National Emission Standards for Hazardous Air Pollutants From Coal- and Oil-Fired Electric Utility Steam Generating Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial-Institutional, and Small Industrial-Commercial-Institutional Steam Generating Units

Federal RegisterMay 3, 2011

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60 and 63

[EPA-HQ-OAR-2009-0234; EPA-HQ-OAR-2011-0044, FRL-9286-1]

RIN 2060-AP52

National Emission Standards for Hazardous Air Pollutants From Coal- and Oil-Fired Electric Utility Steam Generating Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial-Institutional, and Small Industrial-Commercial-Institutional Steam Generating Units

AGENCY:

Environmental Protection Agency.

ACTION:

Proposed rule.

SUMMARY:

The United States (U.S.) Environmental Protection Agency (EPA or Agency) is proposing national emission standards for hazardous air pollutants (NESHAP) from coal- and oil-fired electric utility steam generating units (EGUs) under Clean Air Act (CAA or the Act) section 112(d) and proposing revised new source performance standards (NSPS) for fossil fuel-fired EGUs under CAA section 111(b). The proposed NESHAP would protect air quality and promote public health by reducing emissions of the hazardous air pollutants (HAP) listed in CAA section 112(b). In addition, these proposed amendments to the NSPS are in response to a voluntary remand of a final rule. We also are proposing several minor amendments, technical clarifications, and corrections to existing NSPS provisions for fossil fuel-fired EGUs and large and small industrial-commercial-institutional steam generating units.

DATES:

Comments must be received on or before July 5, 2011. Under the Paperwork Reduction Act (PRA), comments on the information collection provisions are best assured of having full effect if the Office of Management and Budget (OMB) receives a copy of your comments on or before June 2, 2011.

Public Hearing:

EPA will hold three public hearings on this proposal. The dates, times, and locations of the public hearings will be announced separately. Oral testimony will be limited to 5 minutes per commenter. The EPA encourages commenters to provide written versions of their oral testimonies either electronically or in paper copy. Verbatim transcripts and written statements will be included in the rulemaking docket. If you would like to present oral testimony at one of the hearings, please notify Ms. Pamela Garrett, Sectors Policies and Programs Division (C504-03), U.S. EPA, Research Triangle Park, NC 27711, telephone number (919) 541-7966; e-mail:

garrett.pamela@epa.gov

. Persons wishing to provide testimony should notify Ms. Garrett at least 2 days in advance of each scheduled public hearing. For updates and additional information on the public hearings, please check EPA's Web site for this rulemaking,

http://www.epa.gov/ttn/atw/utility/utilitypg.html.

The public hearings will provide interested parties the opportunity to present data, views, or arguments concerning the proposed rule. EPA officials may ask clarifying questions during the oral presentations, but will not respond to the presentations or comments at that time. Written statements and supporting information submitted during the comment period will be considered with the same weight as any oral comments and supporting information presented at the public hearings.

ADDRESSES:

Submit your comments, identified by Docket ID. No. EPA-HQ-OAR-2011-0044 (NSPS action) or Docket ID No. EPA-HQ-OAR-2009-0234 (NESHAP action), by one of the following methods:

•

http://www.regulations.gov

. Follow the instructions for submitting comments.

•

http://www.epa.gov/oar/docket.html

. Follow the instructions for submitting comments on the EPA Air and Radiation Docket Web site.

•

E-mail:

Comments may be sent by electronic mail (e-mail) to

a-and-r-docket@epa.gov,

Attention EPA-HQ-OAR-2011-0044 (NSPS action) or EPA-HQ-OAR-2009-0234 (NESHAP action).

•

Fax:

Fax your comments to: (202) 566-9744, Docket ID No. EPA-HQ-OAR-2011-0044 (NSPS action) or Docket ID No. EPA-HQ-OAR-2009-0234 (NESHAP action).

•

Mail:

Send your comments on the NESHAP action to: EPA Docket Center (EPA/DC), Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, Docket ID No. EPA-HQ-OAR-2009-0234. Send your comments on the NSPS action to: EPA Docket Center (EPA/DC), Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, Docket ID. EPA-HQ-OAR-2011-0044. Please include a total of two copies. In addition, please mail a copy of your comments on the information collection provisions to the Office of Information and Regulatory Affairs, OMB, Attn: Desk Officer for EPA, 725 17th St., NW., Washington, DC 20503.

•

Hand Delivery or Courier:

Deliver your comments to: EPA Docket Center, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC 20460. Such deliveries are only accepted during the Docket's normal hours of operation (8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holiday), and special arrangements should be made for deliveries of boxed information.

Instructions:

All submissions must include agency name and respective docket number or Regulatory Information Number (RIN) for this rulemaking. All comments will be posted without change and may be made available online at

http://www.regulations.gov

, including any personal information provided, unless the comment includes information claimed to be confidential business information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through

http://www.regulations.gov

or e-mail. The

http://www.regulations.gov

Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through

http://www.regulations.gov

, your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. 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. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.

Docket:

All documents in the docket are listed in the

http://www.regulations.gov

index. Although listed in the index, some information is not publicly available (

e.g.,

CBI or other information whose disclosure is restricted by statute). Certain other material, such as copyrighted material, will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in

http://www.regulations.gov

or in hard copy at

the EPA Docket Center, Room 3334, 1301 Constitution Avenue, NW., Washington, DC. The 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 Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

For the NESHAP action: Mr. William Maxwell, Energy Strategies Group, Sector Policies and Programs Division, (D243-01), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; Telephone number: (919) 541-5430; Fax number (919) 541-5450; E-mail address:

maxwell.bill@epa.gov

. For the NSPS action: Mr. Christian Fellner, Energy Strategies Group, Sector Policies and Programs Division, (D243-01), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; Telephone number: (919) 541-4003; Fax number (919) 541-5450; E-mail address:

fellner.christian@epa.gov

SUPPLEMENTARY INFORMATION:

The information presented in this preamble is organized as follows:

I. General Information

A. Executive Summary

B. Does this action apply to me?

C. What should I consider as I prepare my comments to EPA?

D. Where can I get a copy of this document?

E. When would a public hearing occur?

II. Background Information on the NESHAP

A. Statutory Background

B. Regulatory and Litigation Background

III. Appropriate and Necessary Finding

A. Regulating EGUs Under CAA Section 112

B. The December 2000 Appropriate and Necessary Finding Was Reasonable

C. EPA Must Regulate EGUs Under Section 112 Because EGUs Were Properly Listed Under CAA Section 112(c)(1) and May Not Be Delisted Because They Do Not Meet the Delisting Criteria in CAA Section 112(c)(9)

D. New Analyses Confirm That It Remains Appropriate and Necessary To Regulate U.S. EGU HAP Under Section 112

IV. Summary of This Proposed NESHAP

A. What source categories are affected by this proposed rule?

B. What is the affected source?

C. Does this proposed rule apply to me?

D. Summary of Other Related D.C. Circuit Court Decisions

E. EPA's Response to the Vacatur of the 2005 Action

F. What is the relationship between this proposed rule and other combustion rules?

G. What emission limitations and work practice standards must I meet?

H. What are the startup, shutdown, and malfunction (SSM) requirements?

I. What are the testing requirements?

J. What are the continuous compliance requirements?

K. What are the notification, recordkeeping, and reporting requirements?

L. Submission of Emissions Test Results to EPA

V. Rationale for This Proposed NESHAP

A. How did EPA determine which subcategories and sources would be regulated under this proposed NESHAP?

B. How did EPA select the format for this proposed rule?

C. How did EPA determine the proposed emission limitations for existing EGUs?

D. How did EPA determine the MACT floors for existing EGUs?

E. How did EPA consider beyond-the-floor for existing EGUs?

F. Should EPA consider different subcategories?

G. How did EPA determine the proposed emission limitations for new EGUs?

H. How did EPA determine the MACT floor for new EGUs?

I. How did EPA consider beyond-the-floor for new EGUs?

J. Consideration of Whether To Set Standards for HCl and Other Acid Gas HAP Under CAA Section 112(d)(4)

K. How did we select the compliance requirements?

L. What alternative compliance provisions are being proposed?

M. How did EPA determine compliance times for this proposed rule?

N. How did EPA determine the required records and reports for this proposed rule?

O. How does this proposed rule affect permits?

P. Alternative Standard for Consideration

VI. Background Information on the Proposed NSPS

A. What is the statutory authority for this proposed NSPS?

B. Summary of

State of New York, et al.,

EPA

Remand

C. EPA's Response to the Remand

D. EPA's Response to the Utility Air Regulatory Group's Petition for Reconsideration

VII. Summary of the Significant Proposed NSPS Amendments

A. What are the proposed amended emissions standards for EGUs?

B. Would owners/operators of any EGUs be exempt from the proposed amendments?

C. What other significant amendments are being proposed?

VIII. Rationale for This Proposed NSPS

A. How are periods of malfunction addressed?

B. How did EPA determine the proposed emission limitations?

C. Changes to the Affected Facility

D. Additional Proposed Amendments

E. Request for Comments on the Proposed NSPS Amendments

IX. Summary of Cost, Environmental, Energy, and Economic Impacts of This Proposed NSPS

X. Impacts of These Proposed Rules

A. What are the air impacts?

B. What are the energy impacts?

C. What are the compliance costs?

D. What are the economic impacts?

E. What are the benefits of this proposed rule?

XI. Public Participation and Request for Comment

XII. Statutory and Executive Order Reviews

A. Executive Order 12866, Regulatory Planning and Review and Executive Order 13563, Improving Regulation and Regulatory Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act as Amended by the Small Business Regulatory Enforcement Fairness Act (RFA) of 1996 SBREFA), 5 U.S.C. 601

et seq.

D. Unfunded Mandates Reform Act of 1995

E. Executive Order 13132, Federalism

F. Executive Order 13175, Consultation and Coordination With Indian Tribal Governments

G. Executive Order 13045, Protection of Children From Environmental Health Risks and Safety Risks

H. Executive Order 13211, Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations

I. General Information

A. Executive Summary

In December 2000, EPA appropriately concluded that it was appropriate and necessary to regulate hazardous air pollutants (HAP) from EGUs. Today, EPA confirms that finding and concludes that it remains appropriate and necessary to regulate these emissions from EGUs. Hazardous air pollutants from EGUs contribute to adverse health and environmental effects. EGUs are by far the largest U.S. anthropogenic sources of mercury (Hg) emissions into the air and emit a number of other HAP. Both the finding in 2000 and our conclusion that it remains appropriate and necessary to regulate HAP from EGUs are supported by the CAA and scientific and technical analyses.

Mercury is a highly toxic pollutant that occurs naturally in the environment and is released into the atmosphere in significant quantities as the result of the burning of fossil fuels. Mercury in the environment is transformed into a more toxic form, methylmercury (MeHg), and because it is also a persistent pollutant, it accumulates in the food chain, especially the tissue of fish. When people consume these fish they consume MeHg, the consumption of which may cause neurotoxic effects. Children, and, in particular, developing

fetuses, are especially susceptible to MeHg effects because their developing bodies are more highly sensitive to its effects. In the December 2000 Finding, we estimated that about 7 percent of women of child-bearing age are exposed to MeHg at a level capable of causing adverse effects in the developing fetus, and that about 1 percent were exposed to 3 to 4 times that level. 65 FR 79827. Moreover, in the 1997 Mercury Study Report to Congress (the “Mercury Study”),

we concluded that exposures among specific subpopulations including anglers, Asian-Americans, and members of some Native American Tribes may be more than two-times greater than those experienced by the average U.S. population (U.S. EPA 1997 Mercury Study Report to Congress, Volume IV, page 7-2).

U.S. EPA. 1997. Mercury Study Report to Congress. EPA-452/R-97-003 December 1997.

In addition to Hg, EGUs are significant emitters of HAP metals such as arsenic (As), nickel (Ni), cadmium (Cd), and chromium (Cr), which can cause cancer; HAP metals with potentially serious noncancer health effect such as lead (Pb) and selenium (Se); and other toxic air pollutants such as the acid gases hydrogen chloride (HCl) and hydrogen fluoride (HF). Adverse noncancer health effects associated with non-Hg EGU HAP include chronic health disorders (

e.g.,

irritation of the lung, skin, and mucus membranes, effects on the central nervous system, and damage to the kidneys), and acute health disorders (

e.g.,

lung irritation and congestion, alimentary effects such as nausea and vomiting, and effects on the kidney and central nervous system). Three of the key metal HAP emitted by EGUs (As, Cr, and Ni) have been classified as human carcinogens, while another (Cd) is classified as a probable human carcinogen. Current national emissions inventories indicate that EGUs are responsible for 62 percent of the national total emissions of As, 22 percent of the national total emissions of Cr, and 28 percent of the national total emissions of Ni to the atmosphere. Notably, EGUs are also responsible for 83 percent of the national total emissions of Se to the atmosphere.

Congress recognized the threats posed by emissions of HAP and was dissatisfied with the pace of EPA's progress in reducing them prior to 1990. As a result, it enacted significant changes to the CAA that required EPA to develop stringent standards for the control of these pollutants from both stationary and mobile sources. Congress included the requirements in the 1990 CAA amendments regarding acid rain that would reduce emissions of certain criteria pollutants from EGUs and result in the installation of controls that might achieve HAP emission reduction co-benefits. For that reason, it added the requirement for EPA to make a finding before it could regulate EGUs under section 112. Specifically, Congress required in the air toxics provisions that EPA conduct a study of the public health hazards anticipated to remain from EGU HAP emissions after imposition of these other provisions and regulate EGUs under section 112 if the Agency found, after considering the results of the study, that such regulation was appropriate and necessary. Congress also required EPA to conduct a study of Hg emissions from EGUs and other sources and consider the health and environmental effects of the emissions and the availability and cost of control technologies.

Responding to Congress, EPA published the required studies detailing the hazards posed by emissions of Hg and the risks posed by emissions of Hg and other HAP from fossil fuel-fired EGUs. Following the publication of the studies and after collecting additional relevant data, EPA concluded in December 2000 that the threats to public health and the environment from emissions of Hg and other HAP from EGUs made it both appropriate and necessary to adopt regulations under section 112 to reduce the emissions of Hg and other HAP from coal- and oil-fired EGUs. As a result of its findings, EPA added these sources to the list of stationary sources subject to regulations governing the emissions of HAP. However, in a rulemaking effort completed in 2005, EPA reversed its findings and instead adopted regulations under other provisions of the CAA. The DC Circuit Court vacated the resulting regulations, noting that EPA had sidestepped important legal requirements in the CAA that govern the delisting of source categories. Those requirements provide that EPA can delist a source category only if it can demonstrate that no source within the listed category poses a lifetime cancer risk above one in one million to the individual most exposed and that emissions from no source in the category exceed the level that is adequate to protect public health with an ample margin of safety and that no adverse environmental effects will result from the emissions of any source. CAA 112(c)(9)(B). The DC Circuit Court's action restored EPA's December 2000 determination that it was appropriate and necessary to regulate coal- and oil-fired EGUs under section 112, and EGUs remain a listed source category.

EPA reasonably concluded in December 2000, based on the information available to the Agency at that time, that it was appropriate and necessary to regulate EGUs under section 112. Now, more than 10 years have passed since EPA's determination that toxic emissions from coal- and oil-fired EGUs pose a threat to public health and the environment. Although not required, EPA conducted additional, extensive technical analyses based on more recent data, and those analyses confirm that it remains appropriate and necessary to regulate HAPs from coal- and oil-fired EGUs. Accordingly and without further delay, we are proposing a set of HAP emission standards for coal- and oil-fired EGUs that can be met with existing technology that has been available for a significant time.

EPA acknowledges that although EGUs contribute significantly to the total amount of U.S. anthropogenic Hg emissions, other sources both here and abroad also contribute significantly to the global atmospheric burden and U.S. deposition of Hg. It is estimated that the U.S. contributes 5 percent to global anthropogenic Hg and 2 percent the total global Hg pool.

