved by the better controlled and lower emitting sources in each source category or subcategory. For new sources, the MACT standards cannot be less stringent than the emission control that is achieved in practice by the best controlled similar source. The MACT standards for existing sources can be less stringent than standards for new sources, but they cannot be less stringent than the average emission limitation achieved by the best performing 12 percent of existing sources in the category or subcategory ( or the best performing 5 sources for categories or subcategories with fewer than 30 sources). In developing MACT, we also consider control options that are more stringent than the floor. We may establish standards more stringent than the floor based on the consideration of cost of achieving the emissions VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00004 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1891 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules reductions, any nonair quality health and environmental impacts, and energy requirements.

D. What Are the Health Effects Associated With HAP From Stationary Combustion Turbines?

Emission data collected during development of the proposed NESHAP show that several HAP are emitted from stationary combustion turbines. These HAP emissions are formed during combustion or result from HAP compounds contained in the fuel burned. Among the HAP which have been measured in emission tests that were conducted at natural gas fired and distillate oil fired combustion turbines are: 1,3 butadiene, acetaldehyde, acrolein, benzene, ethylbenzene, formaldehyde, naphthalene, poly aromatic hydrocarbons ( PAH) propylene oxide, toluene, and xylenes. Metallic HAP from distillate oil fired stationary combustion turbines that have been measured are: arsenic, beryllium, cadmium, chromium, lead, manganese, mercury, nickel, and selenium. Although numerous HAP may be emitted from combustion turbines, only a few account for essentially all the mass of HAP emissions from stationary combustion turbines. These HAP are: formaldehyde, toluene, benzene, and acetaldehyde. The HAP emitted in the largest quantity is formaldehyde. Formaldehyde is a probable human carcinogen and can cause irritation of the eyes and respiratory tract, coughing, dry throat, tightening of the chest, headache, and heart palpitations. Acute inhalation has caused bronchitis, pulmonary edema, pneumonitis, pneumonia, and death due to respiratory failure. Long term exposure can cause dermatitis and sensitization of the skin and respiratory tract. Other HAP emitted in significant quantities from stationary combustion turbines include toluene, benzene, and acetaldehyde. The health effect of primary concern for toluene is dysfunction of the central nervous system ( CNS). Toluene vapor also causes narcosis. Controlled exposure of human subjects produced mild fatigue, weakness, confusion, lacrimation, and paresthesia; at higher exposure levels there were also euphoria, headache, dizziness, dilated pupils, and nausea. After effects included nervousness, muscular fatigue, and insomnia persisting for several days. Acute exposure may cause irritation of the eyes, respiratory tract, and skin. It may also cause fatigue, weakness, confusion, headache, and drowsiness. Very high concentrations may cause unconsciousness and death. Benzene is a known human carcinogen. The health effects of benzene include nerve inflammation, CNS depression, and cardiac sensitization. Chronic exposure to benzene can cause fatigue, nervousness, irritability, blurred vision, and labored breathing and has produced anorexia and irreversible injury to the bloodforming organs; effects include aplastic anemia and leukemia. Acute exposure can cause dizziness, euphoria, giddiness, headache, nausea, staggering gait, weakness, drowsiness, respiratory irritation, pulmonary edema, pneumonia, gastrointestinal irritation, convulsions, and paralysis. Benzene can also cause irritation to the skin, eyes, and mucous membranes. Acetaldehyde is a probable human carcinogen. The health effects for acetaldehyde are irritation of the eyes, mucous membranes, skin, and upper respiratory tract, and it is a CNS depressant in humans. Chronic exposure can cause conjunctivitis, coughing, difficult breathing, and dermatitis. Chronic exposure may cause heart and kidney damage, embryotoxicity, and teratogenic effects. Acetaldehyde is a potential carcinogen in humans.

II. Summary of the Proposed Rule A. Am I Subject to the Proposed Rule?

The proposed rule applies to you if you own or operate a stationary combustion turbine which is located at a major source of HAP emissions. A major source of HAP emissions is a plant site that emits or has the potential to emit any single HAP at a rate of 10 tons ( 9.07 megagrams) or more per year or any combination of HAP at a rate of 25 tons ( 22.68 megagrams) or more per year. Section 112( n)( 4) of the CAA requires that the aggregation of HAP for purposes of determining whether an oil and gas production facility is major or nonmajor be done only with respect to particular sites within the source and not on a total aggregated site basis. We incorporated the requirements of section 112( n)( 4) of the CAA into our NESHAP for Oil and Natural Gas Production Facilities in subpart HH of part 63. As in subpart HH, we plan to aggregate HAP emissions for the purposes of determining a major HAP source for turbines only with respect to particular sites within an oil and gas production facility. The sites are called surface sites and may include a combination of any of the following equipment; glycol dehydrators, tanks which have potential for flash emissions, reciprocating internal combustion engines and combustion turbines.

Six subcategories have been defined within the stationary combustion turbine source category. While all stationary combustion turbines are subject to the proposed rule, each subcategory has distinct requirements. For example, existing diffusion flame combustion turbines and stationary combustion turbines with a rated peak power output of less than 1.0 megawatt ( MW) ( at International Organization for Standardization ( ISO) standard day conditions) are not required to comply with emission limitations, recordkeeping or reporting requirements in the proposed rule. New or reconstructed stationary combustion turbines and existing lean premix stationary combustion turbines with a rated peak power output of 1.0 MW or more that either operate exclusively as an emergency stationary combustion turbine, as a limited use stationary combustion turbine, or as a stationary combustion turbine which burns landfill gas or digester gas as its primary fuel must only comply with the initial notification requirements. New or reconstructed diffusion flame or lean premix combustion turbines must comply with emission limitations, recordkeeping and reporting requirements in the proposed rule. The emission limitations for each subcategory are summarized in Table 2 of this preamble. You must determine your source's subcategory to determine which requirements apply to your source.

The proposed rule does not apply to stationary combustion turbines located at an area source of HAP emissions. An area source of HAP emissions is a plant site that does not emit any single HAP at a rate of 10 tons ( 9.07 megagrams) or greater per year or any combination of HAP at a rate of 25 tons ( 22.68 megagrams) or greater per year. To determine whether a facility is a major source, EPA will accept HAP emissions estimated using HAP emission factors listed in Table 1 of this preamble.

VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00005 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1892 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules TABLE 1.   SUMMARY OF HAP EMISSION FACTORS Turbine Load Fuel HAP emission factor ( lb/ MMBtu)

Diffusion Flame ........................................................... All loads ......................................... Natural Gas .................................... 0.0188 Diffusion Flame ........................................................... > 80% .............................................. Natural Gas .................................... 0.00479 Diffusion Flame ........................................................... All loads ......................................... Diesel ............................................. 0.00241 Diffusion Flame ........................................................... > 80% .............................................. Diesel ............................................. 0.00233 Lean Premix ............................................................... All loads ......................................... Natural Gas .................................... 0.000644 Lean Premix ............................................................... > 80% .............................................. Natural Gas .................................... 0.000212 If the turbine mainly operates at high load, the emission factor for greater than 80 percent load should be used. If the turbine operates on varying loads, the emission factor for all loads should be used. Emission factors were developed based on data from the combustion turbines emissions database. A copy of the emissions database may be downloaded off the internet at http:// www. epa. gov/ ttn/ atw/ combust/ turbine/ turbpg. html. The proposed rule does not cover duct burners. They are part of the waste heat recovery unit in a combined cycle system. Waste heat recovery units, whether part of a cogeneration system or a combined cycle system, are steam generating units and are not covered by the proposed rule. Finally, the proposed rule does not apply to stationary combustion engine test cells/ stands since these facilities will be covered by another NESHAP, 40 CFR part 63, subpart PPPPP.

B. What Source Categories and Subcategories Are Affected by the Proposed Rule? The proposed rule covers stationary combustion turbines. A stationary combustion turbine is any simple cycle stationary combustion turbine, any regenerative/ recuperative cycle stationary combustion turbine, the combustion turbine portion of any stationary cogeneration cycle combustion system, or the combustion turbine portion of any stationary combined cycle steam/ electric generating system. Stationary means that the combustion turbine is not self propelled or intended to be propelled while performing its function. The combustion turbine may, however, be mounted on a vehicle for portability or transportability. Stationary combustion turbines have been divided into the following six subcategories: ( 1) Emergency stationary combustion turbines, ( 2) limited use stationary combustion turbines, ( 3) stationary combustion turbines which fire landfill gas or digester gas as their primary fuel, ( 4) stationary combustion turbines of less than 1 MW rated peak power output, ( 5) stationary diffusion flame combustion turbines, and ( 6) stationary lean premix combustion turbines. An emergency stationary combustion turbine means any stationary combustion turbine that operates as a mechanical or electrical power source when the primary power source for a facility has been rendered inoperable by an emergency situation. One example is emergency power for critical networks or equipment when electric power from the normal source of power is interrupted. Another example is to pump water in the case of fire or flood. Peaking units at electric utilities and other types of stationary combustion turbines that typically operate at low capacity factors, but are not confined to operation in an emergency, are not emergency stationary combustion turbines. A limited use stationary combustion turbine means any stationary combustion turbine that operates 50 hours or less per calendar year. One example is a stationary combustion turbine used to stabilize electrical power voltage and protect sensitive electronic equipment during periods of brown outs. Another example is periodic operation of an emergency stationary combustion turbine to check readiness or perform maintenance checks. Since electrical power has not been interrupted during these readiness and maintenance checks, the stationary combustion turbine is not operating as an emergency stationary combustion turbine. We are specifically soliciting comments on creating a subcategory of limited use combustion turbines with a capacity utilization of 10 percent or less. This is further discussed in the `` Solicitation of Comments and Public Participation'' section of this preamble. Stationary combustion turbines which fire landfill gas or digester gas as their primary fuel qualify as a separate subcategory because the types of control available for these turbines are limited. Stationary combustion turbines of less than 1 MW rated peak power output were also identified as a subcategory. These small stationary combustion turbines are few in number and, to our knowledge, none use emission control technology to reduce HAP. Given the very small size of these stationary combustion turbines and the lack of application of HAP emission control technologies, we have concerns about the applicability of HAP emission control technology to them. The stationary diffusion flame combustion turbines subcategory includes only diffusion flame combustion turbines that are greater than 1 MW rated peak power output and are not emergency stationary combustion turbines, limited use stationary combustion turbines, or stationary combustion turbines which fire landfill gas or digester gas as their primary fuel. In a diffusion flame combustor, the fuel and air are injected at the combustor and are mixed only by diffusion prior to ignition. Hazardous air pollutants emissions from these turbines can be significantly decreased with the addition of air pollution control equipment. The stationary lean premix combustion turbines subcategory includes only lean premix combustion turbines that are greater than 1 MW rated peak power output and are not emergency stationary combustion turbines, limited use stationary combustion turbines, or stationary combustion turbines which fire landfill gas or digester gas as their primary fuel. Lean premix technology, introduced in the 1990' s, was developed to reduce NOX emissions without the use of add on controls. In a staged lean premix combustor, the air and fuel are thoroughly mixed to form a lean mixture before delivery to the combustor. The staged entry limits the flame temperature and the residence time at the peak flame temperature. Lean premix combustors emit lower levels of NOX, carbon monoxide ( CO), formaldehyde and other HAP than diffusion flame combustion turbines.

VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00006 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1893 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules C. What Are the Primary Sources of HAP Emissions and What Are the Emissions? The sources of emissions are the exhaust gases from combustion of gaseous and liquid fuels in a stationary combustion turbine. Hazardous air pollutants that are present in the exhaust gases from stationary combustion turbines include formaldehyde, toluene, benzene, and acetaldehyde.

D. What Are the Emission Limitations and Operating Limitations? As the owner or operator of an existing lean premix stationary combustion turbine or a new or reconstructed stationary combustion turbine located at a major source of HAP emissions, you must comply with one of the following two emission limitations by the effective date of the standard ( or upon startup if you start up your stationary combustion turbine after the effective date of the standard): ( 1) Reduce CO emissions in the exhaust from the new or reconstructed stationary combustion turbine by 95 percent or more, if you use an oxidation catalyst emission control device; or ( 2) reduce the concentration of formaldehyde in the exhaust from the new or reconstructed stationary combustion turbine to 43 parts per billion by volume or less, dry basis ( ppbvd), at 15 percent oxygen, if you use means other than an oxidation catalyst emission control device. There are no operating limitations if you choose to comply with the emission limitation for CO emission reduction. If you comply with the emission limitation for formaldehyde emissions and your stationary combustion turbine is not lean premix or diffusion flame, you must comply with any additional operating limitations approved by the Administrator, as discussed later. Finally, as mentioned earlier, stationary combustion turbines with a rated peak power output of less than 1.0 MW, emergency stationary combustion turbines, limited use stationary combustion turbines, and stationary combustion turbines which burn landfill gas or digester gas as their primary fuel, are not required to comply with these emission limitations. In addition, existing diffusion flame stationary combustion turbines, are not required to comply with these emission limitations. The emission limitations for each subcategory are summarized in Table 2 of this preamble.

TABLE 2.   SUMMARY OF EMISSION LIMITATIONS Subcategory Emission limitation Comment Existing Diffusion Flame Stationary Combustion Turbine   1.0 MW. None ................................................................................ No requirements.

Existing Lean Premix Stationary Combustion Turbine   1.0 MW. ( 1) Reduce CO emissions by 95% or more, if you use an oxidation catalyst emission control device. or ( 2) Reduce the concentration of formaldehyde to 43 ppbvd @ 15% O2, if you use means other than an oxidation catalyst emission control device. or New/ Reconstructed Stationary Combustion Turbine   1.0 MW. Emergency Stationary Combustion Turbine .................... or No emission limitations .................................................... Initial notification requirements only. Limited Use Stationary Combustion Turbine or Landfill/ Digester Gas Stationary Combustion Turbine.   1 MW Stationary Combustion Turbine .......................... None ................................................................................ No requirements.

E. What Are the Initial Compliance Requirements? The initial compliance requirements for a stationary combustion turbine vary depending on the subcategory of your combustion turbine and your control strategy. If you operate a new or reconstructed stationary combustion turbine and comply with the emission limitation for CO emission reduction, you must install a continuous emission monitoring system ( CEMS) to measure CO and either carbon dioxide or oxygen simultaneously at the inlet and outlet of the oxidation catalyst emission control device. To demonstrate initial compliance, you must conduct an initial performance evaluation using Performance Specifications 3 and 4A of 40 CFR part 60, appendix B. You must demonstrate that the reduction of CO emissions is at least 95 percent using the first 4 hour average after a successful performance evaluation. Your inlet and outlet measurements must be on a dry basis and corrected to 15 percent oxygen or equivalent carbon dioxide content. You must also conduct an annual relative accuracy test audit ( RATA) of the CEMS using Performance Specifications 3 and 4A of 40 CFR part 60, appendix B. If you operate a new or reconstructed combustion turbine or an existing lean premix combustion turbine and comply with the emission limitation for formaldehyde emissions, you must conduct an initial performance test using Test Method 320 of 40 CFR part 63, appendix A; ARB Method 430 of California Environmental Protection Agency, Air Resources Board, 2020 L Street, Sacramento, CA 95812; or EPA Solid Waste ( SW)   846 Method 0011 to demonstrate that the outlet concentration of formaldehyde is 43 ppbvd or less ( corrected to 15 percent oxygen). Natural gas fired sources may also use the proposed Test Method 323 of 40 CFR part 63, appendix A, to measure formaldehyde. To correct to 15 percent oxygen, dry basis, you must measure oxygen using Method 3A or 3B of 40 CFR part 60, appendix A, and moisture using Method 4 of 40 CFR part 60, appendix A. As stated previously, if you choose to comply with the emission limitation for formaldehyde emissions and your stationary combustion turbine is not lean premix or diffusion flame, you must also petition the Administrator for approval of operating limitations or approval of no operating limitations. If you petition the Administrator for approval of operating limitations, your petition must include the following: ( 1) Identification of the specific parameters VerDate Dec< 13> 2002 20: 03 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00007 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1894 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules you propose to use as operating limitations; ( 2) a discussion of the relationship between these parameters and HAP emissions, identifying how HAP emissions change with changes in these parameters and how limitations on these parameters will serve to limit HAP emissions; ( 3) a discussion of how you will establish the upper and/ or lower values for these parameters which will establish the limits on these parameters in the operating limitations; ( 4) a discussion identifying the methods you will use to measure and the instruments you will use to monitor these parameters, as well as the relative accuracy and precision of these methods and instruments; and ( 5) a discussion identifying the frequency and methods for recalibrating the instruments you will use for monitoring these parameters. If you petition the Administrator for approval of no operating limitations, your petition must include the following: ( 1) Identification of the parameters associated with operation of the stationary combustion turbine and any emission control device which could change intentionally ( e. g., operator adjustment, automatic controller adjustment, etc.) or unintentionally ( e. g., wear and tear, error, etc.) on a routine basis or over time; ( 2) a discussion of the relationship, if any, between changes in these parameters and changes in HAP emissions; ( 3) for those parameters with a relationship to HAP emissions, a discussion of whether establishing limitations on these parameters would serve to limit HAP emissions; ( 4) for those parameters with a relationship to HAP emissions, a discussion of how you could establish upper and/ or lower values for these parameters which would establish limits on these parameters in operating limitations; ( 5) for those parameters with a relationship to HAP emissions, a discussion identifying the methods you could use to measure these parameters and the instruments you could use to monitor them, as well as the relative accuracy and precision of these methods and instruments; ( 6) for these parameters, a discussion identifying the frequency and methods for recalibrating the instruments you could use to monitor them; and ( 7) a discussion of why, from your point of view, it is infeasible or unreasonable to adopt these parameters as operating limitations.

F. What Are the Continuous Compliance Provisions? Several general continuous compliance requirements apply to stationary combustion turbines required to comply with the emission limitations. You are required to comply with the emission limitations and the operating limitations ( if applicable) at all times, except during startup, shutdown, and malfunction of your stationary combustion turbine. You must also operate and maintain your stationary combustion turbine, air pollution control equipment, and monitoring equipment according to good air pollution control practices at all times, including startup, shutdown, and malfunction. You must conduct all monitoring at all times that the stationary combustion turbine is operating, except during periods of malfunction of the monitoring equipment or necessary repairs and quality assurance or control activities, such as calibration checks. To demonstrate continuous compliance with the CO emission reduction limitation, you must calibrate and operate your CEMS according to the requirements in 40 CFR 63.8. You must continuously monitor and record the CO concentration before and after the oxidation catalyst emission control device and calculate the percent reduction of CO emissions hourly. The reduction in CO emissions must be 95 percent or more, based on a rolling 4 hour average, averaged every hour. To demonstrate continuous compliance with the operating limitations ( if applicable), you must continuously monitor the values of any parameters which have been approved by the Administrator as operating limitations. The proposed rule does not require your lean premix combustion turbine to demonstrate continuous compliance. It is assumed that if you meet the low NOX emission levels required by your federally enforceable permit ( or guaranteed by the turbine manufacturer if there is no permit level), your turbine is in compliance with the 43 ppbvd formaldehyde emission limit.

