Draft Determination of Adequacy of Section 112 Authorities And Draft Determination of Need for Additional Standards

ENVIRONMENTAL PROTECTION AGENCY

[FRL-58536-3; Docket No. A-97-21]

RIN 2060-AH49

Draft Determination of Adequacy of Section 112 Authorities And

Draft Determination of Need for Additional Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of draft determinations.

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SUMMARY: Today's notice provides, for public comment, the EPA's draft

determinations that the legal authorities and mandates provided by

section 112 of the Clean Air Act (CAA) are adequate to prevent serious,

adverse, public health effects and serious or widespread environmental

effects associated with atmospheric deposition of hazardous air

pollutants to the Great Waters. Today's notice also provides EPA's

draft determination that, at this time, further emission standards or

control measures under section 112, beyond those otherwise authorized

by section 112, are not necessary and appropriate to prevent such

effects. These actions are being taken pursuant to section 112(m)(6) of

the CAA, as amended in 1990, and a consent decree entered in Sierra

Club v. Browner, Civ. No. 96-1680. Final determinations are required

under the consent decree to be made by March 15, 1998.

DATES: Written comments must be submitted by August 6, 1997.

ADDRESSES: Commenters must send an original and two copies of their

comments, referencing docket number A-97-21, to the Air Docket, U.S.

Environmental Protection Agency, 401 M Street, SW, Washington, DC

20460.

Comments and data may also be submitted electronically by following

the instructions under SUPPLEMENTARY INFORMATION of this document. No

Confidential Business Information (CBI) should be submitted through e-

mail.

FOR FURTHER INFORMATION CONTACT: Dianne Byrne, Office of Air Quality

Planning and Standards (MD-15), U.S. Environmental Protection Agency,

Research Triangle Park, North Carolina 27711, telephone number (919)

541-5342.

SUPPLEMENTARY INFORMATION:

Electronic Availability

The official record for this notice, as well as the public version,

has been established for this notice under docket number A-97-21

(including comments and data submitted electronically as described

below). A public version of this record, including printed, paper

versions of electronic comments, which do not include any information

claimed as CBI, is available for inspection from 8 a.m. to 4 p.m.,

Monday through Friday, excluding legal holidays. The official record is

located at the address in ADDRESSES at the beginning of this document.

Electronic comments can be sent directly to EPA at A-and-R-

D[email protected]. Electronic comments must be submitted as an

ASCII file avoiding the use of special characters and any form of

encryption. Comments and data will also be accepted on disks in Word

Perfect in 5.1 file format or ASCII file format. All comments and data

in electronic form must be identified by the docket number (A-97-21).

Electronic comments on this draft notice may be filed online at many

Federal Depository Libraries.

The information in this notice is organized as follows:

I. Background

II. Introduction

A. Statutory Requirements for Great Waters Program

B. Scope of Analysis

III. Statutory Analysis--Other Provisions Relative to section 112(m)

Mandate

A. Definition of Major Source

B. Definition of Adverse Environmental Effect

C. Listing of Pollutants

D. Listing of Sources

E. Regulations to Control Emissions of Pollutants

1. MACT and GACT Standards

2. Residual Risk Standards

F. Urban Area Source Program

G. Studies and Reports to Congress

1. Mercury

2. Electric Utilities

H. Solid Waste Incineration Units

IV. Determination of Adequacy and No Need for Further Regulations

I. Background

Pursuant to section 112(m)(6) of the CAA, EPA is submitting for

public comment a draft determination that the legal authorities and

mandates provided by section 112 of the CAA are adequate to prevent

serious, adverse, public health effects and serious or widespread

environmental effects associated with atmospheric deposition of

hazardous air pollutants (HAP) to the Great Waters. The EPA is also

submitting for public comment its draft determination that further

emissions standards or control measures under section 112(m)(6), beyond

those otherwise authorized or required by section 112, are not at this

time necessary or appropriate to prevent such effects. The bases for

these draft determinations are discussed in today's notice and are

briefly summarized below.