However, as the U.S. Supreme Court has noted in decisions as recently as

Massachusetts

EPA,

regarding the problem of climate change, it is not necessary to show that a problem will be entirely solved by the action being taken, nor that it is necessary to cure all ills before addressing those judged to be significant.

549 U.S. 497, 525 (2007).

Based on 2005 U.S. emissions of 105 tons, and global emissions of 2,100 tons from UNEP. Mercury emissions are discussed more fully in Section III.D.1 of this preamble.

At the time it published the December 2000 Finding, EPA identified certain technologies capable of significantly reducing Hg and other HAP emissions. Since then, additional technologies and improvements to those previously identified have become available. These technologies are also often effective at reducing significantly the emissions of other conventional pollutants such as SO

and PM, thereby conferring even greater health co-benefits. As today's notice discusses further, the reductions expected from the adopted final rule will produce substantially greater co-benefits to health and the environment than they will cost to affected companies. We further believe that these reductions can be achieved without significantly affecting the availability and cost of electricity to

consumers. In those instances in which such concerns do arise, the Federal government will work with companies to ensure a reliable and reasonably-priced supply of electricity. Moreover, in its assessment of the impacts of today's proposed rule on jobs and the economy, EPA finds that more jobs will be created in the air pollution control technology production field than may be lost as the result of compliance with these proposed rules.

A number of EGUs operating today were built in the 1950s and 1960s, using now-obsolete and inefficient technologies. Today, new units are far more efficient in their production of electricity, their use of fuel, and the relative quantities of pollution emitted. To the extent that some of the oldest, least efficient, least controlled units are retired by companies who elect not to invest in controlling them, assessments included in the docket to today's notice of proposed rulemaking indicate that there will be a sufficient supply of electricity from newer units. In fact, one consequence of today's proposed rule, if adopted as a final rule, will be that the market for electricity in the U.S. will be more level and no longer skewed in favor of the higher polluting units that were exempted from the CAA at its inception on Congress' assumption that their useful life was near an end. Thus, this proposed rule will require companies to make a decision—control HAP emissions from virtually uncontrolled sources or retire these sometimes 60 year old units and shift their emphasis to more efficient, cleaner modern methods of generation, including modern coal-fired generation.

For the reasons summarized above and discussed in detail in this document, the standards being proposed today will be effective at significantly reducing emissions of Hg and an array of other toxic pollutants from coal- and oil-fired EGUs. In addition, as a result of the HAP reductions and co-benefits of these rules, many premature deaths from exposure to air pollution will be avoided by the application of controls that are well-known, broadly applied, and available. To the extent that isolated issues remain concerning the availability of electricity in some more remote parts of the country, we believe that EPA has the ability to work with companies making good faith efforts to comply with the standards so that consumers in those areas are not adversely affected.

Consistent with the recently issued Executive Order (EO) 13563, “Improving Regulation and Regulatory Review,” we have estimated the cost and benefits of the proposed rule. The estimated net benefits of our proposed rule at a 3 percent discount rate are $48 to 130 billion or $42 to $120 billion at a 7 percent discount rate.

Summary of the Monetized Benefits, Social Costs, and Net Benefits for the Proposed Rule in 2016

[Millions of 2007$]

3% Discount rate

7% Discount rate

Total Monetized Benefits

$59,000 to $140,000

$53,000 to $130,000.

Hg-related Benefits

$4.1 to $5.9

$0.45 to $0.89.

-related Benefits

$570

$570.

2.5

-related Co-benefits

$58,000 to $140,000

$53,000 to $120,000.

Total Social Costs

$10,900

$10,900.

Net Benefits

$48,000 to $130,000

$42,000 to $130,000.

Non-monetized Benefits

Visibility in Class I areas.

Cardiovascular effects of Hg exposure.

Other health effects of Hg exposure.

Ecosystem effects.

Commercial and non-freshwater fish consumption.

All estimates are for 2016, and are rounded to two significant figures. The net present value of reduced CO

emissions are calculated differently than other benefits. The same discount rate used to discount the value of damages from future emissions (SCC at 5, 3, 2.5 percent) is used to calculate net present value of SCC for internal consistency. This table shows monetized CO

co-benefits at discount rates at 3 and 7 percent that were calculated using the global average SCC estimate at a 3 percent discount rate because the interagency workgroup on this topic deemed this marginal value to be the central value. In section 6.6 of the RIA we also report the monetized CO

co-benefits using discount rates of 5 percent (average), 2.5 percent (average), and 3 percent (95th percentile).

The total monetized benefits reflect the human health benefits associated with reducing exposure to MeHg, PM

2.5

, and ozone.

Based on an analysis of health effects due to recreational freshwater fish consumption.

The reduction in premature mortalities from account for over 90 percent of total monetized PM

2.5

benefits.

Social costs are estimated using the MultiMarket model, in order to estimate economic impacts of the proposal to industries outside the electric power sector. Details on the social cost estimates can be found in Chapter 9 and Appendix E of the RIA.

For more information on how EPA is addressing EO 13563, see the executive order discussion, later in the preamble.

B. Does this action apply to me?

The regulated categories and entities potentially affected by the proposed standards are shown in Table 1 of this preamble.

Table 1—Potentially Affected Regulated Categories and Entities

Category

NAICS code

Examples of potentially regulated entities

Industry

221112

Fossil fuel-fired electric utility steam generating units.

Federal government

221122

Fossil fuel-fired electric utility steam generating units owned by the Federal government.

State/local/tribal government

221122

Fossil fuel-fired electric utility steam generating units owned by municipalities.

921150

Fossil fuel-fired electric utility steam generating units in Indian country.

North American Industry Classification System.

Federal, State, or local government-owned and operated establishments are classified according to the activity in which they are engaged.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. To determine whether your facility, company, business, organization, etc., would be regulated by this action, you should examine the applicability criteria in 40 CFR 60.40, 60.40Da, or 60.40c or in 40 CFR 63.9982. If you have any questions regarding the applicability of this action to a particular entity, consult either the air permitting authority for the entity or your EPA regional representative as listed in 40 CFR 60.4 or 40 CFR 63.13 (General Provisions).

C. What should I consider as I prepare my comments to EPA?

Do not submit information containing CBI to EPA through

http://www.regulations.gov

or e-mail. Send or deliver information identified as CBI only to the following address: Roberto Morales, OAQPS Document Control Officer (C404-02), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, Attention: Docket ID EPA-HQ-OAR-2011-0044 (NSPS action) or Docket ID EPA-HQ-OAR-2009-0234 (NESHAP action). Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD-ROM that you mail to EPA, 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 claimed as CBI. In addition to one complete version of the comment that includes 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. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

D. Where can I get a copy of this document?

In addition to being available in the docket, an electronic copy of this proposed rule will also be available on the Worldwide Web (WWW) through the Technology Transfer Network (TTN). Following signature, a copy of the proposed rule will be posted on the TTN's policy and guidance page for newly proposed or promulgated rules at the following address:

http://www.epa.gov/ttn/oarpg/.

The TTN provides information and technology exchange in various areas of air pollution control.

E. When would a public hearing occur?

EPA will hold three public hearings on this proposal. The dates, times, and locations of the public hearings will be announced separately. If you would like to present oral testimony at one of the hearings, please notify Ms. Pamela Garrett, Sectors Policies and Programs Division (C504-03), U.S. EPA, Research Triangle Park, NC 27711, telephone number (919) 541-7966; e-mail:

garrett.pamela@epa.gov.

Persons wishing to provide testimony should notify Ms. Garrett at least 2 days in advance of the public hearings. For updates and additional information on the public hearings, please check EPA's Web site for this rulemaking,

http://www.epa.gov/ttn/atw/utility/utilitypg.html.

II. Background Information on the NESHAP

In 1990, Congress substantially rewrote provisions of the CAA addressing emissions of HAP from large and small stationary sources in the U.S. Collectively, these sources emit into the air millions of pounds of HAP each year, chemicals that are known to cause or are suspected of causing cancer, birth defects, reproduction problems, and other serious health effects. Many of the sources that emit air toxics are located in urban areas, which generally include predominantly low income, minority or otherwise vulnerable communities, where dense populations mean that large numbers of people may be exposed.

Since 1990, EPA has promulgated regulations covering over 50 industrial sectors, requiring the use of available control technology and other practices to reduce emissions. These standards have reduced emissions of HAP from American industry by more than 60 percent. HAP emissions from smaller sources such as dry cleaners and auto body shops have declined by 30 percent, also due to CAA standards. Greater reductions are expected as greater numbers of smaller sources adopt pollution prevention, efficiency, or install control technologies to comply with EPA emission standards. Emissions from the mobile source sector have also been addressed. Controls for fuels and vehicles are expected to reduce selected HAP from vehicles by more than 75 percent by 2020.

EGUs are the most significant source of HAP in the country that remains unaddressed by Congress's air toxics program. EGUs emit multiple HAP of concern and are by far the largest remaining source of Hg, which is one of the more highly toxic chemicals on Congress's list of HAP and which, once released, stays in the environment permanently. Coal- and oil-fired EGUs also emit HAP such as As, other metals and acid gases in amounts significantly higher than almost any other industrial sector. They are located in nearly every state, and emissions from their stacks affect people nearby as well as hundreds of miles away.

Congress provided a specific path for EPA to regulate HAP emissions from EGUs. It gave explicit instructions about scientific studies EPA needed to develop and then consider in determining whether it was “appropriate and necessary” to regulate HAP emissions from EGUs. Congress anticipated that EPA would complete the studies by 1994. In 2000, EPA found that it was indeed “appropriate and necessary” to regulate HAP emissions from EGUs under section 112. In the decade that has passed since EPA made that finding, EGUs have continued to emit Hg and other HAP, and there are still no national limits on the amount of Hg and other HAP that EGUs can release into the air. And, although some plants have installed available and effective control technologies that reduce these emissions, there is no requirement for EGUs to control for Hg and other HAP.

As our new analyses demonstrate, it remains both appropriate and necessary to set standards for coal- and oil-fired EGUs to protect public health and the environment from the adverse effects of HAP emissions from EGUs. The Agency's appropriate and necessary finding was correct in 2000, and it remains correct today. EPA proposes to set standards for coal- and oil-fired EGUs that will reduce emissions of Hg, Ni and other metal HAP, acid gas HAP, and other harmful HAP. These standards are based on available control technologies and other practices already used by the better-controlled and lower-emitting EGUs. They are achievable, we believe they can be implemented without disruption to the reliable provision of electricity, and will deliver health protection across the U.S.

In this section, we provide an overview of the relevant statutory, regulatory, and litigation background.

A. Statutory Background

Congress enacted section 112 to address HAP emissions from stationary sources. Section 112 contains provisions specific to EGUs, which we will address in this preamble, but we begin with a summary of the overall structure and purpose of the section 112 program.

Prior to the 1990 Amendments, the CAA required EPA to regulate HAP solely on the basis of risk to human

health. Legislative History of the CAA Amendments of 1990 (“Legislative History”), at 3174-75, 3346 (Comm. Print 1993). Congress was dissatisfied with the slow pace of exclusively risk-based regulation of HAP prior to 1990, however, and, as a result, substantially amended the CAA in 1990, setting forth a two-stage approach for regulating HAP emissions. Under the first stage, Congress directed EPA to issue technology-based emission standards for listed source categories. CAA sections 112 (c)-(d). In the second stage, which occurs “within eight years” of the imposition of the technology-based standards, EPA must consider whether residual risks remain after imposition of the MACT standards that warrant more stringent standards to protect human health or to prevent an adverse environmental effect. CAA section 112(f)(2)(A).

In addition to adopting this two-phased approach to standard-setting, Congress included a series of rigorous deadlines for EPA, including deadlines for listing categories and issuing emission standards for such categories.

See, e.g.,

CAA section 112(e)(1). Thus, in substantially amending CAA section 112 in 1990, Congress sought prompt and permanent reductions of HAP emissions from stationary sources—first through technology-based standards, and then further, as necessary, through risk-based standards designed to protect human health and the environment.

The criteria for regulation differ in section 112 depending on whether the source is a major source or an area source. A “major source” is any stationary source

or group of stationary sources at a single location and under common control that emits or has the potential to emit 10 tons or more per year of any HAP or 25 tons or more per year of any combination of HAP.

See

CAA 112(a)(1). An “area source” is any stationary source of HAP that is not a “major source.”

See

CAA 112(a)(2). For major sources, EPA must list a category under section 112(c)(1) if at least one stationary source in the category meets the definition of a major source.

For area sources, EPA must list if: (1) EPA determines that the category of area sources presents a threat of adverse effects to human health or the environment that warrants regulation under CAA section 112; or (2) the category of area sources falls within the purview of CAA section 112(k)(3)(B) (the Urban Area Source Strategy).

See

CAA section 112(c)(3).

A “stationary source” of HAP is any building, structure, facility or installation that emits or may emit any air pollutant. See CAA Section 112(a)(3).

Congress required EPA to publish a list of categories and subcategories of major sources and area sources by November 15, 1991. See CAA 112(c)(1) & (c)(3). EPA published the initial list on July 16, 1992. See 57 FR 31576, July 16, 1992. EPA did not include EGUs on the initial section 112(c) list because Congress required EPA to conduct and consider the results of the study required by section 112(n)(1)(A) before regulating these units. At the time of the initial listing, EPA had not completed the study required by section 112(n)(1)(A).

Congress established a specific structure for determining whether to regulate EGUs under section 112.

Specifically, Congress enacted CAA section 112(n)(1).

“Electric utility steam generating unit” is defined as any “fossil fuel fired combustion unit of more than 25 megawatts that serves a generator that produces electricity for sale.” See CAA 112(a)(8).

In section 112(n)(1)(A), EPA is directed to conduct a study to evaluate the hazards to public health reasonably anticipated to occur as the result of HAP emissions from EGUs after imposition of the requirements of the CAA, and to report the results of such study to Congress by November 15, 1993 (Utility Study Report to Congress;

the “Utility Study”). We discuss this study further below in conjunction with the other studies Congress required be conducted with respect to EGUs under section 112(n)(1). The last sentence of section 112(n)(1)(A) provides that EPA shall regulate EGUs under CAA section 112 “if the Administrator finds such regulation is appropriate and necessary, after considering the results of the [Utility Study] * * *” Thus, section 112(n)(1)(A) governs how the Administrator decides whether to list EGUs for regulation under section 112.

See New Jersey,

517 F.3d at 582 (“Section 112(n)(1) governs how the Administrator decides whether to list EGUs; it says nothing about delisting EGUs.”).

US EPA. Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units —Final Report to Congress. EPA-453/R-98-004a. February 1998.

Once a source category is listed pursuant to section 112(c), the next step is for EPA to establish technology-based emission standards under section 112(d). Under section 112(d), EPA must establish emission standards for major sources that “require the maximum degree of reduction in emissions of the HAP subject to this section” that EPA determines is achievable taking into account certain statutory factors. These are referred to as “maximum achievable control technology” or “MACT” standards. The MACT standards for existing sources must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources in the category (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources.

See

CAA section 112(d)(3)(A) and (B). This level of minimum stringency is referred to as the MACT floor, and EPA cannot consider cost in setting the floor. For new sources, MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar source.

See

CAA section 112(d)(3). EPA also must consider more stringent “beyond-the-floor” control options. When considering beyond-the-floor options, EPA must consider not only the maximum degree of reduction in emissions of HAP, but must take into account costs, energy, and nonair quality health and environmental impacts when doing so.

See Cement Kiln Recycling Coal.

EPA,

255 F.3d 855, 857-58 (D.C. Cir. 2001).

CAA section 112(d)(4) authorizes EPA to set a health-based standard for a limited set of HAP for which a health threshold has been established, and that standard must provide for “an ample margin for safety.” 42 U.S.C. 7412(d)(4). As these standards are potentially less stringent than MACT standards, the Agency must have detailed information on HAP emissions from the subject sources and sources located near the subject sources before exercising its discretion to set such standards.