G. What Monitoring and Testing Methods Are Available to Measure These Low Concentrations of CO and Formaldehyde? Continuous emissions monitoring systems are available which can accurately measure CO emission reduction at the low concentrations found in the combustion turbine exhaust following an oxidation catalyst emission control device. Our performance specification for CO CEMS ( PS   4A) of 40 CFR part 60, appendix A, however, has not been updated recently and does not reflect the performance capabilities of these systems. We are currently undertaking a review of PS   4A of 40 CFR part 60, appendix A, for CO CEMS and, in conjunction with this effort, we solicit comments on the performance capabilities of CO CEMS and their ability to accurately measure the low concentrations of CO experienced in the exhaust of a combustion turbine following an oxidation catalyst emission control device. Similarly, our Fourier Transform Infrared ( FTIR) test method, Method 320 of 40 CFR part 63, appendix A, as well as EPA SW   846 Method 0011 and CARB Method 430, can be used to accurately measure formaldehyde concentrations in the exhaust of a combustion turbine as low as 43 ppbvd. As these test methods are currently written, however, they do not provide for this level of accuracy. These methods must be used with some revisions to achieve such accuracy. As a result, we are currently undertaking a review of our FTIR method, Method 320 of 40 CFR part 63, appendix A, to incorporate revisions to ensure it can be used to accurately measure formaldehyde concentrations as low as 43 ppbvd in the exhaust from a combustion turbine. In conjunction with this effort, we solicit comments on revisions to Method 320 of 40 CFR part 63, appendix A, to ensure accurate measurement of such low concentrations of formaldehyde. We are also proposing to add Method 323 of 40 CFR part 63, appendix A. Method 323 is for the measurement of formaldehyde emissions from natural gas fired stationary sources using acetyl acetone derivitization. We solicit comments on the use of this method to measure low concentrations of formaldehyde.

H. What Are the Notification, Recordkeeping and Reporting Requirements? You must submit all of the applicable notifications as listed in the NESHAP General Provisions ( 40 CFR part 63, subpart A), including an initial notification, notification of performance test or evaluation, and a notification of compliance, for each stationary combustion turbine which must comply with the emission limitations. If your new or reconstructed source is located at a major source, has greater than 1 MW rated peak power output, and is an emergency stationary combustion turbine, limited use stationary combustion turbine or a combustion turbine which fires landfill or digester gas as its primary fuel, you must submit only an initial notification. For each combustion turbine subject to the emission limitations, you must VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00008 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1895 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules record all of the data necessary to determine if you are in compliance with the emission limitations. Your records must be in a form suitable and readily available for review. You must also keep each record for 5 years following the date of each occurrence, measurement, maintenance, report, or record. Records must remain on site for at least 2 years and then can be maintained off site for the remaining 3 years. You must submit a compliance report semiannually for each new or reconstructed stationary combustion turbine that must comply with the CO emission reduction limitation. This report must contain the company name and address, a statement by a responsible official that the report is accurate, a statement of compliance, or documentation of any deviation from the requirements of the proposed rule during the reporting period.

III. Rationale for Selecting the Proposed Standards A. How Did We Select the Source Category and Any Subcategories?

Stationary combustion turbines can be major sources of HAP emissions and, as a result, we listed them as a major source category for regulatory development under section 112 of the CAA. Section 112 of the CAA allows us to establish subcategories within a source category for the purpose of regulation. Consequently, we evaluated several criteria associated with stationary combustion turbines which might serve as potential subcategories. We identified six subcategories of stationary combustion turbines located at major sources: ( 1) Emergency stationary combustion turbines, ( 2) limited use stationary combustion turbines, ( 3) stationary combustion turbines which fire landfill gas or digester gas as their primary fuel, ( 4) stationary combustion turbines of less than 1 MW rated peak power output, ( 5) stationary diffusion flame combustion turbines, and ( 6) stationary lean premix combustion turbines. Stationary combustion turbines can be classified as either diffusion flame or lean premix. We examined formaldehyde test data for both diffusion flame and lean premix stationary combustion turbines and observed that uncontrolled formaldehyde emissions for stationary lean premix combustion turbines are significantly lower than those of stationary diffusion flame combustion turbines. An analysis of the formaldehyde emissions data shows that uncontrolled formaldehyde emissions from stationary lean premix combustion turbines are comparable to controlled formaldehyde emissions from stationary diffusion flame combustion turbines controlled with oxidation catalyst systems. Due to the difference in the two technologies, we decided to establish subcategories for diffusion flame and lean premix stationary combustion turbines. We identified emergency stationary combustion turbines as a subcategory. Emergency stationary combustion turbines operate only in emergencies, such as a loss of power provided by another source. These types of stationary combustion turbines operate infrequently and, when called upon to operate, must respond without failure and without lengthy periods of startup. These conditions limit the applicability of HAP emission control technology to emergency stationary combustion turbines. Limited use stationary combustion turbines were also identified as a subcategory. These types of stationary combustion turbines are operated 50 hours per calendar year or less. They are used primarily to stabilize electrical power voltage levels during periods of brown outs to prevent damage to sensitive electronic equipment. As with emergency stationary combustion turbines, they are operated infrequently and, when called upon to operate, must respond without failure and without lengthy periods of startup. These conditions limit the applicability of HAP emission control technology. Similarly, stationary combustion turbines which fire landfill gas or digester gas as their primary fuel were identified as a subcategory. Landfill and digester gases contain a family of chemicals referred to as siloxanes, which limit the application of HAP emission control technology. Stationary combustion turbines of less than 1 MW rated peak power output were also identified as a subcategory. We believe these small stationary combustion turbines are few in number and, to our knowledge, none use emission control technology to reduce HAP. Given the very small size of these stationary combustion turbines and the lack of application of HAP emission control technologies, we have concerns about the applicability of HAP emission control technology to them.

B. What About Stationary Combustion Turbines Located at Area Sources? The proposed rule does not apply to stationary combustion turbines located at an area source of HAP emissions. In developing our Urban Air Toxics Strategy, we identified area sources we believe warrant regulation to protect the environment and the public health and satisfy the statutory requirements in section 112 of the CAA pertaining to area sources. Stationary combustion turbines located at area sources were not included on that list. As a result, the proposed rule does not apply to these stationary combustion turbines.

C. What Is the Affected Source? The proposed rule applies to any stationary combustion turbine located at a major source. Consequently, stationary combustion turbines located at major sources of HAP emissions are the affected source under the proposed rule.

D. How Did We Determine the Basis and Level of the Proposed Emission Limitations for Existing Sources? As established in section 112 of the CAA, the MACT standards must be no less stringent than the MACT floor. The MACT floor for existing sources is the average emission limitation achieved by the best performing 12 percent of existing sources.

1. MACT Floor for Existing Diffusion Flame Combustion Turbines To determine the MACT floor for existing stationary diffusion flame combustion turbines, we primarily consulted two databases: an inventory database and an emissions database. The MACT floors and MACT for stationary diffusion flame combustion turbines located at major sources were developed through the analyses of these databases. The inventory database provides population information on stationary combustion turbines in the United States ( U. S.) and was constructed in order to support the proposed rulemaking. Data in the inventory database are based on information from available databases, such as the Aerometric Information Retrieval System ( AIRS), the Ozone Transport and Assessment Group ( OTAG), and State and local agencies' databases. The first version of the database was released in 1997. Subsequent versions have been released reflecting additional or updated data. The most recent release of the database is version 4, released in November 1998. The inventory database contains information on approximately 4,800 stationary combustion turbines. The current stationary combustion turbine population is estimated to be about 8,000 turbines. Therefore, the inventory database represents about 60 percent of the stationary combustion turbines in the U. S. At least 90 percent of those turbines are assumed to be diffusion flame combustion turbines, based on VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00009 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1896 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules conversations with turbine manufacturers. The information contained in the inventory database is believed to be representative of stationary combustion turbines primarily because of its comprehensiveness. The database includes both small and large stationary combustion turbines in different user segments. Forty eight percent are `` industrial,'' 39 percent are `` utility,'' and 13 percent are `` pipeline.'' Note that independent power producers ( IPP) are included in the utility and industrial segments. We examined the inventory database for information on HAP emission control technology. There were no turbines controlled with oxidation catalyst systems in the inventory database so we used information supplied by catalyst vendors. There are about 200 oxidation catalyst systems installed in the U. S. The only control technology currently proven to reduce HAP emissions from stationary diffusion flame combustion turbines is an oxidation catalyst emission control device, such as a CO oxidation catalyst. These control devices are used to reduce CO emissions and are currently installed on several stationary combustion turbines. However, less than 3 percent of existing stationary diffusion flame combustion turbines in the U. S., based on information in our inventory database and information from catalyst vendors, are equipped with oxidation catalyst emission control devices; thus, the average of the best performing 12 percent of existing diffusion flame combustion turbines is no HAP emissions reductions. We also investigated the use of good operating practices for stationary diffusion flame combustion turbines to determine if the use of such practices might identify a MACT floor. There are no references in the inventory database to good operating practices for any stationary combustion turbines. Most stationary diffusion flame combustion turbines will not operate unless preset conditions established by the manufacturer are met. Stationary diffusion flame combustion turbines, by manufacturer design, permit little operator involvement and there are no operating parameters, such as air/ fuel ratio, for the operator to adjust. We concluded, therefore, that there are no specific good operating practices which could reduce HAP emissions or which could serve to identify a MACT floor. We also investigated switching fuels in existing diffusion flame combustion turbines using fuels which result in higher HAP emissions with fuels that result in lower HAP emissions. When we compared the HAP emissions of the various fuels from combustion turbines using the April 2000 revision of Chapter 3.1 ( Stationary Gas Turbines) of `` Compilation of Air Pollutant Emission Factors AP   42, Fifth Edition, Volume 1: Stationary Point and Area Sources,'' we could not find a fuel that was clearly less HAP emitting. The summation of emission factors for various HAP when using natural gas ( usually considered the cleanest fuel), diesel fuel, landfill, or digester gas were comparable based on the emission factor information that is available. Therefore, we could not identify a MACT floor based on use of a particular fuel. Another approach we investigated to identify a MACT floor was to review the requirements in existing State regulations and permits. No State regulations exist for HAP emission limits for stationary combustion turbines. Only one State permit limitation for a single HAP ( benzene) was identified. Therefore, we were unable to use State regulations or permits to identify a MACT floor. As a result, we concluded the MACT floor for existing stationary diffusion flame combustion turbines is no emissions reductions.