For area sources, section 112(d)(5) authorizes EPA to issues standards or requirements that provide for the use of generally available control technologies (GACT) or management practices in lieu of promulgating standards pursuant to sections 112(d)(2) and (3).

As noted above, Congress required that various reports concerning EGUs be completed. The first report, the Utility Study, required EPA to evaluate the hazards to public health reasonably anticipated to occur as the result of HAP emissions from EGUs after imposition of the requirements of the CAA. This report was required by November 15, 1993. The second report, due on November 15, 1994, directed EPA to “conduct a study of mercury emissions from [EGUs], municipal waste combustion units, and other sources, including area sources.”

See

CAA section 112(n)(1)(B). In conducting the Mercury study Congress directed EPA to “consider the rate and mass of emissions, the health and environmental effects of such emissions, technologies which are available to control such emissions, and the costs of such technologies.”

Id.

EPA completed both of these reports by 1998.

The last required report was to be completed by the National Institute of Environmental Health Sciences (NIEHS) and submitted to Congress by November 15, 1993. CAA section 112(n)(1)(C) directed NIEHS to conduct “a study to determine the threshold level of Hg exposure below which adverse human health effects are not expected to occur.” In conducting this study, NIEHS was to determine “a threshold for mercury concentrations in the tissue of fish which may be consumed (including consumption by sensitive populations) without adverse effects to public health.” Id. NIEHS submitted this Report to Congress in August, 1995.

In addition, Congress, in conference report language associated with EPA's fiscal year 1999 appropriations, directed EPA to fund the National Academy of Sciences (NAS) to perform an independent evaluation of the available data related to the health impacts of MeHg (“Toxicological Effects of Methylmercury,” hereinafter, NAS Study or MeHg Study).

H.R. Conf. Rep. No. 105-769, at 281-282 (1998). Specifically, NAS was tasked with advising EPA as to the appropriate reference dose (RfD) for MeHg, which is the amount of a chemical which, when ingested daily over a lifetime, is anticipated to be without adverse health effects to humans, including sensitive subpopulations. 65 FR 79826. In that same conference report, Congress indicated that EPA should not make the appropriate and necessary regulatory determination for Hg emissions until EPA had reviewed the results of the NAS Study.

See

H.R. Conf. Rep. No. 105-769, at 281-282 (1998).

National Research Council (NAS). 2000. Toxicological Effects of Methylmercury. Committee on the Toxicological Effects of Methylmercury, Board on Environmental Studies and Toxicology, National Research Council. Many of the peer-reviewed articles cited in this section are publications originally cited in the NAS report.

The NAS Study evaluated the same issues as those required to be considered under section 112(n)(1)(C). The NAS Study was completed 5 years after the NIEHS Study, and, thus, considered additional information not available to NIEHS. Because Congress required that the same issues be addressed in both the NAS and NIEHS Studies and the NAS Study was issued after the NIEHS study, we discuss, for purposes of this document, the content of the NAS Study, as opposed to the NIEHS Study.

B. Regulatory and Litigation Background

EPA conducted the studies required by section 112(n)(1) concerning utility HAP emissions. Prior to issuance of the Mercury Study, EPA engaged in two extensive external peer reviews of the document. Although EPA missed the statutory deadline for completing the studies, the Mercury Study and the Utility Study were complete by 1998. The NIEHS study was completed in 1995, and the NAS Study was completed in 2000.

In December 2000, after considering public input, the studies required by section 112(n)(1) and other relevant information, including Hg emissions data from EGUs, EPA determined that it was appropriate and necessary to regulate EGUs under CAA section 112. Based on that determination, the Agency listed such units for regulation under section 112(c).

Pursuant to a settlement agreement, the deadline for issuing emission standards was March 15, 2005. However, instead of issuing emission standards pursuant to section 112(d), on March 15, 2005, EPA delisted EGUs, finding that it was neither appropriate nor necessary to regulate such units under section 112. That attempt to delist was subsequently invalidated by the DC Circuit Court.

1. Studies Related to HAP Emissions From EGUs

a. The Utility Study

EPA issued the Utility Study in February 1998, over 4 years after the statutory deadline. The Utility Study included numerous analyses. EPA first collected HAP emissions test data from 52 EGUs, including a range of coal-, oil-, and natural gas-fired units, and the test data along with facility specific information were used to estimate HAP emissions from all 684 utility facilities. EPA determined that 67 HAP were emitted from EGUs. In addition, the study evaluated HAP emissions based on two scenarios: (1) 1990 base year; and (2) 2010 projected emissions. The 2010 scenario was selected to meet the section 112(n)(1)(A) mandate to evaluate hazards “after imposition of the requirements of the Act.” EPA also considered potential control strategies for the identified HAP consistent with section 112(n)(1)(A).

EPA evaluated exposures, hazards, and risks due to HAP emissions from coal-, oil-, and natural gas-fired EGUs. EPA conducted a screening level assessment of all 67 HAP to prioritize the HAP for further analysis. A total of 14 HAP were identified as priority HAP that would be further assessed. Twelve HAP (As, beryllium (Be), Cd, Cr, manganese (Mn), Ni, HCl, HF, acrolein, dioxins, formaldehyde, and radionuclides) were identified as a priority for further assessment based on inhalation exposure and risk. Six HAP (Hg, radionuclides, As, Cd, Pb, and dioxins) were considered a priority for multipathway assessment of exposure and risk.

Based on the inhalation estimates for the priority HAP, EPA determined that As and Cr emissions from coal-fired EGUs and Ni emissions from oil-fired EGUs contributed most to the potential cancer related inhalation risks, but those risks were not high. The non-cancer risk assessment due to inhalation exposure indicated exposures were well below the reference levels.

The Agency also conducted multipathway assessments for the six HAP identified above. Based on these analyses, EPA determined that Hg from coal-fired EGUs was the HAP of greatest potential concern. In addition, the screening multipathway assessments for dioxins and As suggested that these two HAP were of potential for multipathway risk.

In addition to the 1990 analysis, EPA also estimated emissions and inhalation risks for the year 2010. HAP emissions from coal-fired utilities were predicted to increase by 10 to 30 percent by the year 2010. Predicted changes included the installation of scrubbers for a small number of facilities, the closing of a few facilities, and an increase in fuel consumption of other facilities. For oil-fired plants, emissions and inhalation risks were estimated to decrease by 30 to 50 percent by the year 2010, primarily due to projected reductions in use of oil for electricity generation. Multipathway risks for 2010 were not assessed.

In estimating future emissions from EGUs, EPA primarily evaluated the effect of implementation of the Acid Rain Program (ARP) on HAP emissions from EGUs. The 2010 scenario also included estimated changes in emissions resulting from projected trends in fuel choices and power demands.

Table 2 of this preamble presents estimated emissions for a subset of priority HAP for 1990 and 2010.

Table 2—Nationwide Emissions for Six Priority HAP, tpy

HAP

Coal

1990

2010

Oil

1990

2010

Natural gas

1990

2010

Arsenic

0.15

0.25

Chromium

4.7

2.4

Mercury

0.25

0.13

0.0015

0.024

Nickel

390

200

2.2

3.5

Hydrogen chloride

143,000

155,000

2,900

1,500

Hydrogen fluoride

20,000

26,000

140

Numerous potential alternative control strategies for reducing HAP emissions from EGUs were identified. These included pre-combustion controls (

e.g.,

fuel switching, coal cleaning), post combustion controls (

e.g.,

PM controls, SO

controls), and improving efficiency in supply or demand. For example, coal cleaning tends to remove at least some of all the trace metals. EPA also concluded that PM controls tend to effectively remove the trace metals (excluding Hg). The Utility Study also found that flue gas desulfurization (FGD) units were less effective at removing trace metals and exhibited more variability in removal of those metals than PM control, but FGD were more effective at reducing acid gas HAP.

b. The Mercury Study

EPA issued the Mercury Study in December 1997, 3 years after the statutory deadline. The Mercury Study assessed the magnitude of U.S. Hg emissions by source, the health and environmental implications of those emissions, and the availability and cost of control technologies.

According to the Mercury Study, Hg cycles in the environment as a result of natural and human (anthropogenic) activities. Most of the Hg in the atmosphere is elemental Hg vapor, which circulates in the atmosphere for up to a year, and, hence, can be widely dispersed and transported thousands of miles from likely sources of emission. The Mercury Study also found that most of the Hg in water, soil, sediments, or plants and animals is in the form of inorganic Hg salts and organic forms of Hg (

e.g.,

MeHg). The inorganic form of Hg, when either bound to airborne particles or in a gaseous form, is readily removed from the atmosphere by precipitation and is also dry deposited. Wet deposition is the primary mechanism for transporting Hg from the atmosphere to surface waters and land. Even after it deposits, Hg commonly is emitted back to the atmosphere either as a gas or associated with particles, to be re-deposited elsewhere.

The Mercury Study estimated that in 1994-1995, anthropogenic U.S. Hg emissions were about 158 tons annually. Roughly 87 percent of those emissions were from combustion sources, including waste and fossil fuel combustion. According to the Mercury Study, current anthropogenic emissions were only one part of the Hg cycle. The Mercury Study noted that current releases from human activities were adding to the Hg reservoirs that already exist in land, water, and air, both naturally and as a result of prior human activities. The Mercury Study concluded that the flux of Hg from the atmosphere to land or water at any one location is comprised of contributions from the natural global cycle, including re-emissions from the oceans, international sources, regional sources, and local sources.

The Mercury Study further described a computer simulation of long-range transport of Hg, which suggested that about one-third (approximately 52 tons) of U.S. anthropogenic emissions are deposited, through wet and dry deposition, within the lower 48 states. The remaining two-thirds (approximately 107 tons) was estimated to be transported outside of U.S. borders where it would diffuse into the global reservoir. The computer simulation further suggested that another 35 tons of Hg from the global reservoir outside the U.S. was deposited annually in the U.S. for a total deposition in the U.S. of roughly 87 tons per year (tpy).

The Mercury Study also found that fish consumption dominates the pathway for human and wildlife exposure to MeHg and that there was a plausible link between anthropogenic releases of Hg from industrial and combustion sources in the U.S. and MeHg in fish. In the Mercury Study, EPA explained that, given the current scientific understanding of the environmental fate and transport of this element, it was not possible to quantify how much of the MeHg in fish consumed by the U.S. population results from U.S. anthropogenic emissions, as compared to other sources of Hg (such as natural sources and re-emissions from the global pool).

The Mercury Study noted that those who regularly and frequently consume large amounts of fish—either marine species that typically have much higher levels of MeHg than other species, or freshwater fish that have been affected by Hg pollution—are more highly exposed. Because the developing fetus may be the most sensitive to the effects from MeHg, women of child-bearing age were the population of greatest interest. EPA concluded in the Mercury Study that approximately 7 percent of women of child-bearing age (

i.e.,

between the ages of 15 and 44) were exposed to MeHg at levels exceeding the RfD.

Finally, the Mercury Study concluded that piscivorous (fish-eating) birds and mammals were more highly exposed to Hg than any other known component of aquatic ecosystems, and that adverse effects of Hg on fish, birds and mammals include death, reduced reproductive success, impaired growth and development, and behavioral abnormalities. The Mercury Study also evaluated Hg emissions control technologies and the costs of such technologies.

c. The NAS Methylmercury Study

In the appropriations report for EPA's fiscal 1999 funding, Congress directed EPA to fund the NAS to perform an independent study on the toxicological effects of MeHg and to prepare recommendations on the establishment of a scientifically appropriate MeHg exposure RfD. In response, EPA contracted with NAS, which conducted an 18-month study of the available data on the health effects of MeHg and reported its findings to EPA in July 2000.

The EPA included four charges to NAS: (1) Evaluate the body of evidence that led to EPA's current RfD for MeHg, and on the basis of available human epidemiological and animal toxicity data, determine whether the critical study, end point of toxicity, and uncertainty factors used by EPA in the derivation of the RfD for MeHg are scientifically appropriate, including

consideration of sensitive populations; (2) evaluate any new data not considered in the Mercury Study that could affect the adequacy of EPA's MeHg RfD for protecting human health; (3) consider exposures in the environment relevant to evaluation of likely human exposures (especially to sensitive subpopulations and especially from consumption of fish that contain MeHg), and include in the evaluation a focus on those elements of exposure relevant to the establishment of an appropriate RfD; and (4) identify data gaps and make recommendations for future research.

The NAS held both public and closed sessions wherein they evaluated data and presentations from government agencies, trade organizations, public interest groups, and concerned citizens. The NAS also evaluated new findings that had emerged since the development of EPA's 1995 RfD and met with the investigators of major ongoing epidemiological studies.

The NAS Study concluded that the value of EPA's 1995 RfD for MeHg, 0.1 micrograms per kilogram (µg/kg) per day, was a scientifically appropriate level for the protection of public health. The NAS Study further concluded that data from both human and animal studies indicated that the developing nervous system was a sensitive target organ for low-dose MeHg exposure. The NAS Study indicated that there was evidence that exposure to MeHg in humans and animals can have adverse effects on both the developing and adult cardiovascular system. Some of the studies observed adverse cardiovascular effects at or below MeHg exposure levels associated with neurodevelopmental effects. The weight of evidence for carcinogenicity of MeHg was inconclusive. There was also evidence from animal studies that the immune and reproductive systems are sensitive targets for MeHg toxicity.

According to the NAS Study, the estimates of MeHg exposures in the U.S. population indicated that the risk of adverse effects from then-current MeHg exposures in the majority of the population was low. However, the NAS Study concluded that individuals with high MeHg exposures from frequent fish consumption might have little or no margin of safety (

i.e.,

exposures of high-end consumers are close to those with observable adverse effects). The NAS Study also noted that the population at highest risk was the children of women who consumed large amounts of fish and seafood during pregnancy. The NAS Study further concluded that the impact on that population was likely to be sufficient to result in an increase in the number of children who struggle to keep up in school and might require remedial classes or special education.

2. EPA's December 2000 Appropriate and Necessary Finding

On December 20, 2000, EPA issued a finding pursuant to CAA section 112(n)(1)(A) that it was appropriate and necessary to regulate coal- and oil-fired EGUs under section 112 and added such units to the list of source categories subject to regulation under section 112(d). In making that finding, EPA considered the Utility Study, the Mercury Study, the NAS Study, and certain additional information, including information about Hg emissions from coal-fired EGUs that EPA obtained pursuant to an information collection request (ICR) under the authority of section 114 of the CAA. 65 FR 79826-27. EPA collected data on the Hg content of coal from all coal-fired EGUs for the calendar year 1999 and Hg emissions stack test data for certain coal-fired EGUs. 65 FR 79826. EPA also solicited data from the public through a February 29, 2000, notice (65 FR 10783). The public had an opportunity to provide their views on what the section 112(n)(1)(A) appropriate and necessary regulatory finding should be at a public meeting in Chicago, Illinois, on June 13, 2000 (65 FR 18,992). 65 FR 79826.

In the December 2000 notice, EPA explained that it evaluated EGUs based on the type of fossil fuel combusted (

i.e.,

coal, oil, and natural gas). The December 2000 Finding focused primarily on Hg emissions from coal-fired EGUs. Mercury was determined to be the HAP of greatest concern in the Utility Study. In evaluating Hg emissions from coal-fired EGUs, EPA stated that the quality of the Hg data available in 2000 was considerably better than the data available for the Utility Study because of the results of the 1999 ICR. The new data also corroborated the Hg emissions estimates in the study. 65 FR 79828. In the finding, EPA explained that Hg is highly toxic and persistent and that it bioaccumulates in the food chain; that Hg air emissions from all sources, including EGUs, deposit on the land where the Hg may transform into MeHg, which is the primary type of Hg that accumulates in fish tissue; and that eating Hg contaminated fish was the primary route of exposure for humans. 65 FR 79827. The potential hazard of most concern was determined to be consumption by subsistence fish-eating populations and women of childbearing age because of the adverse effects that Hg poses to the developing fetus. 65 FR 79827. Finally, EPA noted that approximately 7 percent of women of child bearing age were exposed to levels of MeHg that exceeded the RfD. 65 FR 79827.