2. MACT for Existing Diffusion Flame Combustion Turbines To determine MACT for existing stationary diffusion flame combustion turbines, we evaluated regulatory alternatives more stringent than the MACT floor. For existing diffusion flame sources, in terms of an emission control technology which could serve as the basis for MACT, we considered two beyond the floor options. The first option considered was the use of an oxidation catalyst emission control device. However, we concluded that the incremental cost per ton of HAP removed for this option is excessive. The incremental cost per ton is the difference in annual costs between this regulatory option and the MACT floor divided by the difference in annual emissions. It is often used as a measure of the economic feasibility of applying emission control technology to a source. We also considered the nonair health, environmental, and energy impacts of an oxidation catalyst system, as discussed previously in this preamble, and concluded that there would be only a small energy impact and no nonair health or environmental impacts. However, as stated above, we did not adopt this regulatory option due to cost considerations. The second option considered was to switch fuels in existing turbines using fuels which result in higher HAP emissions with fuels that result in lower HAP emissions. As stated above, we could not find a fuel that was clearly less HAP emitting. Therefore, we could find no basis to further consider fuel switching as a beyond the floor HAP emissions reductions option. We were unable to identify any other beyond thefloor regulatory option to consider. As discussed above, we are not aware of any specific good operating practices for diffusion flame turbines that could reduce HAP emissions. As a result, we concluded that MACT for existing diffusion flame combustion turbines is the MACT floor ( i. e., no emissions reductions).

3. MACT Floor for Existing Lean Premix Combustion Turbines There are an estimated 800 lean premix combustion turbines in the U. S., of which 160 are estimated to be major sources. For existing lean premix combustion turbines, we must establish a MACT floor which represents the average emission limitation achieved by the best performing 12 percent of the existing sources for which we have emissions information. We have emissions information on five existing lean premix combustion turbines. Therefore, we plan to establish the MACT floor based on the performance of the best performing lean premix combustion turbine. ( This best performing turbine represents the top 20 percent of the existing turbines for which we have emissions information and will also be used to establish the MACT floor for new lean premix combustion turbines.) The best performing existing lean premix combustion turbine achieved a level of formaldehyde concentration emission which averaged 6.1 parts per billion ( ppb) formaldehyde at 15 percent oxygen ( O2). This is the best performer out of five lean premix combustion turbine tests for which we have data. The three run average formaldehyde emissions from these five turbines ranged from 6.1 to 41 ppb formaldehyde. The formaldehyde concentrations for the individual runs for the best performing turbine were 5.1 ppb, 5.7 ppb, and 7.7 ppb. The test method that was used to measure the emissions from the best performing turbine was California Air Resources Board ( CARB) Method 430. We do not believe that the MACT emission limit should be set lower than the limit of detection of the method. If it were, we could not determine whether a source with test results at the limit of detection was actually in compliance with the MACT emission limit. For the test runs on the best VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00010 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1897 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules 1 1998 National Air Quality and Emission Trends Report, Table 5   2 and Figure 5   1a. performing turbine, we determined that the method had a minimum detection level ( MDL) of between 2 and 3 ppb formaldehyde. We expect the MDL to vary somewhat in actual practice and, thus, do not assume that the MDL would be the same if the method were run by another person or at another laboratory. We have no information regarding the distribution of the CARB Method 430 MDL actually achieved by other testers. We want to ensure that the MACT floor reflects the variability in the limit of detection determined by different, competent testers throughout the U. S. using the same method, i. e., CARB Method 430. We only have one test, the test conducted on the best performing turbine, to try to determine a limit of detection for this method, and this is not enough information to determine the variability in the limit of detection among different testers. If we had sufficient information on the limit of detection determined by different competent testers using Method 430, under similar conditions, we would analyze the results to determine the average limit of detection and its standard deviation. To establish a limit of detection that would be achievable by approximately 99 percent of all the testers, we would add three times the standard deviation to the average limit of detection. Since we do not have this information, we can attempt to estimate it. We believe that it is reasonable to assume that the standard deviation of the limit of detection is no greater than the single estimate of the limit that we have. If we multiply the single value of the limit of detection by three and add it to itself, the result is an estimate of the upper bound for the limit of detection that is four times the single measured value that we have. Based on the considerations above, the lowest MACT floor that we believe would take into account the variability in the MDL is 12 ppb. This level provides a safety factor of four to account for uncertainty in whether testers could routinely achieve a limit of detection of 2 to 3 ppb formaldehyde. The combustion turbine MACT would be a national standard, and therefore, the MACT limit should reflect variations in the performance of the best performing turbine that could occur. There are two major sources of variability that together produce the total variability observed in the emissions sample results. These sources of variability are: the actual variability in the emissions, and the variability associated with procedures for sampling and analyzing the emissions samples. We believe there is substantial basis to conclude that sources of variability unrelated to turbine performance account for the differences in formaldehyde emissions concentrations between the five turbines. We discuss these sources of variability in more detail below. When we began investigating the possible sources of the actual ( nonsampling non analytical) variability in lean premix combustion turbine emissions, we realized that turbine performance was only one of several possible sources of that variability, and that turbine emissions also could vary widely due to environmental and operational factors that are unrelated to turbine performance and that are beyond an operator's control. Specifically, formaldehyde concentrations are expected to vary temporally ( e. g., seasonally) and spatially ( e. g., geographically) due to environmental and operational factors such as temperature, humidity, atmospheric pressure, fuel quality, and the concentrations of formaldehyde present in the ambient air. It is our judgement that if the turbines were tested at various times during the year and at various locations throughout the U. S., the concentration of formaldehyde emitted by a given turbine could vary by a factor of seven or more, solely due to geographic and temporal differences in temperature, humidity, atmospheric pressure, fuel quality, and formaldehyde concentration in the ambient air. This factor is based not only on the short term variability of the data for the turbine with the lowest reported formaldehyde emissions, but also on the test data from all five turbines. Variations in temperature, humidity, atmospheric pressure, and fuel quality are known to have resulted in fluctuations in criteria pollutant stack concentrations ( e. g., NOX, VOC, and CO), and we anticipate that they also would cause variations in formaldehyde concentrations in the combustion turbine stack. An owner or operator cannot control the variability of environmental parameters such as ambient temperature, humidity, or atmospheric pressure. With regard to fuel quality, an owner or operator cannot control the quality of the natural gas delivered through a pipeline, or the nature and concentration of natural gas additives or contaminants. The five turbines for which we have formaldehyde emissions data operate at four locations in the Western U. S. that are at considerably different altitudes. Moreover, each of the five turbines was sampled over only a 3 hour period, and the five sampling events occurred in four different months of the year: April, May, June ( two turbines), and December. Therefore, we believe that the variability in formaldehyde concentration of the turbine emissions will be greater than the variability reflected in the 3 hour sampling period. Furthermore, we believe that the variability observed in the available turbine emissions data may reflect the variability of formaldehyde concentrations in ambient air   much of which is due to natural causes. The average concentration of formaldehyde in ambient air varies between 2 and 25 ppb within the U. S., with a U. S. annual average urban concentration of 5.17 ug/ m3 ( 4.2 ppb). 1 The difference between hourly maximum and minimum formaldehyde concentrations across the U. S. would be even greater than the average annual 23 ppb range in U. S. formaldehyde concentrations. We do not have information that specifically shows that the ambient concentration of formaldehyde affects the stack outlet concentration of formaldehyde. We expect that some formaldehyde, especially the portion that goes through the combustors, would be destroyed. However, about two thirds of the inlet combustion turbine air bypasses the combustors. We are not sure that all of the ambient formaldehyde that enters with the combustion air is destroyed and, therefore, ambient formaldehyde may affect the formaldehyde concentration in the outlet stack of the combustion turbine. For example, if half of the ambient formaldehyde passes through to the outlet stack, the annual average contribution of ambient formaldehyde to the stack formaldehyde concentration may be in the 10 ppb range in some parts of the U. S. This means that hourly formaldehyde emissions from the outlet stack of a given turbine could differ by over 10 ppb based solely on the region of the country where the turbine is located. Sampling variability is a result of the fact that it is impossible to collect two samples in exactly the same way. Sampling variability occurs both when an individual intends to collect replicate samples of the same emissions stream, and when sampling is conducted by different personnel using different procedures and different equipment under different physical conditions. If the same sampling personnel collect a suite of samples using the same equipment and procedures, the variability of the sampling results will be reduced. However, a given individual or a given piece of equipment may impart bias, a VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00011 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1898 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules systematic error, into the sampling procedure. In the context of an aggregate of data collected by different personnel using different procedures and different equipment under different physical conditions, this bias could have the effect of increasing the variability of the data. The emissions sample results for the five turbines evaluated for the proposed rule were provided by state agencies, and samples were not collected by the same sampling personnel, or even personnel acting in coordination with one another and following the same sampling plan and methodologies, increasing the nonsystematic sampling induced variability across the five sets of turbine samples and also increasing the chance that any bias imposed on each set of turbine samples might also increase the variability of the results. Moreover, two different sampling and analysis procedures were used to collect the samples, EPA Method 0011 and CARB Method 430, likely introducing additional variability into the sampling procedure. For example, EPA generally recognizes that the quality assurance/ quality control ( QA/ QC) protocols for CARB Method 430 are more rigorous than those for EPA Method 0011. Similar to sampling variability, variability occurs when samples are analyzed at the same time in the same laboratory ( e. g., variability is seen in the results of a laboratory's repeated analysis of the same sample) and occurs when samples are analyzed by different laboratories. For example, analytic variability may result from the use of different analytical procedures, different equipment, different laboratory environments, different reagents, different sampling handling procedures, and different analysts. The emissions samples evaluated for the proposed rule were analyzed in different laboratories, by different analysts, and using two different analytical procedures. The EPA suspects that sampling and analytic variability may be a significant source of the variability of formaldehyde emissions results reported for the five tested turbines, and that if stricter QA/ QC protocols were followed, the results for the five turbines might have been closer in magnitude. One measure of overall variability ( i. e., variability from all sources   environmental, operational, test method, etc.) is the variability of formaldehyde concentration that the best performing turbine demonstrated during the three test runs. The formaldehyde concentration varied between 5.1 and 7.7 ppb formaldehyde, a factor of 1.5 during only a 3 hour period. Another measure of formaldehyde concentration variability is the variability in formaldehyde concentration from the five lean premix combustion turbines tested. As stated previously, the average formaldehyde concentration varied between 6.1 and 41 ppb ( a factor of seven). We reviewed the emission test reports and could not find any specific reason to account for the variability. These tests were properly conducted, and the lean premix combustion turbines were operating properly. Therefore, we believe that at least some portion, and possibly all, of that variability is due to factors other than turbine performance. As a result, we believe that some variability in formaldehyde concentration of the best performing turbine will occur beyond the variability reflected by the three test runs. It is our judgement that if the best performing turbine were tested at various times during the year and at various locations throughout the U. S., the overall formaldehyde concentration of the best performing turbine could vary by a factor of seven or more. This factor is based on the short term variability of the test data from the best performing turbine and also on the test data from the five turbine tests mentioned previously. Therefore, we believe that 43 ppbvd formaldehyde is a reasonable approximation of the performance of the best performing turbine, taking into account all of the types of variability discussed above. As a result, we are proposing an emission limit of 43 ppbvd formaldehyde as the MACT floor for existing lean premix combustion turbines. The lean premix combustor turbine technology varies to some extent regarding its uncontrolled emissions of NOX and CO and possibly HAP. The data that we have obtained for the five source tests were based primarily on lean premix combustor turbines that can achieve lower than 15 ppm NOX and less than 5 ppm CO ( at full load) at 15 percent O2 without add on controls. Lean premix combustor turbines which have these characteristics are the types of lean premix combustor turbines that we believe will most likely achieve the 43 ppb formaldehyde emission limit. Other types of lean premix combustor turbines which achieve 45 ppm NOX and as high as 200 ppm CO at 15 percent O2 may not achieve the 43 ppb formaldehyde emission limit. Typically, the lean premix combustor turbines in the latter category are smaller aeroderivative turbines. Therefore, we realize that not all lean premix combustor turbines will be able to achieve the 43 ppb formaldehyde emission limitation and some will have to install add on controls. Most new turbines projected to be installed at power plants are expected to be able to achieve the 43 ppb emission limitation. We request public comment on the proposed MACT floor level for existing lean premix combustion turbines. We are particularly interested in obtaining information on the annual/ seasonal and geographic variability in formaldehyde emissions that occur for lean premix combustion turbines. Formaldehyde emission test reports that were conducted over time for the same lean premix combustion turbine would be especially helpful. We are also soliciting information regarding the contribution of ambient formaldehyde to the variability of outlet stack concentrations of formaldehyde.