EPA further estimated that about 60 percent of the total Hg deposited in the U.S. came from anthropogenic air emissions originating in the U.S. and that EGUs contributed approximately 30 percent of those anthropogenic air emissions. 65 FR 79827. Based on the record before the Agency at the time, EPA determined that there was a plausible link between Hg emissions from EGUs and MeHg in fish and that Hg emissions from EGUs were a threat to public health and the environment. 65 FR 79827.

In discussing the non-Hg HAP from coal- and oil-fired EGUs, EPA stated that HAP metals such as As, Cr, Ni, and Cd are of potential concern for carcinogenic effects. 65 FR 79827. EPA acknowledged that the risk assessments conducted for these HAP indicated that cancer risks were not high, but the Agency could not conclude the potential concern for public health was eliminated for those metals. 65 FR 79827. EPA further stated that dioxins, HCl, and HF were of potential concern and could be evaluated further during the regulatory development process. 65 FR 79827. EPA also concluded that the remaining HAP evaluated in the Utility Study did not appear to be a public health concern, but the Agency noted that there were limited data and uncertainties associated with this conclusion, and we stated that future data collection efforts could identify additional HAP of potential concern. 65 FR 79827.

EPA also explained that, consistent with Congress's direction in section 112(n)(1)(A), we considered the alternative control strategies available to control the HAP emissions that may warrant control. We noted that currently available controls for criteria pollutants would also be effective at controlling the HAP emissions from EGUs. 65 FR 79828.

EPA then made nine specific conclusions based on the information in the record, some of which are summarized above. 65 FR 79829-30. Based on those conclusions, EPA found that it was “appropriate” to regulate HAP emissions from coal- and oil-fired EGUs because EGUs “are the largest domestic source of Hg emissions, and Hg in the environment presents significant hazards to public health and the environment.” 65 FR 79830. EPA noted that the NAS Study confirmed EPA's own research concluding that “mercury in the environment presents a significant hazard to public health.” 65

FR 79830. EPA explained that it was appropriate to regulate HAP emissions from coal- and oil-fired units because it had identified certain control options that, it anticipated, would effectively reduce HAP from such units. 65 FR 79830. In discussing its findings, EPA also noted that uncertainties remained concerning the extent of the public health impact from HAP emissions from oil-fired units. 65 FR 79830.

Once EPA determined that it was “appropriate” to regulate coal- and oil-fired EGUs under CAA section 112, EPA next concluded that it was also “necessary” to regulate HAP emissions from such units under section 112 “because the implementation of other requirements under the CAA will not adequately address the serious public health and environmental hazards arising from such emissions identified in the Utility RTC and confirmed by the NAS Study, and which section 112 is intended to address.” 65 FR 79830.

For natural gas-fired EGUs, EPA found that regulation of HAP emissions “is not appropriate or necessary because the impacts due to HAP emissions from such units are negligible based on the results of the study documented in the utility RTC.” 65 FR 79831.

In light of the positive appropriate and necessary determination, EPA in December 2000 listed coal- and oil-fired EGUs on the section 112(c) source category list. 65 FR 79831.

3. The 2005 Action

On March 29, 2005, EPA issued the Section 112(n) Revision Rule (“2005 Action”) that has since been vacated by the DC Circuit Court. In that rule, EPA reversed the December 2000 Finding and concluded that it was neither appropriate nor necessary to regulate coal- and oil-fired EGUs under section 112 and delisted such units from the section 112(c) source category list. 70 FR 15994. EPA took the position that the December 2000 Finding lacked foundation and that new information confirmed that it was not appropriate or necessary to regulate coal- and oil-fired EGUs under CAA section 112.

In the final rule, EPA provided a detailed interpretation of section 112(n)(1)(A), including the terms “appropriate” and “necessary,” as those terms relate to the regulation of EGUs under section 112. In interpreting the statute, EPA recognized that section 112(n)(1)(A) provided no explicit guidance for determining whether regulation of EGUs is appropriate and necessary. As such, EPA concluded that Congress' direction on the Utility Study provided the only guidance about the substance of the appropriate and necessary finding. Accordingly, EPA extrapolated from Congress' description of the Utility Study when interpreting the terms appropriate and necessary.

Among other things, the Agency interpreted the focus on public health in the Utility Study as precluding EPA from considering environmental impacts. 70 FR 15998. EPA also looked at Congress' focus on EGU emissions in the Study and took the position that EPA could only consider hazards to public health that could be traced directly to HAP emissions from EGUs in assessing whether it was appropriate to regulate. EPA declined to consider the potential adverse public health impacts that may occur as the result of the combination of EGU HAP emissions and HAP emissions from other sources. 70 FR 15998.

In making the determination as to whether it was appropriate to regulate, EPA analyzed whether the level of HAP emissions from EGUs remaining after imposition of the requirements of the CAA would result in a hazard to public health. EPA concluded that if the HAP emissions remaining after imposition of the requirements of the CAA do not pose a hazard to public health, then regulation under section 112 is not appropriate. EPA also maintained that even if it identified a hazard to public health, regulation may still not be “appropriate” based on other relevant factors, such as the cost effectiveness of regulation under section 112. 70 FR 15600.

In the 2005 Action, EPA interpreted the term “necessary” to mean “that it is necessary to regulate EGUs under section 112 only if there are no other authorities available under the CAA that would, if implemented, effectively address the remaining HAP emissions from EGUs.” 70 FR 16001.

Applying these interpretations, the Agency stated that it was neither appropriate nor necessary to regulate HAP emissions from EGUs. The Agency took the position that the December 2000 appropriate finding lacked foundation because the finding was overbroad to the extent that it relied on environmental effects. 70 FR 16002. The EPA next stated that the appropriate determination in the December 2000 Finding lacked foundation because EPA did not fully consider the Hg reductions that would result after imposition of the requirements of the CAA and that new information showed that the level of Hg emissions from EGUs remaining after imposition of the requirements of the CAA do not pose a hazard to public health. 70 FR 16003-4. Specifically, EPA pointed to the promulgation of the Clean Air Interstate Rule (CAIR), issued pursuant to CAA section 110(a)(2)(D), and the Clean Air Mercury Rule (CAMR),

issued pursuant to section 111, and, based on modeling, determined that CAIR, and independently CAMR, could be expected to reduce Hg emissions to levels that would not cause a hazard to public health. Therefore, EPA concluded that it was not appropriate to regulate EGUs under section 112. We note that CAMR was vacated by the D.C. Circuit Court in

New Jersey

EPA,

and that CAIR was remanded to the Agency in

North Carolina

EPA,

531 F.3d 896,

modified on reh'g,

550 F.3d 1176 (DC Cir. 2008).

On May 18, 2005, EPA issued the Clean Air Mercury Rule (CAMR). 70 FR 28606. That rule established standards of performance for emissions of mercury from new and existing coal-fired EGUs pursuant to CAA section 111.

As to the necessary finding, EPA took the position that the December 2000 Finding was in error because EPA did not, at the time, examine whether there were any CAA provisions other than section 112 that, if implemented, would address any identified hazards to public health from HAP emissions from EGUs. 70 FR 16004. Specifically, EPA stated that the error existed because EPA did not consider CAA sections 110(a)(2)(D) and 111 and that, considering actions under these sections, hazard to public health from EGUs would be reduced. 70 FR 16005.

EPA also determined that it was not appropriate and necessary to regulate coal-fired EGUs on the basis of non-Hg HAP emission or oil-fired EGUs on the basis of Ni and non-Ni HAP. 70 FR 16007.

4. Litigation History

Shortly after issuance of the December 2000 Finding, an industry group challenged that finding in the DC Circuit Court.

UARG

EPA,

2001 WL 936363, No. 01-1074 (DC Cir. July 26, 2001). The DC Circuit Court dismissed the lawsuit holding that it did not have jurisdiction because section 112(e)(4) provides, in pertinent part, that “no action of the Administrator * * * listing a source category or subcategory under subsection (c) of this section

shall be a final agency action subject to judicial review,

except that any such action may be reviewed under section 7607 of (the CAA) when the Administrator issues emission standards for such pollutant or category.” (

emphasis added

)

Environmental groups, States, and tribes challenged the 2005 Action and CAMR. Among other things, the environmental and state petitioners argued that EPA could not remove EGUs

from the section 112(c) source category list without following the requirements of section 112(c)(9).

On February 8, 2008, the DC Circuit Court vacated both the 2005 Action and CAMR. The DC Circuit Court held that EPA failed to comply with the requirements of section 112(c)(9) for delisting source categories. Specifically, the DC Circuit Court held that section 112(c)(9) applies to the removal of “any source category” from the section 112(c) list, including EGUs. The DC Circuit Court rejected the argument that EPA has the inherent authority to correct its mistakes, finding that, by enacting section 112(c)(9), Congress limited EPA's discretion to reverse itself and remove source categories from the section 112(c) list. The DC Circuit Court found that EPA's contrary position would “nullify § 112(c)(9) altogether.”

New Jersey

, 517 F.3d at 583. The DC Circuit Court did not reach the merits of petitioners' arguments on CAMR, but vacated CAMR for existing sources because coal-fired EGUs were listed sources under section 112. The DC Circuit Court reasoned that even under EPA's own interpretation of the CAA, regulation of existing sources' Hg emissions under section 111 was prohibited if those sources were a listed source category under section 112.

The DC Circuit Court vacated and remanded CAMR for new sources because it concluded that the assumptions EPA made when issuing CAMR for new sources were no longer accurate (

i.e.,

that there would be no section 112 regulation of EGUs and that the section 111 standards would be accompanied by standards for existing sources).

Id.

at 583-84. Thus, CAMR and the 2005 appropriate and necessary finding became null and void.

In CAMR and the 2005 Action, EPA interpreted section 111(d) of the Act as prohibiting the Agency from establishing an existing source standard of performance under section 111(d) for any HAP emitted from a particular source category, if the source category is regulated under section 112.

On December 18, 2008, several environmental and public health organizations (“Plaintiffs”)

filed a complaint in the DC District Court (Civ. No. 1:08-cv-02198 (RMC)) alleging that the Agency had failed to perform a nondiscretionary duty under CAA section 304(a)(2), by failing to promulgate final section 112(d) standards for HAP from coal- and oil-fired EGUs by the statutorily mandated deadline, December 20, 2002, 2 years after such sources were listed under section 112(c). EPA settled that litigation. The consent decree resolving the case requires EPA to sign a notice of proposed rulemaking setting forth EPA's proposed section 112(d) emission standards for coal- and oil-fired EGUs by March 16, 2011, and a notice of final rulemaking by November 16, 2011.

American Nurses Association, Chesapeake Bay Foundation, Inc., Conservation Law Foundation, Environment America, Environmental Defense Fund, Izaak Walton League of America, Natural Resources Council of Maine, Natural Resources Defense Council, Physicians for Social Responsibility, Sierra Club, The Ohio Environmental Council, and Waterkeeper Alliance, Inc.

III. Appropriate and Necessary Finding

As required by the CAA, we determined in December 2000, and confirm that finding here, that it is appropriate to regulate emissions of Hg and other HAP from EGUs because manmade emissions of those pollutants pose hazards to public health and the environment, and EGUs are the largest or among the largest contributors of many of those HAP. It is necessary to do so for a variety of reasons, including that hazards to public health and the environment from EGUs remain after imposition of the requirements of the CAA.

In this section, we address the Agency's determination that it is appropriate and necessary to regulate coal- and oil-fired EGUs under CAA section 112. We first provide our interpretation of the critical terms in CAA section 112(n)(1). As shown below, these interpretations are wholly consistent with the CAA and the December 2000 Finding. We then demonstrate that the December 2000 Finding was valid at the time it was made based on the information available to the Agency at that time. Finally, we explain that, although not required, we recently conducted additional technical analyses given that several years have passed since the December 2000 Finding was issued. Those analyses include both a quantitative and qualitative assessment of the hazards to public health and a qualitative analysis of hazards to the environment associated with Hg and non-Hg HAP from EGUs. The analyses confirm that it remains appropriate and necessary today to regulate EGUs under CAA section 112. We also explain why these analyses and the other information currently before the Agency confirm that regulation of EGUs under section 112 is appropriate and necessary. Accordingly, such units are properly listed pursuant to section 112(c).

A. Regulating EGUs Under CAA Section 112

CAA section 112(n)(1)(A) requires the Agency to regulate EGUs under section 112 “if the Administrator finds such regulation is

appropriate

and

necessary

after considering the results of the [Utility Study].” (

emphasis added

). Congress did not define the phrase “appropriate and necessary” in section 112(n)(1)(A). Rather, Congress expressly delegated to the Agency the authority to interpret and apply those terms.

See Chevron U.S.A. Inc.

Natural Resources Defense Council, Inc.,

467 U.S. 837, 843-44 (1984) (the Agency's interpretation of statutory terms is entitled to considerable deference as long as it is a reasonable reading of the statute).

Courts have interpreted the terms “appropriate” and “necessary” in other provisions of the CAA and other statutes, and concluded that those terms convey upon the Agency a wide degree of discretion.

See, e.g., National Association of Clean Air Act Agencies

EPA,

489 F.3d 1221, 1229 (DC Cir. 2007) (finding “both explicit and extraordinarily broad” the Administrator's authority under CAA section 231(a)(3) to “issue regulations with such modifications

as he deems appropriate.”

) (

emphasis in original

);

see

also

Cellular Telecommunications & Internet Association, et al.

FCC,

330 F.3d 502, 510 (DC Cir. 2003), (finding that “[c]ourts have frequently interpreted the word `necessary' to mean less than absolutely essential, and have explicitly found that a measure may be `necessary' even though acceptable alternatives have not been exhausted.” (quoting

Natural Res. Def. Council

Thomas,

838 F.2d 1224, 1236 (DC Cir. 1998) (internal quotation marks omitted)).

We evaluate the terms “appropriate” and “necessary” within the statutory context in which they appear to determine the meaning of the words.

See Cellular Telecommunications,

330 F.3d at 510 (finding that “it is crucial to understand the context in which the word [necessary] is used in order to comprehend its meaning.”) (citations omitted). In this case, we look for guidance in section 112 generally, and focus specifically on section 112(n)(1), which addresses EGUs.

1. Statutory Framework for Evaluating EGUs

As explained above, Congress, concerned by the slow pace of EPA's regulation of HAP, “altered section 112 by eliminating much of EPA's discretion in the process.”

New Jersey,

517 F.3d at 578 (citations omitted). We describe above the two-phased approach to standard setting. Also, relevant, however, is that Congress set very strict deadlines for listing source categories and issuing emission standards for such

categories.

See e.g.,

Section 112(c)(6), 112(e)(1);

New Jersey,

517 F.3d at 578 (noting that “EPA was required to list and to regulate, on a prioritized schedule” all categories and subcategories of major and area sources). Thus, in substantially amending section 112 of the CAA in 1990, Congress sought prompt and permanent reductions of HAP emissions from stationary sources—first through technology-based standards, and then further, as necessary, through risk-based standards designed to protect human health and the environment.

Congress' focus on protecting public health and the environment from EGU HAP emissions is reflected in section 112(n)(1), titled “[e]lectric utility steam generating units.” That section directs EPA to evaluate HAP emissions from EGUs. In addition to directing EPA to regulate EGUs under section 112 if it determines that it is appropriate and necessary to do so, section 112(n)(1) requires the completion of three studies related to HAP emissions from EGUs. Those studies include: (1) The Utility Study pursuant to section (n)(1)(A); (2) the Mercury Study pursuant to section (n)(1)(B); and (3) the NIEHS Study (NAS Study) pursuant to section 112(n)(1)(C).