4. MACT for Existing Lean Premix Combustion Turbines To determine MACT for existing stationary lean premix combustion turbines, we evaluated regulatory alternatives more stringent than the MACT floor. For existing lean premix turbines, in terms of an emission control technology which could serve as the basis for MACT, we considered the use of an oxidation catalyst emission control device. According to catalyst vendors, oxidation catalyst emission control is being used on some existing lean premix combustion turbines, however, we lack specific data regarding the performance of turbines with such controls. The concentration of formaldehyde in the exhaust stream from lean premix combustion turbines is already significantly lower than the concentration of formaldehyde in the exhaust stream from diffusion flame combustion turbines, and any reduction achieved by oxidation catalyst control would be difficult to measure. Thus, we concluded that the incremental cost per ton of HAP removed for that option is excessive. We also considered the use of good operating practices to reduce HAP emissions, but determined that we could not identify specific good operating practices that would reduce HAP emissions. Similarly, we also considered requiring the use of a particular fuel to reduce HAP emissions but concluded that fuel switching would not result in further HAP emissions reductions. As a result, we are proposing to set MACT for existing lean premix combustion turbines at the MACT floor ( i. e., 43 ppbvd formaldehyde).

VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00012 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1899 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules E. How Did We Determine the Basis and Level of the Proposed Emission Limitations and Operating Limitations for New Sources?

For new sources, the MACT floor is defined as the emission control that is achieved in practice by the best controlled similar source.

1. MACT Floor for New Diffusion Flame Combustion Turbines To identify the MACT floor for new stationary combustion turbines located at major sources, we consulted the inventory database and oxidation catalyst vendor information. As mentioned earlier, oxidation catalyst emission control devices are currently installed on about 3 percent of stationary diffusion flame combustion turbines. This 3 percent represents about 200 stationary combustion turbines. We also considered whether the best controlled diffusion flame combustion turbine might be using good operating practices or a particular fuel that would reduce HAP emissions further and concluded, as we had previously in this preamble for existing sources, that we could not identify specific good operating practices that would reduce HAP emissions, and that fuel switching would not result in further HAP emissions reductions. We concluded, therefore, that the level of HAP emission control achieved by the use of oxidation catalyst emission control devices is the MACT floor for new stationary combustion turbines. After establishing this basis for the MACT floor, we determined the level of performance based on the data available in the emissions database. The emissions database, which is a compilation of available HAP emission test reports, was created for the purpose of supporting rulemaking for the proposed rule. The majority of HAP emission test reports collected were conducted in California as part of the AB 2588 ( Air Toxics `` Hot Spots'' Information Assessment Act of 1987) program. Complete copies of HAP emission test reports for stationary combustion turbines were gathered from all air districts in California and from other sources, such as the EPA Source Test Information Retrieval System ( STIRS). Other States, including Washington, Texas, Pennsylvania, and New Jersey, and trade associations such as the Western States Petroleum Association ( WSPA) and the Gas Research Institute ( GRI) were also contacted for available HAP emission test reports. We then examined the emission control efficiency achieved by an oxidation catalyst emission control device on a stationary combustion turbine. We concluded that CO emission reductions are a good surrogate for HAP emissions reductions for oxidation catalyst emission control devices. This conclusion that CO emission reductions are a good surrogate for HAP emissions reductions achieved through the use of oxidation catalyst emission control devices is also supported by data we have collected from the use of oxidation catalyst emission control devices on stationary reciprocating internal combustion engines ( RICE). These data from stationary RICE also show a direct relationship between CO emission reductions and HAP emissions reductions. When oxidation catalyst emission control devices are used to reduce CO emissions, they will reduce HAP emissions. The emissions database contains several emission test reports that measured HAP and CO emissions from stationary combustion turbines, but no emission test reports that measure the emission reduction efficiency of an oxidation catalyst emission control device ( measuring CO and HAP emissions both before and after the control device). However, we obtained information from a catalyst vendor for two tests for one turbine. The results of those tests show that a CO reduction of 95 to 98 percent was achieved using an oxidation catalyst control system. We reviewed the test report for the data to assure that the turbine was operated correctly and that there was no turbine or control device malfunction; we found no discrepancy. In addition to emissions testing data, we reviewed design data from oxidation catalyst vendors for the systems installed in the U. S. The typical emission reduction for turbines that have been installed is 90 percent CO emission reduction, with a few systems that are designed to be 95 percent or greater. We reviewed other factors such as operator training in addition to the control technology itself that could potentially result in better emission reduction, but we found no effect of those factors on the control efficiency. Based on the conclusions and data, we believe that 95 percent represents the level of control that can be achieved by the best controlled similar source. As a result, we concluded that the level of performance associated with the MACT floor ( i. e., use of an oxidation catalyst emission control device) is an emission reduction efficiency of 95 percent or more for CO. The MACT floor for new stationary diffusion flame combustion turbines is, therefore, a CO emission reduction efficiency of 95 percent or more, using an oxidation catalyst control system.

2. MACT for New Diffusion Flame Combustion Turbines We were unable to identify any beyond the floor regulatory alternatives for new stationary combustion turbines. We know of no emission control technology currently available which can reduce HAP emissions to levels lower than that achieved through the use of oxidation catalyst emission control devices. Similarly, we know of no work practice that could further reduce HAP emissions. In addition, fuel switching will not result in further reductions of HAP emissions. We concluded, therefore, that MACT for new diffusion flame stationary combustion turbines is equivalent to the MACT floor. It should be noted that the majority of new combustion turbines are expected to be lean premix combustion turbines based on the significantly reduced emissions of NOX, CO, and formaldehyde. We estimate that less than 5 percent of new combustion turbines will be diffusion flame. Dieselfired combustion turbines cannot be operated in the lean premix mode, and these turbines would have to install an oxidation catalyst system.

3. MACT Floor for New Lean Premix Combustion Turbines To determine the MACT floor for new stationary lean premix combustion turbines, we based our analysis on the same emissions data for formaldehyde that we used for the existing MACT floor. The MACT floor for existing lean premix combustion turbines is based on the performance of the best performing lean premix combustion turbine; this same level of performance can, therefore, be used to determine the MACT floor for new lean premix combustion turbines. As discussed previously in the existing source MACT, we believe that 43 ppbvd formaldehyde represents the best performing turbine. The MACT floor for new lean premix combustion turbines is, therefore, an emission limit of 43 ppbvd formaldehyde.

4. MACT for New Lean Premix Combustion Turbines To determine MACT for new stationary lean premix combustion turbines, we evaluated regulatory alternatives more stringent than the MACT floor. As with existing lean premix combustion turbines, we considered the use of an oxidation catalyst control system. However, although catalyst vendors have indicated that some existing lean VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00013 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1900 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules premix combustion turbines are using oxidation catalyst emission control, we lack specific data regarding the performance of turbines with such controls. The HAP concentration in the lean premix combustion turbine exhaust is very low and, therefore, would be difficult to measure if it were further reduced through the installation of an oxidation catalyst. Due to the low HAP levels, the cost per ton of HAP removed would be very high. We concluded, therefore, that MACT for new stationary lean premix combustion turbines is equivalent to the MACT floor.

5. MACT for Other Subcategories Although the proposed rule would apply to all stationary combustion turbines located at major sources of HAP emissions, emergency stationary combustion turbines, limited use stationary combustion turbines, stationary combustion turbines which fire landfill gas or digester gas as their primary fuel, and stationary combustion turbines of less than 1 MW rated peak power output are not required to meet the emission limitations or operating limitations. For each of the subcategories of stationary combustion turbines, as mentioned earlier, we have concerns about the applicability of emission control technology. For example, emergency stationary combustion turbines operate infrequently. In addition, when called upon to operate they must respond immediately without failure and without lengthy startup periods. This infrequent operation limits the applicability of HAP emission control technology. Limited use stationary combustion turbines also operate infrequently. As with emergency stationary combustion turbines, it is this infrequent operation that limits the applicability of HAP emission control technology. Landfill and digester gases contain a family of silicon based gases called siloxanes. Combustion of siloxanes forms compounds that can foul postcombustion catalysts, rendering catalysts inoperable within a very short time period. Pretreatment of exhaust gases to remove siloxanes was investigated. However, no pretreatment systems are in use and their long term effectiveness is unknown. We also considered fuel switching for this subcategory of turbines. Switching to a different fuel such as natural gas or diesel would potentially allow the turbine to apply an oxidation catalyst emission control device. However, fuel switching would defeat the purpose of using this type of fuel which would then either be allowed to escape uncontrolled or would be burned in a flare with no energy recovery. We believe that switching landfill or digester gas to another fuel is inappropriate and is an environmentally inferior option. For stationary combustion turbines of less than 1 MW rated peak power output, we have concerns about the effectiveness of scaling down the oxidation catalyst emission control technology. Just as there are often unforeseen problems associated with scaling up a technology, there can be problems associated with scaling down a technology. As a result, we identified subcategories for each of these types of stationary combustion turbines and investigated MACT floors and MACT for each subcategory. As expected, since we identified these types of stationary combustion turbines as separate subcategories based on concerns about the applicability of emission control technology, we found no stationary combustion turbines in these subcategories using any emission control technology to reduce HAP emissions. As discussed above, we are not aware of any work practices that might constitute a MACT floor, nor did we find that the use of a particular fuel results in HAP emissions reductions. The MACT floor, therefore, for each of these subcategories is no emissions reduction. Despite our concerns with the applicability of emission control technology, we examined the cost per ton of HAP removed for these subcategories. Whether our concerns are warranted or not, we consider the incremental cost per ton of HAP removed excessive   primarily because of the very small reduction in HAP emissions that would result. We also considered the nonair health, environmental, and energy impacts of an oxidation catalyst system, as discussed previously in this preamble, and concluded that there would be only a small energy impact and no nonair health or environmental impacts. However, as stated above, we did not adopt this regulatory option due to cost considerations and concerns about the applicability of this technology to these subcategories. We were not able to identify any other means of achieving HAP emissions reductions for these subcategories. As a result, for all of these reasons, we conclude that MACT for these subcategories is the MACT floor ( i. e., no emissions reductions). F. How Did We Select the Format of the Standard for New Diffusion Flame Combustion Turbines?

We are proposing two options for complying with the standard for new diffusion flame combustion turbines. You may reduce CO by 95 percent if you use an oxidation catalyst emission control device, or reduce the concentration of formaldehyde in the exhaust from the turbine to 43 ppb by volume or less, dry basis, at 15 percent oxygen. We considered proposing an emission limitation for HAP, but are proposing a CO emission reduction limitation as a surrogate for a HAP emission limitation. We have decided to propose the use of the CO emission reduction limitation as a surrogate for the HAP emission limitation, because CO monitoring is currently being used by combustion turbine owners and operators, it is significantly easier and less expensive to measure and monitor CO than to measure and monitor each HAP, and because we believe that CO reduction is a good measure of performance of the oxidation catalyst emission control device. Monitoring equipment for CO is readily available, which is not the case for HAP monitoring equipment. We are also proposing a percent reduction in CO emissions as the emission limitation, rather than a single value for CO emissions. The data upon which MACT are based show that while the level of CO emissions entering an oxidation catalyst emission control device may vary, the oxidation catalyst emission control device is able to maintain a CO emission reduction efficiency of 95 percent or more. We are also proposing an alternative emission limitation for formaldehyde emissions. You may choose to comply with the emission limitation for CO emission reduction ( if you use an oxidation catalyst emission control device) or you may choose to comply with the emission limitation for formaldehyde emission concentration ( if you use some means other than an oxidation catalyst control device to reduce HAP emissions). We would like to promote the development and eventual use of alternative emission control technologies ( including pollution prevention technologies) to reduce HAP emissions, and we believe an alternative emission limitation written in terms of formaldehyde emissions will serve to do so. We are soliciting information on HAP and CO emissions data from alternative emission control technologies during the comment period. We are particularly interested in obtaining test reports VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00014 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1901 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules where HAP and CO emissions reductions were measured with methods that we are recommending to be used to measure HAP in the proposed rule. For the emission limitation, we propose to use formaldehyde as a surrogate for all HAP. Formaldehyde is the HAP emitted in the highest concentrations from stationary combustion turbines. In addition, the emission data show that HAP emission levels and formaldehyde emission levels are related, in the sense that when emissions of one are low, emissions of the other are low and vice versa. This leads us to conclude that emission control technologies which lead to reductions in formaldehyde emissions will lead to reductions in HAP emissions. The emission limitation for formaldehyde is in units of parts per billion, and all measurements must be corrected to 15 percent oxygen, dry basis, to provide a common basis. A volume concentration was chosen for the emission limitation because it can be measured directly. We based the alternative emission limitation on the ability of lean premix technology to reduce emissions to 43 ppbvd ( at 15 percent oxygen). The reduction in formaldehyde emissions is approximately equivalent to that achieved when CO emissions are reduced by 95 percent through the use of an oxidation catalyst emission control device. As discussed later, we consider the cost of formaldehyde CEMS excessive for the purpose of ensuring continuous compliance with this emission limitation for formaldehyde emissions. As a result, we selected stack emission testing to demonstrate compliance with the emission limitation.

G. How Did We Select the Initial Compliance Requirements? The emissions tests which form the basis of the proposed rule were conducted using EPA or CARB test methods. The proposed rule requires the use of these EPA or CARB test methods to determine compliance. This ensures that the same procedures that were used to obtain the emission data upon which the emission limitations are based are used for compliance testing. By using the same test methods, we eliminate the possibility of measurement bias and interference influencing determinations of compliance. For sources complying with the emission limitation to reduce CO emissions, an initial performance evaluation is required. The performance evaluation will validate performance of the CEMS. The proposed rule also requires an annual relative accuracy test audit ( RATA) to ensure that performance of the CEMS does not deteriorate over time. The first 4 hour period following this performance evaluation of the CO CEMS will be used to determine initial compliance with the CO emission reduction limitation. New and reconstructed sources and existing lean premix combustor turbines complying with the emission limitation to reduce formaldehyde emissions are required to conduct an initial performance test. The purpose of the initial test is to demonstrate initial compliance with the formaldehyde emission limitation.

H. How Did We Select the Continuous Compliance Requirements? If you must comply with the emission limitations, continuous compliance with these requirements is required at all times except during startup, shutdown, and malfunction of your stationary combustion turbine. You are not required to develop a startup, shutdown or malfunction plan since we do not believe meaningful procedures could be developed. We consider the use of CEMS the best means of ensuring continuous compliance with emission limitations, and alternatives to CEMS are considered only if we consider the use of a CEMS technically or economically infeasible. For sources complying with the emission limitation for CO emission reduction, we believe it is feasible to require a CEMS because the costs for a CO CEMS are reasonable. Thus, the proposed rule requires the use of a CO CEMS to continuously monitor the reduction in CO emissions. For sources complying with the emission limitation for formaldehyde emissions, we also considered requiring a CEMS; however, we concluded that the costs of a formaldehyde CEMS were excessive. We considered requiring those sources to continuously monitor operating load to demonstrate continuous compliance because the data establishing the formaldehyde outlet concentration level are based on tests that were done at high loads. However, we believe that the performance of a stationary lean premix combustion turbine at high load is also indicative of its operation at lower loads. In fact, the operator can make no parameter adjustments that would lead to lower emissions. We request comments on the continued monitoring of stationary lean premix combustion turbines that have demonstrated initial compliance. The stationary lean premix combustion turbines are low NOX emitting and are permitted to continuously attain the permitted NOX levels. The same technology that results in the maintenance of low NOX levels is also related to the achievement of low HAP emissions. Therefore, we would like to solicit comments on the feasibility of requiring no additional testing or monitoring after the lean premix stationary combustion turbine has demonstrated initial compliance and is relying on the NOX permit levels, or low NOX levels characteristic of lean premix combustor turbines ( e. g. NOX levels guaranteed by the manufacturer) if there are no permit levels, to assure continuing good performance. We are proposing this in an attempt to streamline the continuous testing, monitoring, and reporting requirements. Finally, since we are unsure what new HAP emission control technologies might emerge, we do not know whether it will be necessary to establish additional operating limitations to ensure continuous compliance with the formaldehyde emission limitation for sources that are not lean premix or diffusion flame. Thus, as outlined earlier, the proposed rule requires you to petition the Administrator for approval of additional operating limitations or for approval of no additional operating limitations.