As explained above, the NAS Study studied the same issues Congress wanted addressed pursuant to section 112(n)(1)(C) and, because it was conducted five years after the NIEHS study, it was a more comprehensive study accounting for new information not available to NIEHS. Congress directed both studies and wanted EPA to consider the NAS Study before issuing the appropriate and necessary finding so we are reasonably focusing our discussion on the content of the later study.

These studies are described above, in detail. In summary, for the Utility Study, Congress required EPA to evaluate the hazards to public health that are reasonably anticipated to occur as the result of EGU emissions following imposition of the requirements of the CAA. Congress also directed EPA to identify alternative control strategies for those HAP that may warrant regulation under section 112.

The Mercury Study required by section 112(n)(1)(B) is both broader and narrower in scope, as compared to the Utility Study. For example, the Mercury Study is narrower in scope, in that it focuses solely on the impacts from Hg emissions, as opposed to all HAP. The Mercury Study is broader in scope, however, in two important respects. First, Congress required EPA to consider environmental effects in addition to health effects. Second, Congress required the Agency to consider the cumulative effects of Hg from all sources, including EGUs. In considering the cumulative effects of Hg, the Agency was not required to apportion the cause of any adverse effects among the various sources of Hg. Both the Utility and Mercury Studies considered the control technologies available to control Hg emissions, but only the Mercury Study called for the evaluation of the costs of such controls. Section 112(n)(1)(B).

EPA believes that Congress directed the Agency to conduct the Utility Study so that the Agency would understand the hazards to public health posed by HAP emissions from EGUs alone, and consider whether any hazards that were identified would be addressed through imposition of the requirements of the CAA applicable to EGUs at that time. Congress provided EPA an additional year to examine the impacts of EGU emissions of Hg on health and the environment in combination with other sources of Hg emissions.

The NAS Study required by section 112(n)(1)(C), which was due at the same time as the Utility Study, was to focus on Hg only and the adverse human health effects associated with Hg. The statute directed the determination of the threshold level of Hg below which adverse effects to human health are not expected to occur. The statute further directed the determination of the threshold for Hg concentrations in the tissue of fish which may be consumed, including by sensitive populations, without adverse effects to public health. Here, unlike the Utility Study and the Mercury Study, the statute specifically requires an evaluation of the adverse human health effects of Hg on sensitive populations.

The remaining critical element of section 112(n)(1) is the direction to EPA to determine whether it is appropriate and necessary to regulate EGUs under section 112, considering the results of the Utility Study. Although the Utility Study is a condition precedent to making the appropriate and necessary determination, nothing in section 112(n)(1)(A) precludes the Agency from considering other information in making that determination.

Taken together, we believe these provisions provide a framework for the Agency's determination of whether to regulate HAP emissions from EGUs under section 112. Through these provisions, Congress sought a prompt review and evaluation of the hazards to public health and the environment associated with Utility HAP emissions. This prompt consideration of health and environmental impacts is consistent with the strict deadlines Congress imposed in section 112 on all other source categories.

See infra.

Section 112(n)(1)(B) is direct evidence that Congress was concerned with environmental effects and cumulative impacts of HAP emissions from EGUs and other sources, particularly with regard to the bio-accumulative HAP Hg. Section 112(n)(1)(C) provides further evidence that Congress was concerned with limiting HAP emissions from EGUs to a level that protects sensitive populations. We believe the scope of the Utility Study was limited to HAP emissions from EGUs and hazards to public health, not because Congress was unconcerned with adverse environmental effects or the cumulative impact of HAP emissions, but because the Utility Study, as required, was a significant undertaking in itself and Congress wanted the Agency to complete the study within 3 years. Thus, section 112(n)(1) reveals, among other things, Congress' concern for the health and environmental effects of HAP emissions from EGUs, both alone and in conjunction with other sources, the impact of Hg emissions from EGUs, and the availability of controls to address HAP emissions from EGUs.

Finally, significantly, nowhere in section 112(n)(1) does Congress require the consideration of costs in assessing health and environmental impacts. The only reference to costs is in section 112(n)(1)(B) and that reference required the Agency to consider the costs of emission reduction controls for Hg.

2. Interpretation of Key Terms

Section 112(n)(1)(A) itself provides no clear standard to govern EPA's analysis and determination of whether it is “appropriate and necessary” to regulate utilities under section 112. The statute simply requires EPA to regulate EGUs under section 112 if it determines that such regulation is appropriate and necessary, after considering the results of the Utility Study. As noted above, courts have interpreted the terms appropriate and necessary as conveying considerable discretion to the Agency in determining what is appropriate and necessary in a given context.

As explained more fully below, in this context, we interpret the statute to require the Agency to find it

appropriate

to regulate EGUs under CAA section 112 if the Agency determines that the emissions of one or more HAP emitted from EGUs pose an identified or potential hazard to public health or the environment at the time the finding is made. If the Agency finds that it is

appropriate

to regulate, it must find it

necessary

to regulate EGUs under section 112 if the identified or potential hazards to public health or the environment will not be adequately addressed by the imposition of the requirements of the CAA. Moreover, it

may be

necessary

to regulate utilities under section 112 for a number of other reasons, including, for example, that section 112 standards will assure permanent reductions in EGU HAP emissions, which cannot be assured based on other requirements of the CAA.

The following subsections describe in detail our interpretation of the key statutory terms. We also explain below how the interpretations set forth in this notice are wholly consistent with the December 2000 Finding. Further, to the extent our interpretation differs from that set forth in the 2005 Action, we explain the basis for that difference and why the interpretation, as set forth in this preamble, is reasonable.

See National Cable & Telecommunications Ass'n, et al.

Brand X Internet Services, et al.,

545 U.S. 967, 981 (2005) (Discussing the deference provided to an Agency when changing interpretations the Court stated “change is not invalidating, since the whole point of

Chevron

deference is to leave the discretion provided by ambiguities of a statute with the implementing agency.”) (Internal citations and quotations omitted);

see

also

Department of Treasury

FLRA,

494 U.S. 922, 933 (1990) (Finding that EPA's judgment should only be overturned if it is deemed unreasonable, not merely because other, reasonable alternatives exist).

a. “Appropriate” To Regulate EGUs

We interpret section 112(n)(1)(A) to require the Agency to find regulation of EGUs under section 112 appropriate if we determine that HAP emissions from EGUs pose a hazard to public health or the environment at the time the finding is made. The hazard to public health or the environment may be the result of HAP emissions from EGUs alone or the result of HAP emissions from EGUs in conjunction with HAP emissions from other sources. In addition, EPA must find that it is appropriate to regulate EGUs if it determines that any single HAP emitted by utilities poses a hazard to public health or the environment. We further interpret the term “appropriate” to not allow for the consideration of costs in assessing whether HAP emissions from EGUs pose a hazard to public health or the environment. Finally, we may conclude that it is appropriate, in part, to regulate EGUs if we determine that there are controls available to address HAP emissions from EGUs.

i. Basis for Interpretation

As stated above, the appropriate finding may be based on hazards to public health or the environment. Although we believe that Congress' primary concern, as expressed in section 112(n)(1)(A) and 112(n)(1)(C), related to hazards to public health, the inclusion of environmental effects in section 112(n)(1)(B) indicates Congress' interest in protecting the environment from HAP emissions from EGUs as well.

Moreover, the term “appropriate” is extremely broad and nothing in the statute suggests that the Agency should ignore adverse environmental effects in determining whether to regulate EGUs under section 112. Further, had Congress intended to prohibit EPA from considering adverse environmental effects in the “appropriate” finding, it would have stated so expressly. Absent clear direction to the contrary, and considering the purpose of the CAA (

see e.g.,

CAA section 101, 112(c)(9)(B)(ii)), it is reasonable to consider environmental effects in evaluating the hazards posed by HAP emitted from EGUs when assessing whether regulation of EGUs under section 112 is appropriate. Accordingly, we interpret the statute to authorize the Agency to base the appropriate finding on either hazards to public health or the environment.

We also maintain that the Agency should base its “appropriate” evaluation on the hazards to public health or the environment that exist at the time the determination is made, not after considering the imposition of the other requirements of the CAA. The Agency evaluates whether imposition of the requirements of the CAA will adequately address any identified hazards only in the context of the necessary finding. Thus, in assessing whether regulation of EGUs is appropriate under section 112, we evaluate the current hazards posed by such units, as opposed to projecting what such hazards may look like after imposition of the requirements of the CAA.

We further interpret the CAA as allowing the Agency to base the appropriate finding on hazards to public health or the environment that result from HAP emissions from EGUs alone or hazards to public health and the environment that result from HAP emissions from EGUs in conjunction with HAP emissions from other sources. Section 112(n)(1) does not focus exclusively on EGU-only HAP emissions.

As explained above, section 112(n)(1)(B) and (C) require either expressly or implicitly the consideration of Hg emissions from all sources, not just EGUs. Section 112(n)(1)(B) is of note because that provision does not require the Agency to determine the hazard posed by Hg from EGUs alone. Rather, Congress required EPA to evaluate the health and environmental effects of Hg emissions from “electric utility steam generating units, municipal waste combustion units, and other sources, including area sources.” Section 112(n)(1)(C) is also relevant because it requires a human health-based assessment of the hazards posed by Hg without regard to the origin of the Hg. Congress could have directed an evaluation of the human health risk attributable to EGUs alone, but it did not. Congress also did not require such an assessment be conducted in the NAS Study.

In addition, Congress directed the Agency in section 112(n)(1)(A) to regulate EGUs under section 112 if the results of the Utility Study caused the Agency to conclude that regulation was appropriate and necessary. Section 112(n)(1)(A) is not written in a manner to preclude consideration of other information when determining whether it is appropriate and necessary to regulate EGUs under section 112, and that includes consideration of all hazards, both health and environmental, posed by HAP emitted by EGUs.

See United States

United Technologies Corp.,

985 F.2d 1148, 1158 (2d Cir. 1993) (“based upon” does not mean “solely”).

Finally, focusing on HAP emissions from EGUs alone when making the appropriate finding ignores the manner in which public health and the environment are affected by air pollution. An individual that suffers adverse health effects as the result of the combined HAP emissions from EGUs and other sources is harmed, irrespective of whether HAP emissions from EGUs alone would cause that harm. For this reason, we believe we may consider the hazards to public health and the environment posed by HAP emissions from EGUs alone or in conjunction with HAP emissions from other sources.

Furthermore, the appropriate finding may be based on a finding that any single HAP emitted from EGUs poses a hazard to public health or the environment. Nothing in section 112(n)(1)(A) suggests that EPA must determine that every HAP emitted by EGUs poses a hazard to public health or the environment before EPA can find it appropriate to regulate EGUs under section 112. Interpreting the statute in this manner would preclude the Agency from addressing under section 112 identified or potential hazards to public health or the environment associated with HAP emissions from EGUs unless

we found a hazard existed with respect to each and every HAP emitted.

Indeed, Congress' focus in section 112(n)(1)(B) and (C) on Hg indicates Congress' awareness that Hg was a problem and supports the position that EPA could find it appropriate to regulate EGUs based on the adverse health and environmental effects of a single HAP. Furthermore, the statute does not directly or expressly authorize the Agency to regulate only those HAP for which a hazard finding has been made. In fact, the statute requires the Agency to regulate EGUs under section 112 if the Agency finds regulation under section 112 is appropriate and necessary, and regulation under section 112 for major sources requires MACT standards for

all HAP

emitted from the source category.

See, e.g.,

National Lime Ass'n

EPA,

233 F.3d 625, 633 (DC Cir. 2000). For these reasons, we conclude we must find it appropriate to regulate EGUs under section 112 if we determine that the emissions of any single HAP from such units pose a hazard to public health or the environment.

We also maintain that the better reading of the term “appropriate” is that it does not allow for the consideration of costs in assessing whether hazards to public health or the environment are reasonably anticipated to occur based on EGU emissions. Had Congress intended to require the Agency to consider costs in assessing hazards to public health or the environment associated with EGU HAP emissions, it would have so stated.

This interpretation is consistent with the overall structure of the CAA. Congress did not authorize the consideration of costs in listing any source categories for regulation under section 112. In addition, Congress did not permit the consideration of costs in evaluating whether a source category could be delisted pursuant to the provisions of section 112(c)(9).

Under section 112(n)(1)(A), EPA is evaluating whether to regulate HAP emissions from EGUs at all. It is reasonable to conclude that costs may not be considered in determining whether to regulate EGUs under section 112 when hazards to public health and the environment are at issue.

Finally, consistent with sections 112(n)(1)(A) and 112(n)(1)(B), we conclude that we may base the appropriate finding on the availability of controls to address HAP emissions from EGUs.

ii. The December 2000 Finding

The Agency's interpretation of the term “appropriate,” as set forth above, is wholly consistent with the Agency's appropriate finding in December 2000. As noted above, in 2000, we concluded that it was appropriate to regulate EGUs under section 112 because Hg in the environment posed a hazard to public health and the environment. The Agency also concluded it was appropriate because of uncertainties associated with the hazards posed by other HAP emitted from EGUs. 65 FR 79827. Finally, the EPA concluded that it was appropriate because of the availability of controls to reduce HAP emissions from EGUs. In making the finding as it related to Hg, the Agency considered the hazards posed by Hg in the environment and the contribution of EGUs to that hazard. In addition, EPA did not consider costs when making the appropriate determination. Further, the appropriate finding evaluated the hazards at the time, as opposed to the hazards remaining after imposition of the requirements of the CAA. EPA evaluated whether the other requirements of the CAA would adequately address the hazards in the necessary prong only.

As explained below, EPA reasonably concluded in December 2000 that it was appropriate and necessary to regulate EGUs under section 112 based on the record before the Agency at that time.

iii. The 2005 Action

As noted above, in 2005, EPA revised its December 2000 Finding and stated that the appropriate finding: (1) Could not be based on adverse environmental effects; (2) must be made considering only HAP emissions from EGUs; (3) must be made after consideration of the imposition of the requirements of the CAA; and (4) must consider other factors (

e.g.,

costs) even if we determine that HAP emissions from EGUs pose a hazard to public health. This proposal differs from the 2005 Action, and we address each of these differences below.

First, we change the position taken in 2005 that the appropriate finding could not be based on environmental effects alone. In 2005, we did not properly consider all of the provisions of section 112(n)(1). The Agency should not interpret the CAA to limit the Agency's discretion to protect the environment absent clear direction to that effect. In essence, the Agency's interpretation in 2005 would have required the Agency to ignore a catastrophic environmental harm (

e.g.,

the extinction of a species) if the Agency could not also identify a hazard to public health. EPA took this position regarding environmental effects in 2005 even though in that same rule it correctly interpreted section 112(n)(1)(A) to allow the Agency to consider information beyond the Utility Study in making the appropriate and necessary determination. 70 FR 15,997-99. The 2005 interpretation that EPA cannot consider environmental effects in evaluating whether it is appropriate to regulate EGUs under section 112 was neither reasonable nor consistent with the goals of the CAA, and, therefore, we are rejecting that interpretation and returning to the approach taken in 2000 that allowed consideration of environmental effects.

Second, for all of the reasons stated above, we are revisiting the 2005 interpretation that required the Agency to consider HAP emissions from EGUs without considering the cumulative impacts of all sources of HAP emissions. Nothing in section 112(n)(1)(A) prohibits consideration of HAP emissions from EGUs in conjunction with HAP emissions from other sources of HAP. We believe it is more reasonable to interpret the statute to authorize the Agency to consider the cumulative effects of HAP that are emitted from EGUs and other sources. This interpretation allows the Agency to evaluate more fully whether HAP emissions from EGUs pose a hazard to public health or the environment consistent with the manner in which the public and the environment are exposed to HAP emissions.