I. How Did We Select the Monitoring and Testing Methods to Measure These Low Concentrations of CO and Formaldehyde? We believe CEMS are available which can measure CO emissions at the low concentrations found in the exhaust from a stationary combustion turbine following an oxidation catalyst emission control device. Our performance specifications for CO CEMS ( PS4 and PS4A), however, have not been updated recently and do not reflect the performance capabilities of such systems at these low CO concentration levels. As a result, we solicit comments on the performance capabilities of state ofthe art CO CEMS and their ability to accurately measure the low concentrations of CO experienced in the exhaust of a stationary combustion turbine following an oxidation catalyst emission control device. We also solicit comments with specific recommendations on the changes we should make to our performance specifications for CO CEMS ( PS4 and PS4A) to ensure the installation and use of CEMS which can be used to determine compliance with the proposed emission limitation for CO emission reduction. In addition, we VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00015 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1902 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules solicit comments on the availability of instruments capable of meeting the changes they recommend to our performance specifications for CO CEMS. Today's proposal specifies the use of Method 10 as the reference method to certify the performance of the CO CEMS. We also believe Method 10 is capable of measuring CO concentrations as low as those experienced in the exhaust of a stationary combustion turbine following an oxidation catalyst emission control device. However, the performance criteria in addenda A of Method 10 have not been revised recently and are not suitable for certifying the performance of a CO CEMS at these low CO concentrations. Specifically, we believe the range and minimum detectable sensitivity should be changed to reflect target concentrations as low as 0.1 parts per million ( ppm) CO in some cases. We also expect that dual range instruments will be necessary to measure CO concentrations at the inlet and at the outlet of an oxidation catalyst emission control device. As a result, we solicit comments with specific recommendations on the changes we should make to Method 10 and the performance criteria in addenda A. We also solicit comments on the availability of instruments capable of meeting the changes they recommend to Method 10 and the performance criteria in addenda A, while also meeting the remaining addenda A performance criteria. With regard to formaldehyde, we believe systems meeting the requirements of Method 320, a selfvalidating FTIR method, can be used to attain detection limits for formaldehyde concentrations below 43 ppbvd. We expect path lengths in the range of 100 to 125 meters and state of the art digital signal processing ( to reduce signal to noise ratio) would be needed. Method 320 also includes formaldehyde spike recovery criteria, which require spike recoveries of 70 to 130 percent. While we believe FTIR systems can meet Method 320 and measure formaldehyde concentrations at these low levels, we have limited experience with their use. As a result, we solicit comments on the ability and use of FTIR systems to meet the validation and quality assurance requirements of Method 320 for the purpose of determining compliance with the emission limitation for formaldehyde emissions. As an alternative to Method 320, we are proposing Method 323 for natural gas fired sources. Method 323 uses the acetyl acetone colorimetric method to measure formaldehyde emissions in the exhaust of natural gas fired, stationary combustion sources. We believe the proposed method can measure low concentrations of formaldehyde at a cost which is less than or equal to the cost of testing using Method 320; therefore, we solicit comments on the use of Method 323 by natural gas fired sources to demonstrate compliance with the formaldehyde emission limitation. We also believe CARB Method 430 and EPA SW   846 Method 0011 are capable of measuring formaldehyde concentrations at these low levels. Accordingly, we solicit comments on the use of CARB 430 and EPA SW   846 Method 0011 to determine compliance with the emission limitations for formaldehyde. Based on the comments we receive on CO CEMS, we anticipate revising Method 10 and our performance specifications ( PS4 and PS4A) for CO CEMS to ensure the installation and use of CEMS suitable for determining compliance with the emission limitation for CO emission reduction. If we should promulgate today's proposed rule for stationary combustion turbines before completing these revisions, however, we may require all new and reconstructed stationary combustion turbines subject to the final rule to demonstrate compliance with the formaldehyde emission limitation, or a formaldehyde percent reduction limitation similar to the CO percent reduction emission limitation, until we have adopted final revisions to Method 10 and our performance specifications for CO CEMS. On the other hand, if the comments we receive lead us to conclude that CO CEMS are not capable of being used to determine compliance with the emission limitation for CO emission reduction, there are several alternatives we may consider. One alternative would be to delete the proposed percent reduction emission limitation for CO and require compliance with a comparable formaldehyde percent reduction limitation. This alternative would require periodic stack emission testing before and after the control device and would also require owners and operators to petition the Administrator for additional operating limitations, as proposed today for those choosing to comply with the emission limitation for formaldehyde. Another alternative would be to delete the proposed emission limitation for CO emission reduction and require compliance with the proposed emission limitation for formaldehyde. This alternative could require more frequent emission testing and could also require owners and operators to petition the Administrator for additional operating limitations. Another alternative would be to require the use of Method 320 ( i. e., FTIR systems) to determine compliance with the emission limitation for CO emission reduction. This alternative could also require more frequent emission testing and require owners and operators to petition the Administrator for additional operating limitations, as proposed today for those choosing to comply with the emission limitation for formaldehyde. Based on the comments we receive on FTIR systems and Method 320, we may develop additional or revised criteria for the use of FTIR systems and/ or Method 320 to determine compliance with the emission limitation for formaldehyde. If we should conclude that neither CO CEMS or FTIR systems are capable of being used to determine compliance with the emission limitations for CO or formaldehyde emissions, then we may delete the emission limitations for CO and formaldehyde emissions and adopt an emission limitation consisting of an equipment and work practice requirement. This alternative would require the use of oxidation catalyst emission control devices which meet specific and narrow design and operating criteria. We believe the emission limitations we are proposing for CO emission reduction and formaldehyde emission concentration are superior to these alternatives for a number of reasons. We believe that the CO emission limitation is better because it is easier and cheaper to continuously monitor CO, and it has been shown to be a good surrogate for HAP. Also, we prefer to have an emission limitation rather than an equipment or work practice standard. An emission limitation is superior because it ensures that emissions are below a certain level, as demonstrated by a CEMS or performance testing. However, we solicit comments on these alternatives, should we conclude that the proposed emission limitations for CO emission reduction and formaldehyde emission concentration are inappropriate because of difficulties in monitoring or measuring CO emission reduction or formaldehyde emission concentration to determine compliance. We also solicit suggestions and recommendations for other alternatives, should we conclude the proposed emission limitations are inappropriate because of monitoring or measurement difficulties.

VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00016 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1903 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules J. How Did We Select the Notification, Recordkeeping and Reporting Requirements?

The proposed notification, recordkeeping, and reporting requirements are based on the NESHAP General Provisions of 40 CFR part 63.

IV. Summary of Environmental, Energy and Economic Impacts We estimate that 20 percent of the stationary combustion turbines affected by the proposed rule will be located at major sources. As a result, the environmental, energy, and economic impacts presented in this preamble reflect these estimates.

A. What Are the Air Quality Impacts?

The proposed rule will reduce total national HAP emissions by an estimated 81 tons/ year in the 5th year after the standards are promulgated. The emissions reductions achieved by the proposed rule would be due to the sources that install an oxidation catalyst control system. We estimate that about 10 existing lean premix combustion turbines will install oxidation catalyst control to comply with the standard. In addition, we estimate that about 5 percent of new stationary combustion turbines will install oxidation catalyst control to comply with the standards. The other 95 percent of new stationary combustion turbines will be lean premix, a pollution prevention technology which in most cases does not require the use of oxidation catalyst control. The lean premix turbines are currently being installed to meet NOX emission standards. The reduction of HAP emissions for these stationary combustion turbines is difficult to assess because it is a pollution prevention technology and is being installed to meet NOX limits, not as a result of MACT for stationary combustion turbines. Therefore, as stated previously, the HAP emissions reductions obtained by the proposed rule result only from the sources that install an oxidation catalyst control system. To estimate air impacts, national HAP emissions in the absence of the proposed rule ( i. e., HAP emission baseline) were calculated using an emission factor from the emissions database. We assumed new stationary combustion turbines are operated 8,760 hours annually. We then assumed a HAP reduction of 95 percent, achieved by using oxidation catalyst emission control devices to comply with the emission limitation to reduce CO emissions, and applied this reduction to the baseline HAP emissions to estimate total national HAP emission reduction. The total national HAP emission reduction is the sum of formaldehyde, acetaldehyde, benzene, and toluene emission reductions. In addition to HAP emission reductions, the proposed rule will reduce criteria air pollutant emissions, primarily CO emissions.

B. What Are the Cost Impacts? The national total annualized cost of the proposed rule in the 5th year following promulgation is estimated to be about $ 21.5 million. Approximately $ 267,500 of that amount is the estimated annualized cost for monitoring, recordkeeping, and reporting. To calculate the annualized control costs, we obtained estimates of the capital costs of oxidation catalyst emission control devices from vendors. We then calculated the national total annualized costs of control for the new stationary combustion turbines installing oxidation catalyst emission control in the next 5 years. Our projection of new stationary combustion turbine capacity that will come online over the next 5 years is based on review of permit data gathered by EPA from 1998 to the present time, confidential projection data from turbine manufacturers, and published sales data. We believe this projection is a reasonable estimate based on the available information.

C. What Are the Economic Impacts? The EPA prepared an economic impact analysis to evaluate the impacts the proposed rule would have on the combustion turbines producers, consumers of goods and services produces by combustion turbines, and society. The analysis shows minimal changes in prices and output for products made by the 24 industries affected by the proposed rule. The price increase for affected output is less than 0.01 percent and the reduction in output is less than 0.01 percent for each affected industry. Estimates of impacts on fuel markets show price increases of less than 0.012 percent for petroleum products and natural gas, and price increases of 0.13 and 0.17 percent for base load and peak load electricity, respectively. The price of coal is expected to decline by about 0.06 percent, and this is due to a small reduction in demand for this fuel type. Reductions in output are expected to be less than 0.16 percent for each energy type, including base load and peak load electricity. The social costs of the proposed rule are estimated at $ 13.3 million ( 1998 dollars). Social costs include the compliance costs, but also include those costs that reflect changes in the national economy due to changes in consumer and producer behavior resulting from the compliance costs associated with a regulation. In this case, changes in energy use among both consumers and producers to reduce the impact of the regulatory requirements of the proposed rule on them lead to the estimated social costs being somewhat less than the total annualized compliance cost estimate of $ 21.5 million ( 1998$). The primary reason for the much lower social cost estimate is the increase in electricity supply generated by existing unaffected sources, which mostly offsets the impact of increased electricity prices to consumers. For more information on these impacts, please refer to the economic impact analysis in the public docket.

D. What Are the Nonair Health, Environmental and Energy Impacts?

The only energy requirement is a small increase in fuel consumption resulting from back pressure caused by operating an oxidation catalyst emission control device. This energy impact is small in comparison to the costs of other impacts. There are no known nonair environmental or health impacts as a result of the implementation of the rule as proposed.

V. Solicitation of Comments and Public Participation A. General We are requesting comments on the proposed rule. We request comments on all aspects of the proposed rule, such as the proposed emission limitations and operating limitations, recordkeeping and monitoring requirements, as well as aspects you may feel have not been addressed. Specifically, we request comments on the performance capabilities of state ofthe art CO CEMS and their ability to measure the low concentrations of CO in the exhaust of a stationary combustion turbine following an oxidation catalyst emission control device. We also request comments with recommendations on changes commenters believe we should make to our performance specifications for CO CEMS ( PS4 and PS4A) of 40 CFR part 60, appendix B, and to Method 10 of 40 CFR part 60, appendix A, and the performance criteria in addenda A to Method 10. In addition, we request comments from these commenters on the availability of instruments capable of meeting the changes they recommend to our performance specifications for CO CEMS ( PS4 and PS4A) of 40 CFR part 60, Method 10 of 40 CFR part 60,

VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00017 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1904 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules appendix A, and addenda A to method 10. As also mentioned earlier, we request comments on the ability and use of FTIR systems to meet the validation and quality assurance requirements of Method 320 of 40 CFR part 63, appendix A, for the purpose of determining compliance with the emission limitation for formaldehyde emissions. In addition, we request comments on the use of Method 323 of 40 CFR part 63, appendix A, SW   846 Method 0011, and CARB 430 to determine compliance with the emission limitations for formaldehyde. We request any HAP emissions test data available from stationary combustion turbines; however, if you submit HAP emissions test data, please submit the full and complete emission test report with this data. Without a complete emission test report, which includes sections describing the stationary combustion turbine and its operation during the test as well as identifying the stationary combustion turbine for purposes of verification, discussion of the test methods employed and the Quality Assurance/ Quality Control ( QA/ QC) procedures followed, the raw data sheets, all the calculations, etc., which such reports contain, submittal of HAP emission data by itself is of little use.

B. Can We Achieve the Goals of the Proposed Rule in a Less Costly Manner? We have made every effort in developing the proposal to minimize the cost to the regulated community and allow maximum flexibility in compliance options consistent with our statutory obligations. We recognize, however, that the proposal may still require some facilities to take costly steps to further control emissions even though those emissions may not result in exposures which could pose an excess individual lifetime cancer risk greater than one in 1 million or exceed thresholds determined to provide an ample margin of safety for protecting public health and the environment from the effects of HAP. We also recognize that in some cases the proposal may require facilities to undertake emissions testing and monitoring even when the rule will not require them to reduce emissions at all. However, this is necessary to assure the proper initial performance and continuing performance of the emission reductionpollution prevention technology. We are, therefore, specifically soliciting comment on whether there are further ways to structure the proposed rule to focus on the facilities which pose significant risks and avoid the imposition of high costs on facilities that pose little risk to public health and the environment. Representatives of the plywood and composite wood products industry provided EPA with descriptions of three mechanisms that they believed could be used to implement more cost effective reductions in risk. The docket for today's proposed rule contains white papers prepared by the plywood and composite wood products industry that outline their proposed approaches ( see docket OAR   2002   0060). These approaches could be effective in focusing regulatory controls on facilities that pose significant risks and avoiding the imposition of high costs on facilities that pose little risk to public health or the environment, and we are seeking public comment on the utility of each of these approaches with respect to the proposed rule. One of the approaches, an applicability cutoff for threshold pollutants, would be implemented under the authority of CAA section 112( d)( 4); the second approach, subcategorization and delisting, would be implemented under the authority of CAA sections 112( c)( 1) and 112( c)( 9); and the third approach would involve the use of a concentration based applicability threshold. We are seeking comment on whether these approaches are legally justified and, if so, we ask for information that could be used to support such approaches. In addition, on August 21, 2002, the Agency received a petition from the Gas Turbine Association ( GTA) requesting that natural gas fueled combustion turbines be delisted and a study that they believed would justify delisting. Section 112( c)( 9) of the CAA provides EPA with the authority to delist categories or subcategories either in response to the petition of any person or upon the Administrator's own motion. The GTA states that the study supports a determination that HAP emissions from gas turbines would not result in a lifetime cancer risk greater than one in a million to the individual in the population most exposed to the emissions or non carcinogenic health risk exceeding a level which is adequate to protect public health with an ample margin of safety. We have reviewed the GTA study and responded to the GTA on October 11, 2002 with questions and areas that we believe need further analysis. The EPA's request for further information and all information provided by the petitioner to date is located in the docket for today's proposed rule. The MACT program outlined in CAA section 112( d) is intended to reduce emissions of HAP through the application of MACT to major sources of toxic air pollutants. Section 112( c)( 9) is intended to allow EPA to avoid setting MACT standards for sources or subcategories of sources that pose less than a specified level of risk to public health and the environment. The EPA requests comment on whether the proposals described here appropriately coordinate these provisions of CAA section 112. The two health based approaches focus on assessing inhalation exposures or accounting for adverse environmental impacts. EPA specifically requests comment on the appropriateness and necessity of extending these approaches to account for non inhalation exposures of certain HAP which may deposit from the atmosphere after being emitted into the air or to account for adverse environmental impacts. In addition to the specific requests for comment noted in this section, we are also interested in any information or comment concerning technical limitations, environmental and cost impacts, compliance assurance, legal rationale, and implementation relevant to the identified approaches. We also request comment on appropriate practicable and verifiable methods to ensure that sources' emissions remain below levels that protect public health and the environment. We will evaluate all comments before determining whether to include an approach in the final rule.

1. Industry HAP Emissions and Potential Health Effects For the stationary combustion turbines source category, four HAP account for essentially all of the mass of HAP emissions. Those four HAP are formaldehyde, toluene, benzene, and acetaldehyde. Additional HAP which have been measured in emission tests that were conducted at natural gas fired and distillate oil fired combustion turbines are: 1,3 butadiene, acrolein, ethylbenzene, naphthalene, polycyclic aromatic hydrocarbons ( PAH), propylene oxide, and xylenes. The following metallic HAP emissions have been measured from distillate oil fired stationary combustion turbines: arsenic, beryllium, cadmium, chromium, lead, manganese, mercury, nickel, and selenium. Of the four HAP emitted in the largest quantities by this source category, all can cause toxic effects following sufficient exposure. The potential toxic effects of these four HAP are discussed previously in this preamble. In accordance with section 112( k), EPA developed a list of 33 HAP which present the greatest threat to public VerDate Dec< 13> 2002 19: 47 Jan 13, 2003 Jkt 200001 PO 00000 Frm 00018 Fmt 4701 Sfmt 4702 E:\ FR\ FM\ 14JAP2. SGM 14JAP2 1905 Federal Register / Vol. 68, No. 9 / Tuesday, January 14, 2003 / Proposed Rules 2 See 63 FR 18754, 18765   66 ( April 15, 1998) ( Pulp and Paper Sources Proposed NESHAP) 3 `` Methods for Derivation of Inhalation Reference Concentrations and Applications of Inhalation Dosimetry.'' EPA   600/ 8   90   066F, Office of Research and Development, USEPA, October 1994. 4 `` Supplementary Guidance for Conducting Health Risk Assessment of Chemical Mixtures. Risk Assessment Forum Technical Panel,'' EPA/ 630/ R   00/ 002. USEPA, August 2000. http:// www. epa. gov/ nceawww1/ pdfs/ chem_ mix/ chem_ mix 08_ 2001. pdf. 2 health in the largest number of urban areas. Of the four predominant HAP, three ( acetaldehyde, benzene, and formaldehyde) are included on this list for the EPA's Urban Air Toxics Program. Eleven of the other emitted HAP ( acrolein, arsenic compounds, beryllium compounds, 1,3 butadiene, cadmium compounds, chromium compounds, lead compounds, manganese compounds, mercury compounds, nickel compounds, and PAH ( as POM)) also appear on the list. In November 1998, EPA published `` A Multimedia Strategy for Priority Persistent, Bioaccumulative, and Toxic ( PBT) Pollutants.'' None of the predominant four HAP emitted by stationary combustion turbine operations appears on the published list of compounds referred to in the EPA's PBT strategy. Three of the other HAP ( mercury compounds, cadmium compounds, and PAH) appear on the list. Of the HAP emitted by stationary combustion turbine operations, fifteen ( acetaldehyde, acrolein, arsenic compounds, benzene, beryllium compounds, 1,3 butadiene, cadmium compounds, chromium compounds, formaldehyde, lead compounds, mercury compounds, naphthalene, nickel compounds, PAH, and propylene oxide) are carcinogens that, at present, are not considered to have thresholds for cancer effects. Formaldehyde, however, is a potential threshold carcinogen, and EPA is currently revising the dose response assessment for formaldehyde.