Third, we are revising the 2005 interpretation that required the Agency to evaluate the hazards to public health after imposition of the requirements of the CAA. We conclude today that in 2005 the Agency improperly conflated the appropriate finding and the necessary finding by requiring consideration of the ameliorative effects of other CAA requirements in both prongs of the appropriate and necessary finding. We believe the Agency must find it appropriate to regulate EGUs under section 112 if we determine that HAP emitted by EGUs pose a hazard to public health or the environment at the time the finding is made. The issue of how and whether those hazards are reduced after imposition of the requirements of the CAA is an issue for the necessary prong of the finding.

Finally, we are rejecting the 2005 interpretation that authorizes the Agency to consider other factors (

e.g.,

cost), even if the Agency determines that HAP emitted by EGUs pose a hazard to public health (or the environment). We reject the consideration of costs for all the reasons set forth above. Furthermore, the better reading of section 112(n)(1)(A) is that the Agency should find it appropriate to regulate EGUs under section 112 if a hazard to public health or the environment is identified. We think it

unreasonable to decline to make the appropriate finding based on any factor, cost or otherwise, if we determine that EGUs pose a hazard to public health or the environment.

b. “Necessary” To Regulate EGUs

Once the Agency has determined that it is appropriate to regulate EGUs under section 112, the Agency must then determine whether it is necessary to regulate EGUs under section 112. As stated above, we have considerable discretion to determine whether regulation of EGUs under section 112 is necessary. The DC Circuit Court has stated that “there are many situations in which the use of the word `necessary,' in context, means something that is done, regardless of whether it is indispensible, to achieve a particular end.”

Cellular Telecommunication,

330 F.3d at 510.

If the Agency concludes that it is appropriate to regulate EGUs, we believe it is necessary to regulate HAP emissions from EGUs if we determine that the imposition of the requirements of the CAA will not sufficiently address the identified hazards to public health or the environment posed by HAP that are emitted from EGUs. We maintain that we must find it necessary based on such a finding even if regulation under section 112 will not fully resolve the identified hazard to public health or the environment.

We may also determine it is necessary to regulate under section 112 if we are uncertain whether the imposition of the other requirements of the CAA will sufficiently address the identified hazards. We may find it necessary to regulate EGUs under section 112 even if we were to conclude, based on reasonable estimations of emissions reductions, that the imposition of the other requirements of the CAA would, or might, significantly reduce the identified hazard, because the only way to guarantee that such reductions will occur at all EGUs and be maintained is through a section 112(d) standard that directly regulates HAP emissions from utilities. Finally, we may also find it necessary to regulate EGUs under section 112 to further the policy goal of supporting international efforts to reduce HAP emissions, including Hg.

i. Necessary After Imposition of the Requirements of the CAA

In the Utility Study, Congress directed the Agency to evaluate the hazards to public health posed by HAP emissions from EGUs remaining after imposition of the requirements of the CAA, and it gave EPA 3 years to complete that Study. We interpret the necessary requirement first in the context of the phrase “after imposition of the requirements of [the CAA].” Section 112(n)(1)(A).

Congress did not define the phrase “after imposition of the requirements of the Act.” The plain meaning of the term “requirement” is something that is necessary, or obligatory.

See, e.g.,

Random House Webster's Unabridged Dictionary, Deluxe Edition, 2001. Given that Congress intended the Utility Study to be completed by 1993, it is reasonable to interpret the phrase “after imposition of the requirements of the Act”, as requiring the Agency to consider only those requirements that Congress directly imposed on EGUs through the CAA as amended in 1990 and for which EPA could reasonably predict HAP emission reductions at the time of the Utility Study. The most substantial requirement in this regard was the newly enacted ARP.

The purpose of the ARP was to reduce the adverse effects of acid deposition (more commonly known as “acid rain”), by limiting the allowable emissions of SO

and NO

primarily from EGUs. In enacting the Acid Rain provisions of the Act, Congress explained that the problem of acid deposition was one of “national and international significance,” that technologies to reduce the precursors to acid deposition were “economically feasible,” and that “control measures to reduce precursor emissions from steam-electric generating units should be initiated without delay.” CAA section 401(a). The ARP also includes a series of very specific emission reduction requirements. For example, the goals of the program include a reduction of annual SO

emissions by 10 million tons below 1980 levels and a reduction of NO

emissions by two million tons from 1980 levels.

Moreover, the ARP achieved the required reductions by allocating allowances to emit SO

at reduced levels to each affected EGU. Sources were prohibited from emitting more SO

than the number of allowances held. To comply with these requirements, source owners or operators could elect to install controls, such as scrubbers, switch to lower sulfur fuels at their facilities, or purchase allowances from other EGUs that had reduced their emissions beyond what they were required by the ARP to achieve. It was known at the time of enactment of the 1990 Amendments that the controls used to reduce emissions of SO

, primarily scrubbers, had the co-benefit of controlling HAP emissions, including Hg emissions. The ARP also included requirements for limiting NO

emissions from EGUs. Considering the Acid Rain requirements under section 112(n)(1) is reasonable because the Act contained very specific emission reduction requirements for EGUs, and a tight compliance time-frame. In fact, all of the regulations implementing the SO

allowance trading portion of the ARP were completed by the mid-1990's.

The other significant requirement that Congress imposed in the 1990 Amendments was to revise the NSPS for NO

emissions from EGUs by 1994. CAA 407(c). However, unlike the SO

allowance requirements of the ARP, Congress did not specify the amount of required reductions, but instead directed EPA to consider the improvements in methods for reducing NO

when establishing standards for new sources. Thus, in the 1990 Amendments, Congress sought NO

reductions from EGUs both through the ARP and a revision of the NSPS applicable to new sources. The Agency issued these NSPS in 1997.

There are other requirements of Title I of the Act that could affect EGUs, and they include the National Ambient Air Quality Standards (NAAQS). Congress did not impose these provisions directly on EGUs, however. Instead, EPA is responsible for developing the NAAQS, and states are primarily responsible for assuring attainment and maintenance of the NAAQS. For example, EPA stated in the Utility Study that implementation of the 1997 NAAQS for ozone and PM may lead to reductions in Hg emissions, but those potential reductions could not be sufficiently quantified because states have the ultimate responsibility for implementing the NAAQS. See Utility Study, pages ES-25, 1-3, 2-32, 3-14, and 6-15. States use a broad combination of measures (mobile and stationary) to obtain the reductions needed to meet the NAAQS. These decisions are unique to each state, as each state must identify and assess the sources contributing to nonattainment and determine how best to meet the NAAQS. EPA cannot predict with any certainty precisely how states will ensure that the reductions needed to meet the NAAQS will be realized. Moreover, there are additional uncertainties even were a state to impose requirements on EGUs through a State Implementation Plan (SIP), because each EGU may choose to meet the required reductions in a different manner, which could result in more or less HAP emission reductions. Accordingly, we do not believe it would have been appropriate to include such potential emissions reductions in determining whether it is necessary to

regulate HAP emissions from EGUs under section 112.

Further, it is reasonable to interpret the phrase “after imposition of the requirements of the Act”, as only requiring consideration of those requirements that Congress directly imposed on EGUs through the CAA as amended in 1990 and for which EPA could reasonably predict emission reductions at the time of the Utility Study. To interpret the phrase otherwise would require the Agency to look ahead two to three decades to forecast what possible requirements might be developed and applied to EGUs under some requirement of the CAA at some point in the future.

Indeed, such an interpretation would be inconsistent with the structure and purpose of section 112. As noted above, Congress gave EPA until 1993 to issue the Utility Study and expected the appropriate and necessary finding would follow shortly thereafter. Congress also required EPA to address HAP emissions rapidly from all source categories. See CAA 112(e), supra. It is reasonable to presume that Congress intended EPA to evaluate the need for EGU HAP controls in light of the requirements imposed upon the industry via the new 1990 requirements. Obviously the central requirement that was new and applied to EGUs was the ARP which would be implemented rapidly following passage of the 1990 amendments to the Act.

Although the above represents a reasonable interpretation of what Congress contemplated the Utility Study would examine with regard to “imposition of the requirements of the Act,” we recognize that we have discretion to look beyond the Utility Study in determining whether it is necessary to regulate EGUs under section 112. Given that several years have passed since the December 2000 Finding, we conducted additional analysis. Although not required, we conducted this analysis to demonstrate that even considering a broad array of diverse requirements, it remains appropriate and necessary to regulate EGUs under section 112.

Specifically, we examined a host of requirements, which in our view, far surpass anything Congress could have contemplated in 1990 we would consider as part of our “necessary” determination. For example, our analysis includes certain state rules regulating criteria pollutants, Federal consent decrees, and settlement agreements for criteria pollutants resolving state-initiated and citizen-initiated enforcement actions.

We did not include in our analysis any state-only HAP requirements or voluntary actions to reduce HAP emissions, as those are not requirements of the CAA, and are not required by Federal law to remain applicable.

In our analysis, we included state requirements and citizen and state settlements associated with criteria pollutants because those requirements may have a basis under the CAA. We did not, however, conduct an analysis to determine whether that was the case in each instance. As such, we believe there may be instances where we should not have considered certain state rules or state and citizen suit settlements in our analysis, because those requirements are based solely in state law and are not required by Federal law.

Although, as explained below, our technical analysis examined impacts projected out to 2016, this is a very conservative approach. Given that two decades have passed since the enactment of the 1990 CAA Amendments, we believe we can find it appropriate and necessary to regulate EGUs under section 112, if we determine EGU HAP emissions pose a hazard to public health and the environment today without considering future HAP emission reductions. Congress could not have contemplated in 1990 that EPA would have failed in 2011 to have regulated HAP emissions from EGUs where hazards to public health and the environment remain.

ii. Necessary Interpretation

If we determine that the imposition of the requirements of the CAA will not address the identified hazards, EPA must find it necessary to regulate EGUs under section 112. Section 112 is the authority Congress provided to address hazards to public health and the environment posed by HAP emissions and section 112(n)(1)(A) requires the Agency to regulate under section 112 if we find regulation is “appropriate and necessary.” If we conclude that HAP emissions from EGUs pose a hazard today, such that it is appropriate, and we further conclude based on our scientific and technical expertise that the identified hazards will not be resolved through imposition of the requirements of the CAA, we believe there is no justification in the statute to conclude that it is not necessary to regulate EGUs under section 112.

Furthermore, we believe it is necessary to regulate if we have identified a hazard to public health or the environment that will not be addressed by imposition of the requirements of the CAA even if regulation of EGUs under section 112 will not fully resolve the identified hazard. We conclude that this is particularly true for bio-accumulative HAP such as Hg because EPA can only address such emissions from domestic sources and mitigation of identified risks associated with such HAP is a reasonable goal.

See

section 112(c)(6). EPA cannot decline to find it “necessary” to regulate EGUs under section 112 when it has identified a hazard to public health or the environment, simply because that regulation will not wholly resolve the identified hazards. The statute does not require the Agency to conclude that identified hazards will be fully resolved before it may find regulation under section 112 necessary.

See Massachusetts

EPA,

549 U.S. 497, 525 (2007).

In addition, we may determine it is necessary to regulate under section 112 even if we are uncertain whether the imposition of the requirements of the CAA will address the identified hazards. Congress left it to EPA to determine whether regulation of EGUs under section 112 is necessary. We believe it is reasonable to err on the side of regulation of such highly toxic pollutants in the face of uncertainty. Further, if we are unsure whether the other requirements of the CAA will address an identified hazard, it is reasonable to exercise our discretion in a manner that assures adequate protection of public health and the environment. Moreover, we must be particularly mindful of CAA regulations we include in our modeled estimates of future emissions if they are not final or are still subject to judicial review (

i.e.,

the Transport Rule

). If such rules are either not finalized or upheld by the Courts, the level of risk would potentially increase.

Federal Implementation Plans To Reduce Interstate Transport of Fine Particulate Matter and Ozone. Proposed Rule. August 2, 2010. 75 FR 45,210.

We also may find it necessary to regulate EGUs under section 112 even if we conclude, based on reasonable estimations of emissions reductions, that the imposition of the other requirements of the CAA will significantly reduce the identified hazard. We maintain this is reasonable because the only way to guarantee that the necessary reductions in HAP emissions will occur at all EGUs and be maintained is through a section 112(d) standard that directly regulates HAP emissions from EGUs. This is true because sources could discontinue use of controls for criteria pollutants that achieve HAP reductions as a co-benefit if new control technologies or practices are identified that reduce the relevant criteria pollutants but do not also reduce HAP. For example, scrubbers are often used to reduce SO

emissions and those scrubbers also reduce emissions of several HAP. However, if an EGU with a scrubber started complying with its SO

standard by switching to low sulfur coal or purchasing allowances, the HAP

emission reduction co-benefits associated with the scrubber would no longer be realized. In addition, at the time Congress passed the 1990 CAA amendments, there were many older EGUs that had few or no controls in place. Over 20 years later, there remain a significant number of older EGUs that are only minimally controlled. The Agency may find it necessary to regulate EGUs under section 112 to ensure that these minimally controlled EGUs and those units that switch to other criteria pollutant compliance options, thereby no longer achieving the same HAP reductions, are subject to HAP regulation, such that the estimated reductions in the identified hazards are realized.

iii. December 2000 Finding

Our interpretation of the necessary finding is reasonable and consistent with the December 2000 Finding. In that finding, EPA determined that the imposition of the requirements of the CAA would not address the serious public health and environmental hazards resulting from EGU HAP emissions. We also stated that section 112 is the authority to address hazards from HAP emissions. Because we determined that the imposition of the requirements of the CAA would not address the identified hazards, we correctly concluded it was necessary to regulate under section 112. Although the Agency did not expressly interpret the term necessary in the December 2000 Finding, under the interpretation set forth above, the Agency must find it necessary if we conclude that the imposition of the other requirements of the CAA will not address the identified hazards. Because EPA reached that conclusion, the Agency correctly determined that it was necessary to regulate EGU HAP emissions and did not need to base the 2000 necessary finding on any of the other bases set forth above.

iv. The 2005 Action

We stated in 2005 that “it is necessary to regulate EGUs under section 112 only if there are no other authorities under the CAA that, if implemented, would effectively address the remaining HAP emissions from EGUs.” 70 FR 16,001.

In essence, we stated in 2005 that section 112(n)(1)(A) requires the Agency to scour the CAA to determine whether there is a direct or indirect manner in which EPA could regulate HAP emissions from EGUs, notwithstanding the fact that Congress expressly provided section 112 for the purpose of regulating HAP emissions from stationary sources. This interpretation is not reasonable.

In the rule reconsidering the 2005 Action, we further clarified that in evaluating the effectiveness of other CAA authorities we considered whether those other authorities could be implemented in a cost-effective and administratively effective manner. 71 FR 33,391. We need not address this in detail because we conclude that the threshold conclusion that the Agency must look for alternative CAA authorities that could be used to regulate HAP emissions from EGUs before finding it necessary is invalid.

Congress enacted section 112 for the express purpose of regulating HAP emissions. It is not reasonable to interpret section 112(n)(1)(A) to require the Agency to find another provision of the CAA to address identified hazards to public health or the environment. This is particularly the case where the Agency would not have certainty that such alternative legal theory would withstand judicial scrutiny because section 112 is the authority expressly provided to regulate HAP emissions and no other provision provides express authority to regulate HAP emissions from existing stationary sources.

Although anyone can challenge the substance of a section 112 standard, no one can challenge that regulation of HAP emissions under section 112 is proper for validly listed source categories.

In theory, an NSPS is legally permissible for new stationary sources of HAP.

Furthermore, section 112(n)(1)(A) states explicitly that the Agency shall regulate EGUs “under this section” if the Agency determines it is “appropriate and necessary after considering the results of the (Utility Study).” We reiterate that the only precondition to regulating EGUs is consideration of the results of the Utility Study. We believe it is unreasonable to argue that Congress directed the Agency as part of the Utility Study to scour the CAA for alternative legal authorities for regulating HAP emissions, either directly or indirectly. Indeed, the Agency did not interpret the requirement in section 112(n)(1)(A) to conduct the study in that manner, as evidenced by the Utility Study itself. Absent that interpretation, we think it is unreasonable to conclude that the Agency must undertake such an effort to make the necessary finding because Congress authorized the Agency to base the “appropriate and necessary” finding on the Utility Study alone.

For all the reasons above, we believe it is appropriate to regulate EGUs under section 112 if the Agency determines that HAP emissions from such units pose a hazard to public health or the environment at the time of the finding, and it is necessary to regulate EGUs under section 112 if the imposition of the other requirements of the CAA will not adequately address the identified hazards to public health or the environment, or there are other compelling reasons making it necessary to regulate HAP emissions from EGUs under section 112.

c. Hazards to Public Health or the Environment

Section 112(n)(1)(A) neither defines the phrase “hazards to public health,” nor sets forth parameters for EPA to use in determining whether HAP emissions from EGUs pose a hazard to public health. The phrase is also not defined elsewhere in the CAA. EPA, therefore, has broad discretion, using its technical and scientific expertise, to determine whether HAP emissions from EGUs pose a hazard to public health.

In evaluating hazards to the environment, however, Congress did provide some direction. Specifically, it defined the term “adverse environmental effects” in section 112(a)(7), and as explained further below, we evaluate hazards to the environment consistent with that definition.

Because Congress did not define “hazard to public health” the Agency must use its scientific and technical expertise to determine what constitutes a hazard to public health in the context of EGU HAP emissions. The Agency considers various factors in evaluating hazards to public health, including, but not limited to, the nature and severity of the health effects associated with exposure to HAP emissions; the degree of confidence in our knowledge of those health effects; the size and characteristics of the populations affected by exposures to HAP emissions; the magnitude and breadth of the exposures and risks posed by HAP emissions from a particular source category, including how those exposures contribute to risk in populations with additional exposures to HAP from other sources; and the proportion of the population exposed above benchmark levels of concern (

e.g.,

cancer risks greater than 1 in a million or non-cancer effects with a hazard quotient (HQ) greater than 1). See Section III(D) below for a discussion of the Agency's technical conclusions as to whether a hazard to public health or the environment exists based on the facts at issue here.

Although Congress provided no definition of hazard to public health, section 112(c)(9)(B) is instructive. In that section, Congress set forth a test for removing source categories from the section 112(c) source category list. That

test is relevant because it reflects Congress' view as to the level of health effects associated with HAP emissions that Congress thought warranted continued regulation under section 112. The Agency finds section 112(c)(9)(B)(i) particularly instructive because it provides a numerical threshold for HAP that may cause cancer. Specifically, that provision provides that EPA may delete a source category from the section 112(c) list if no source in the category emits such HAP in quantities which may cause a lifetime risk of cancer

greater than one in one million

to the individual in the population who is most exposed to such HAP emissions. Thus, the Agency reads section 112(c)(9)(B)(i) to reflect Congress' view of the acceptable hazard to public health for HAP that may cause cancer.

Congress defined the phrase “adverse environmental effect” in section 112(a)(7) to mean “any significant and widespread adverse effect, which may reasonably be anticipated, to wildlife, aquatic life, or other natural resources, including adverse impacts on populations of endangered or threatened species or significant degradation of environmental quality over broad areas.”

Section 112(n)(1)(B) required EPA to examine the environmental effects of Hg emissions. Because Congress defined the term “adverse environmental effect” in section 112(a)(7), we believe that such definition should guide our assessment of whether hazards to the environment posed by Utility HAP emissions exist. As with hazards to public health, however, the Agency must use its discretion to determine whether the adverse environmental effects identified warrant a finding that it is appropriate to regulate HAP emissions from EGUs based on those effects. In evaluating the environmental effects, we have stated that we may consider various aspects of pollutant exposure, including: “[t]oxicity effects from acute and chronic exposures” expected from the source category (as measured or modeled); “persistence in the environment;” “local and long-range transport;” and “tendency for bio-magnification with toxic effects manifest at higher trophic levels.” 67 FR 44,718 (July 3, 2002).

In interpreting the term itself, we believe the broad language in section 112(a)(7) referring to “any” enumerated effect “which may be reasonably anticipated” evinces Congressional intent to not restrict the scope of that term to only certain specific impacts. 62 FR 36440 (July 7, 1997); 63 FR 14094 (March 24, 1998). Further, the section 112(a)(7) reference to “any” enumerated effect in the singular clearly contemplates impacts of limited geographic scope, suggesting that the “widespread” criterion does not present a particularly difficult threshold to cross.

Id.

This is further supported by the fact that section 112(a)(7) provides as an example of adverse environmental effects, adverse impacts on populations of endangered or threatened species, which as reflective of their imperiled status are especially likely to exist in limited geographic areas. EPA believes that the “widespread” criterion would not exclude impacts that might occur in only one region of the country.

Id.

d. Regulating EGUs “Under This Section”

The statute directs the Agency to regulate EGUs under section 112 if the Agency finds such regulation is appropriate and necessary. Once the appropriate and necessary finding is made, EGUs are subject to section 112 in the same manner as other sources of HAP emissions. Section 112(n)(1)(A) provision provides, in part, that:

[t]he Administrator shall perform a study of the hazards to public health reasonably anticipated to occur as a result of emissions by electric utility steam generating units of pollutants listed

under subsection (b) of this section

after imposition of the requirements of this chapter * * * The Administrator shall regulate electric utility steam generating units

under this section,

if the Administrator finds such regulation is appropriate and necessary after considering the results of the study required

by this subparagraph.

Emphasis added.

In the first sentence, Congress described the study and directed the Agency to evaluate the hazards to public health posed by HAP emissions listed

under subsection

(b) (

i.e.,

section 112(b)). The last sentence requires the Agency to regulate under this section (

i.e.,

section 112) if the Agency finds such regulation is appropriate and necessary after considering the results of the study required by

this subparagraph

(

i.e.,

section 112(n)(1)(A)). The use of the terms section, subsection, and subparagraph demonstrates that Congress was consciously distinguishing the various provisions of section 112 in directing the conduct of the study and the manner in which the Agency must regulate EGUs if the Agency finds it appropriate and necessary to do so. Congress directed the Agency to regulate utilities “under this section,” and accordingly EGUs should be regulated in the same manner as other categories for which the statute requires regulation.

Furthermore, the DC Circuit Court has already held that section 112(n)(1) “governs how the Administrator decides whether to list EGUs” and that once listed, EGUs are subject to the requirements of section 112.

New Jersey,

517 F.3d at 583. Indeed, the DC Circuit Court expressly noted that “where Congress wished to exempt EGUs from specific requirements of section 112, it said so explicitly,” noting that “section 112(c)(6) expressly exempts EGUs from the strict deadlines imposed on other sources of certain pollutants.”

Id.

Congress did not exempt EGUs from the other requirements of section 112, and once listed, EPA is required to establish emission standards for EGUs consistent with the requirements set forth in section 112(d), as described above.

EPA requests comment on section III.A.

B. The December 2000 Appropriate and Necessary Finding was Reasonable

EPA reasonably determined in December 2000 that it was appropriate and necessary to regulate HAP emissions from EGUs under CAA section 112. In making that finding, EPA considered all of the information that Congress had identified as most salient, including the Utility Study, the Mercury Study, and the information in the NAS Study.

EPA even conducted an ICR soliciting emissions information on Hg, which was the HAP of most concern to Congress, as evidenced by section 112(n)(1). EPA collaborated further with a number of other entities and Federal Agencies, including the U.S. Department of Energy (DOE). EPA carefully evaluated all of this information, much of which had been the subject of extensive peer review, and reasonably determined, on the record before the Agency at the time, that it was appropriate and necessary to regulate EGUs under section 112.

As explained above, we discuss the NAS Study here because it addressed the same issues as the NIEHS study, and it is the more recent study.

1. EPA Appropriately Based the Finding on the Information Required by Section 112(n)(1) and Reasonably Made the Finding Once It Had Completed the Required Studies

In making the appropriate and necessary finding in 2000, EPA considered all of the relevant information in the three Studies required by section 112(n)(1) and the NAS Study. 65 FR 79826-27. The Utility, Mercury, and NAS Studies together consisted of thousands of pages of information and technical analyses. All of these studies were peer reviewed prior to issuance. In fact, the Mercury Study was reviewed by over 65

independent scientists.

The NAS Study contains a thorough technical discussion summarizing the state of the science at the time regarding the human health effects of MeHg.

Mercury Study Report to Congress, Vol. I, Pg. 6, December 1997.

In addition to conducting the studies that Congress required, EPA collected relevant information on Hg emissions and available control technologies. Specifically, pursuant to a CAA section 114 ICR, EPA collected data on the Hg content in coal from all coal-fired EGUs for calendar year 1999. Through the 1999 ICR, EPA also obtained stack test data for certain coal-fired EGUs to verify Hg emissions estimates for the EGU source category. 65 FR 79826. EPA further solicited data from the public through a February 29, 2000, notice (65 FR 10,783), and provided the public an opportunity to provide its views on what the regulatory finding should be at a public meeting. 65 FR 79826 (citing 65 FR 18992). Finally, EPA undertook an evaluation of the Hg control performance of various emission control technologies that were either currently in use on EGUs or that could be applied to such units for Hg control. EPA conducted this evaluation with other parties, including the DOE. 65 FR 79826. EPA also evaluated other emission control approaches that would reduce EGU HAP emissions.

Id.

at 79827-29.

Although Congress did not provide a deadline by which EPA must issue the appropriate and necessary finding, the deadlines Congress provided for completion of the required studies signal that Congress wanted EPA to make the appropriate and necessary finding shortly after completion of the studies. Congress required that the Utility Study and NIEHS Study be submitted by November 15, 1993, and the Mercury Study by November 15, 1994. We reasonably conclude based on the timing of the studies that Congress wanted the Agency to evaluate the hazards to public health and the environment associated with HAP emissions from EGUs as quickly as possible and take steps to regulate such units under section 112 if hazards were identified.

Congress later provided a direct signal as to the timing of the appropriate and necessary finding in the committee report associated with EPA's fiscal year 1999 appropriations bill, which directed the Agency to fund the NAS Study. In that report, Congress indicated that it did not want the Agency to make the appropriate and necessary finding for Hg until the NAS study was completed.

See

H.R. Conf. Rep. No 105-769, at 281-282 (1998).

This direction is consistent with section 112(n)(1). As noted above, the Utility Study was the only condition precedent to making the appropriate and necessary finding. The NIEHS study called for by 112(n)(1)(C) was to have been completed at the same time as the Utility Study. As such, Congress had originally contemplated that both the Utility and NIEHS studies would be available at the time the Agency made the appropriate and necessary finding. The NAS study considered the same information required in the NIEHS study so the Congressional direction in the fiscal year 1999 appropriation is consistent with the original drafting of section 112(n)(1).

After considering all of the information that Congress considered most relevant, including the NAS Study that was issued in June 2000, EPA determined that it was appropriate and necessary to regulate EGUs under section 112 and listed such units for regulation on December 20, 2000. As explained below, the Agency acted reasonably in issuing the finding at that time because of the identified and potential hazards to public health and the environment associated with HAP emissions from utilities, which the Agency concluded would not be addressed through imposition of the requirements of the CAA. It would not have been reasonable to delay the finding to collect additional information given the considerable delay in completion of the required studies and the hazards to public health and the environment identified as of December 2000.

2. EPA Reasonably Concluded in December 2000 That It Was Appropriate To Regulate EGUs Under Section 112

The December 2000 Finding that it was appropriate to regulate EGUs under section 112 focused largely on hazards to public health and the environment associated with Hg emissions. EPA reasonably focused on this pollutant given that Hg is a persistent, bioaccumulative pollutant that causes serious neurotoxic effects. Indeed, Congress specifically identified this pollutant as one of concern and required two separate studies to be conducted regarding Hg emissions.

See

Section 112(n)(1)(B) and (C). The information before the Agency in 2000 concerning Hg was both well-documented and scientifically supported. Based on all of the information before it, the Agency concluded that Hg emissions from EGUs posed a hazard to public health. It was also reasonable for the Agency to find regulation of EGUs appropriate given the uncertainties regarding the extent of public health impacts posed by non-Hg HAP. Finally, it was reasonable to base the appropriate finding on the availability of controls for HAP emissions from EGUs.

a. The Agency Reasonably Concluded It Was Appropriate To Regulate EGUs Based on Hg Emissions

By 2000, the Agency had amassed “a truly vast amount of data” on Hg.

See

October 10, 1997, letter (page 2) submitting Science Advisory Board (SAB) peer review recommendations on draft Mercury Study.

Those data confirmed the hazards to public health and the environment associated with Hg. The data also helped EPA identify the populations of most concern with regard to MeHg exposure.

See

CAA 112(n)(1)(C). Finally, the data showed that EGUs were the largest unregulated source of Hg emissions in the U.S., and that EGUs were projected to increase their Hg emissions to approximately 60 tons in 2010.

http://yosemite.epa.gov/sab/SABPRODUCT.nsf/FF2962529C7B158A852571AE00648B72/$File/ehc9801.pdf

We discuss below the central pieces of data and information concerning Hg that formed the basis of our conclusion that Hg posed a threat to public health and the environment.

These conclusions were largely drawn from the Mercury Study, which, as noted above, was reviewed by over 65 peer reviewers. Upon reviewing the draft report, the SAB noted that the “major findings of the draft report are well supported by the scientific evidence.” In direct response to the SAB review, the Agency conducted additional, comprehensive analyses addressing SAB's recommendations. Thus, in 2000, the Agency had before it a comprehensive record concerning Hg emissions, including the best available science on Hg at the time.

The central conclusions underlying the 2000 finding are described in detail in the 2000 notice, at 65 FR 79829-30.

i. Key Facts: Impacts of Hg on Health and the Environment

EPA first concluded that Hg from EGUs was the HAP of greatest concern.

Id.

at 79827. The Agency explained that “mercury is highly toxic, persistent, and bioaccumulates in food chains;” that Hg deposited on land and water can then be metabolized by microorganisms into MeHg; that MeHg is “a highly toxic, more bioavailable, form that biomagnifies in the aquatic food chain (

e.g.,

fish);” and that nearly all of the Hg in fish is MeHg. 65 FR 79827. The Agency further noted that fish consumption is the primary route of exposure for humans and wildlife, and, by July 2000, 40 states and America Samoa had issued fish advisories for Hg,

with 13 of those states issuing advisories for all the water bodies in their state. 65 FR 79827. Finally, the Agency explained that neurotoxicity is the health effect of greatest concern with MeHg exposure, and that exposures to MeHg can have serious toxicological effects on wildlife as well as humans.

EPA recognized that increased Hg deposition would lead to increased levels of MeHg in fish and such “increased levels in fish [would] * * * lead to toxicity in fish-eating birds and mammals, including humans.” 65 FR 79830. EPA agreed with the NAS that “the long term goal needs to be the reduction in the concentrations of methylmercury in fish” and concluded that reducing Hg emissions from EGUs was “an important step toward achieving that goal.” 65 FR 79830.

The Agency then identified the most affected populations. Specifically, the Agency concluded that women of childbearing age are the population of greatest concern because the developing fetus is the most sensitive to the effects of MeHg. 65 FR 79827. EPA estimated that at that time, 7 percent of women of childbearing age (or about 4,000,000 women) in the continental U.S. were exposed to MeHg at levels that exceeded the RfD and that about 1 percent of women of childbearing age (or about 580,000 women) had MeHg exposures 3 to 4 times the RfD. 65 FR 79827.

The NAS Study affirmed EPA's assessment of the toxicity of MeHg and that the RfD EPA had developed for MeHg was valid. 65 FR 79827. The Agency acknowledged that there was uncertainty with risk at exposure above the RfD, but indicated that risk increased with increased exposure. 65 FR 79827. In addition to focusing on women of childbearing age and developing fetuses, EPA stated a particular concern for subsistence fish-eating populations due to their regular and frequent consumption of relatively large quantities of fish. 65 FR 79830.

As for environmental effects, the Agency observed adverse effects to avian species and wildlife in laboratory studies at levels corresponding to fish tissue MeHg concentrations that are exceeded by a significant percentage of fish sampled in lake surveys. 65 FR 79830. The Agency explained that wildlife consume fish from a more localized geographic area than humans, which can result in elevated levels of Hg in certain fish eating species. Those species include, for example, the kingfisher and some endangered species, such as the Florida panther. 65 FR 79830.

In summary, in the December 2000 Finding, EPA identified Hg in the environment as a hazard to public health and the environment, determined that a significant segment of the most sensitive members of the population were exposed to MeHg at levels exceeding the RfD, and confirmed that the RfD was valid.

ii. EGU Emissions of Hg

In the 2000 finding, the Agency estimated that about 60 percent of the total Hg deposited in the U.S. came from U.S. anthropogenic air emission sources. 65 FR 79827. The Agency stated that the remainder of the Hg deposited in the U.S. was from natural emission sources, reemissions of historic global anthropogenic Hg releases, and non-domestic anthropogenic sources of Hg. 65 FR 79827. EPA identified coal combustion and waste incineration as the source categories likely to bear the greatest responsibility for direct anthropogenic Hg deposition in the continental U.S. 65 FR 79827. EPA further explained that EGUs are the largest unregulated domestic source of Hg emissions, accounting for approximately 30 percent of the current anthropogenic air emissions from domestic sources. 65 FR 79827. These numbers, taken together, reveal that EGUs accounted for approximately 18 percent of the total Hg deposition in the U.S on an annual basis, considering all U.S. anthropogenic sources, natural emission sources, reemissions of historic global anthropogenic Hg releases, and non-domestic anthropogenic sources of Hg.

EPA estimated that U.S. anthropogenic air emissions of mercury accounted for 60 percent of total deposition in the U.S. and U.S. EGUs accounted for 30 percent of that deposited mercury. Thirty percent of the 60 percent contribution is equal to approximately 18 percent of the total deposition. See Utility Study, page 7-28.

In 2000, the Agency also found a plausible link between domestic anthropogenic Hg emissions and MeHg in fish. 65 FR 79829. The Agency explained that although that link could not be estimated quantitatively at the time, the facts before the Agency were sufficient for it to conclude that EGU Hg emissions posed a hazard to public health.

Id.

at 79830. Those facts included, for example, the link between coal consumption and Hg emissions, EGUs being the largest domestic source of Hg, and certain segments of the population being at risk for adverse health effects due to consumption of contaminated fish.

Id.

iii. EPA's Conclusions Regarding Hg

Based on the foregoing and all of the information set forth in the December 20, 2000, notice, the Agency found that Hg emissions from EGUs posed a hazard to public health and the environment. In making this finding, the Agency focused on the significant adverse health effects associated with MeHg and the persons most adversely impacted by Hg. The populations most affected were women of childbearing years and their developing fetuses and subsistence fishers. The Agency viewed the adverse health effects and environmental effects described above in conjunction with the then current Hg emissions information provided by EGUs in response to the 1999 ICR. Based on that information, EPA concluded that EGUs accounted for approximately 30 percent of the U.S. anthropogenic emissions of Hg, which translated into about 18 percent of the total Hg deposition in the U.S. at that time. EPA also knew that Hg from EGUs comprised an undetermined amount of the reemissions of Hg.

See

Mercury Study, Volume 3, page 2-3.

At the time of the December 2000 Finding, the Agency had issued section 112 or 129 standards for several of the other source categories that were significant Hg emitters, and the Agency was required by the CAA to establish section 112 or 129 standards for the other significant Hg emitters.

See

Standards for Large Municipal Waste Combustors, 40 CFR part 60, subpart Ea (NSPS), 56 FR 5507 (February 11, 1991), as amended, and 40 CFR part 60, subpart Eb (Emissions Guidelines), 60 FR 65419 (December 19, 1995), as amended; Standards for Medical Waste Incinerators, 40 CFR part 60, subpart Ec (NSPS), 62 FR 48382 (September 15, 1997), as amended, and 40 CFR part 60, subpart Ce (Emission Guidelines), 62 FR 48379 (September 15, 1997); Standards for Hazardous Waste Combustors, 40 CFR part 63, subpart EEE, 64 FR 53038 (September 30, 1999); Standards for Small Municipal Waste Combustors, 40 CFR part 60, subpart AAAA (NSPS), 65 FR 76355 (December 6, 2000), and 40 CFR part 60, subpart BBBB (Emissions Guidelines), 65 FR 76384 (December 6, 2000); and standard for Portland cement manufacturers (40 CFR part 63, subpart LLL, 64 FR 31925 (June 14, 1999)).

Most of these categories emitted far less Hg than EGUs at the time of the finding. Thus, at the time EPA made the December 2000 Finding, the record

reflected that Hg posed hazards to public health and the environment, that EGUs were the single largest unregulated domestic source of Hg emissions, and that HAP emissions from EGUs would remain unregulated absent listing under section 112. EPA reasonably found at the time that reducing Hg emissions from EGUs would further the goal of mitigating the hazards to public health and the environment posed by Hg.

The NESHAP for Portland cement did not include a standard for Hg when initially promulgated. In

National Lime Ass'n

EPA,

the DC Circuit Court held that section 112(d) contains a clear statutory directive to regulate all HAP emitted from a listed source category. 233 F.3d 624, 634 (DC Cir. 2000). EPA recently issued final section 112 standards for Portland cement manufacturers, including a standard for Hg emissions from such sources.

EPA also reasonably predicted that incremental reductions in Hg emissions, including from EGUs, would lead to incremental reductions in the MeHg concentration in fish tissue, and that such reductions would, in turn, reduce the risk to public health and the environment. 65 FR 79830. The Mercury Study recognized that Hg is a metal that remains in the environment permanently and can circulate continuously through various environmental media. Although EPA was aware that reductions of Hg from anthropogenic sources may not lead to immediate reductions in fish tissue levels, such reductions would nonetheless serve the long-term goal of reducing the mobilization of Hg to the atmosphere and thus reduce MeHg concentrations in fish.

EPA, therefore, reasonably determined based on the facts that existed at the time that regulation of EGUs was appropriate in order to reduce the hazards to public health and the environment associated with the Hg emissions from EGUs. EPA expressly acknowledged that there were uncertainties concerning the extent of the risk due to Hg emissions from EGUs, because the Agency had not quantified the amount of MeHg in fish that was directly attributable to EGUs compared to other sources of MeHg. 65 FR 79827. That EPA did not quantify in 2000 the amount of MeHg in fish due to EGUs did not preclude EPA from making an “appropriate” finding. Nowhere in section 112(n)(1) or in its direction concerning the NAS Study did Congress require EPA to quantify the amount of MeHg in fish tissue that was directly attributable to EGUs.

Moreover, EPA did not have sufficient confidence in its modeling tools at the time to draw conclusions about the contribution of specific source types to fish MeHg concentrations in specific geographic areas or nationally. These uncertainties are well described in the Utility, Mercury, and NAS Studies.

Consistent with section 112(n)(1), none of the studies addressed the amount of MeHg in fish attributable solely to EGUs. Instead, in the Utility and Mercury Studies, EPA discussed the significant contribution EGUs made to Hg deposition and that Hg deposition was problematic from a health and environmental standpoint. EPA submitted both the Utility Study and the Mercury Study to Congress by 1998. Aware of these studies, Congress, when directing the additional NAS Study, still did not require EPA to determine the amount of MeHg in fish due solely to EGUs. In light of this fact and the broad discretion Congress gave EPA to determine whether it was appropriate or necessary to regulate EGUs under section 112, EPA acted reasonably in 2000 by not delaying its finding several years to conduct an analysis of the portion of MeHg in fish due solely to EGUs.

In any event, in light of the breadth of the scientific evidence before the Agency and the conclusions the Agency reached, it would not have been reasonable to delay the finding to develop an analytical tool to apportion the Hg in fish. The Hg problem at the time was well documented, and the fact that EGUs represented such a significant portion of the Hg deposition in the U.S. was ample evidence that it was appropriate to regulate emissions from EGUs—the single largest unregulated domestic source of Hg emissions. 65 FR 79827.

Finally, the Agency had already delayed in completing the section 112(n)(1) studies. Additional delay would have been unreasonable because of the persistence of Hg in the environment and its tendency to bioaccumulate up the food chain, both aspects of Hg in the environment that make it critical to limit additional releases to the environment as quickly as possible. In addition, delay would have been unreasonable because EPA estimated at that time that about 7 percent of women of child-bearing age, one of the most at-risk populations, was exposed to Hg at levels exceeding the RfD, and EPA knew that as the level of exposure above the RfD increased, the level of risk and the extent and severity of adverse effects increased. Thus, EPA reasonably made the appropriate and necessary determination in 2000 to ensure that the largest unregulated domestic source of Hg would be required to install controls, thereby achieving an incremental reduction in the risk associated with a persistent, bioaccumulative HAP.

b. The Appropriate Finding for Non-Hg HAP Was Reasonable

The December 2000 Finding was also reasonable as it pertained to the non-Hg HAP emitted from EGUs. The Agency found it was appropriate to regulate EGUs based on the potential human health concerns from non-Hg HAP, particularly Ni from oil-fired EGUs, and the uncertainties regarding the public health impact of emissions of such HAP. 65 FR 79830. Based on the information in the Utility Study, EPA could not conclude based on the available information that the non-Hg HAP posed no hazards to public health.

Specifically, the Agency noted that several non-Hg HAP metals, including As, Cr, Ni, and Cd, were of potential concern for carcinogenic effects. 65 FR 79827. EPA acknowledged that the risks did not appear high, but it stated that the risks were not sufficiently low to disregard the metals as a potential concern for public health. 65 FR 79827;

see

Utility Study, Table 5-4, page 5-9 (finding cancer risks from oil-fired EGUs alone for Ni exceeded 1 in a million). The Agency also indicated that dioxins, HCl, and HF were of potential concern and might be evaluated further. 65 FR 79827.

EPA did not view the risks associated with non-Hg HAP in a vacuum. Rather, EPA considered the threat to public health, including uncertainties, associated with both Hg and non-Hg HAP emissions from EGUs in determining whether it was appropriate to regulate such units under section 112.

Finally, even looking solely at non-Hg HAP, EPA's conclusions support regulation of EGUs under section 112. Although Congress provided no metric for the hazard to public health determination, section 112(c)(9) is instructive. Specifically, in that section, Congress set forth a test for removing source categories from the section 112(c) source category list. That test is relevant because it reflects Congress' view as to the level of health effects associated with HAP emissions that Congress thought warranted regulation under section 112. If a source category failed to meet that test, it would remain subject to the requirements of CAA section 112. Thus, CAA section 112(c)(9) can be read to reflect Congress' view of what adverse public health effects from HAP emissions are acceptable and thus do not warrant regulation under CAA section 112.

For carcinogens, which are at issue here, section 112(c)(9)(B)(i) provides that EPA may delete a source category from the section 112(c) list if no source in the category (or group of sources in the case of area sources) emits such HAP in quantities that may cause a lifetime risk of cancer greater than one in one million to the individual in the population who is most exposed to emissions of such pollutants from the source (or group of sources in the case of area sources). Thus, section 112(c)(9)(B)(i) prohibits the Agency from delisting a major source category from the section 112(c) list if any single source within that category emits cancer causing HAP at levels that may cause a

lifetime cancer risk greater than one in one million to the most exposed individual. The Utility Study demonstrated that there were EGUs whose emissions resulted in a cancer risk greater than one in one million. Accordingly, it was reasonable to conclude at the time that non-Hg HAP emissions were of sufficient concern from a health perspective to warrant regulation.

3. EPA Reasonably Based the Appropriate Determination in Part on the Availability of Controls for HAP Emissions From EGUs

In addition to determining that it was appropriate to regulate because of the known and potential hazards to public health and the environment, EPA also concluded that it was appropriate to regulate HAP emissions from EGUs because EPA had identified a number of control options that would effectively reduce HAP emissions from EGUs. 65 FR 79828-30. EPA discussed the various controls available to reduce HAP emissions from EGUs in the December 2000 Finding. The approach of section 112, as amended in 1990, is based on the premise that, to the extent there are controls available to reduce HAP emissions, sources should be required to use them. Thus, it was reasonable to base the appropriate finding in part on the conclusion that controls currently available were expected to reduce HAP emissions from EGUs.

4. EPA Reasonably Concluded It Was Necessary To Regulate EGUs

In 2000, EPA found it was necessary to regulate HAP emissions from EGUs under section 112 because the imposition of the other requirements of the CAA would not address the serious public health and environmental hazards arising from such emissions. 65 FR 79830. EPA also noted that Congress enacted section 112 specifically to address HAP emissions from stationary sources, and it was thus reasonable to regulate HAP emissions from EGUs under that section given the hazards to public health and the environment posed by such emissions.

Id.

In Table 1 of the December 20, 2000 notice, EPA set forth its projections of HAP emissions for 2010. In assessing those projections in 2000, EPA considered the data that it had obtained as the result of the 1999 ICR. 65 FR 79828. It also considered projected changes in the population of units, fuel consumption, and control device configuration.

Id.

EPA considered control device configurations in making the 2010 projections, in an effort to account for the reductions attributable to the imposition of other requirements of the CAA.

Specifically, in estimating the projected 2010 HAP emissions from EGUs, EPA accounted for the HAP reductions that would occur as the result of the controls required to comply with the ARP. Congress added the ARP in CAA Title IV, as part of the 1990 amendments, and that program is primarily directed at EGUs. EPA, therefore, considered the HAP reductions projected to occur as the result of control configurations needed to meet the Acid Rain requirements of the CAA.

See, e.g.,

Utility Study, ES-2.

As shown in Table 1 of the December 20, 2000 notice, EPA estimated that the level of all HAP emitted by coal-fired EGUs would increase by 2010. 65 FR 79828 (Table 1). For Hg, EPA estimated that EGUs emitted 46 tons of Hg in 1990 and 43 tons of Hg in 1999, and it projected that EGUs would emit approximately 60 tons of Hg in 2010. 65 FR 79827-828. EPA also estimated an overall increase in non-Hg HAP emissions from coal-fired EGUs. Given these estimates and projections, which were based on the best information available at the time, EPA reasonably concluded that the identified and potential hazards associated with HAP from coal-fired EGUs would not be addressed through imposition of the other requirements of the CAA.

For oil-fired EGUs, EPA projected a decline in overall HAP emissions. The decline was primarily due to projected retirements and fuel switching from oil to natural gas. EPA could not conclude based on the information available at the time that the facilities posing the cancer risks, due primarily to Ni emissions, would retire or change fuels. As a result of these uncertainties and the uncertainties as to the extent of the public health impact from oil-fired units, EPA found that it was necessary to regulate such units under section 112.

5. The 2005 Action: EPA Erred in the 2005 Action by Concluding That the December 2000 Finding Lacked Foundation

In 2005, the Agency asserted that the December 2000 Finding lacked foundation for two reasons. First, the Agency stated that the 2000 appropriate finding was overbroad to the extent it relied on adverse environmental effects. Second, the Agency stated that the 2000 appropriate finding lacked foundation because EPA did not fully consider the Hg emissions remaining after imposition of the requirements of the CAA. For the reasons provided below, we reject these assertions as unfounded. As demonstrated above, EPA's 2000 appropriate and necessary finding was sound and fully supported by the record before the Agency in 2000.

a. Consideration of Environmental Effects in the Appropriate Finding

EPA reasonably examined the adverse environmental impacts associated with Hg in making the December 2000 Finding. In 2005, EPA changed its interpretation of the broad term “appropriate” to restrict the consideration of environmental effects only to situations where the Agency had determined that a hazard to public health exists as a

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