Section 112(m)(6) of the CAA requires that EPA determine whether

adequate authority exists within the provisions of section 112, other

than subsection (m)(6) to prevent serious, adverse, effects to public

health and serious or widespread environmental effects associated with

atmospheric deposition of HAP to the Great Waters. In conducting this

assessment, EPA reviewed the authorities granted by section 112, as

they may function to reduce adverse effects caused by deposition of HAP

to the Great Waters. It should be emphasized that this determination

pertains to the authority within the CAA to take actions as appropriate

to address the enumerated effects; it does not pertain to the efficacy

of prior or future actions. In addition, the scope of this

determination is focused on the authority within section 112 to address

those pollutants and sources that can be regulated under that section's

authority. As such, pollutants that are not listed as HAP, pursuant to

section 112(b), and source categories that could not be listed pursuant

to section 112(b) are not included within the scope of this

determination. While not part of this determination, it may be useful

to note that some unlisted pollutants that are pollutants of concern to

the Great Waters are regulated by other sections of the CAA (such as

nitrogen oxides which are regulated pursuant to sections 108, 109, 202,

and section 407). Similarly, source categories that are outside the

scope of section 112 can be regulated under other provisions of the CAA

(such as mobile sources regulated pursuant to section 202). Emissions

of the Great Waters' pollutants of concern that are addressed by other

statutes (e.g., wastewater discharges addressed by the Clean Water Act)

are also not within the scope of this adequacy determination.

Section 112 establishes a statutory scheme by which EPA is to

identify HAP which may cause or contribute to adverse effects to public

health or the environment, develop performance standards for the

control of emissions from stationary sources of such HAP (in addition

to the HAP listed by Congress in the CAA), and adjust these control

requirements as needed to address any remaining unacceptable risk that

may be present after sources have complied with the emission standards.

The types of adverse environmental effects to be prevented are defined

in the CAA and are broad in scope. An adverse environmental effect is

defined by section 112(a)(7) as ``any significant and widespread

adverse effect, which may reasonably be anticipated, to wildlife,

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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.''

Authorities provided by other provisions of section 112 that may be

particularly relevant to the Great Waters' pollutants and sources are

briefly summarized below. Section 112 authorizes EPA to:

--Identify and list any air pollutant that may cause adverse effects

due to atmospheric deposition (section 112(b)).

--Identify and list any stationary source category that emits

pollutants with the potential to cause adverse effects (section

112(c)).

--Establish a lesser quantity (e.g., below 10 tons per year for a

single pollutant) emission rate based on several factors, including

persistence and potential to bioaccumulate. Such emission rate, once

established, would replace the 10 ton per year rate, per pollutant,

that is otherwise used to define a major source (section 112(a)(1)).

--Establish test methods and analytic procedures for monitoring and

measuring emissions, ambient concentrations, deposition, and

bioaccumulation of HAP (section 112(b)(5)).

--List sources of 7 specific HAP to assure at least 90 percent of

emissions of each pollutant are subject to national emission standards

(section 112(c)(6)). These pollutants are of particular concern for the

Great Waters.

--Promulgate performance standards (section 112(d)) for major sources

and listed area sources. These standards are to reflect the maximum

degree of emission reduction that is achievable, taking into

consideration the cost of achieving such reduction, non-air quality

health and environmental impacts, and energy requirements. In addition,

these standards are to apply pollution prevention measures, processes,

methods, systems or techniques which reduce the volume of or eliminate

emissions through process changes, substitution of materials, enclosure

of systems or processes, and other measures.

--Require additional controls, as necessary to provide an ample margin

of safety to protect public health or to prevent an adverse

environmental effect. Authority to take action, as needed, to help

prevent the effects identified under section 112(m)(6) is provided by

the ``residual risk'' provision (section 112(f)).

--Complete and transmit to Congress two studies that are especially

relevant to the Great Waters program. The first is a study of mercury

emissions from electric utilities, municipal waste combustors, and

other sources, including smaller (i.e., area) sources. When the study

becomes final, the results will be helpful in prioritizing mercury

reduction strategies. The second study addresses the hazards to public

health expected to occur as a result of HAP emissions from electric

utilities. Section 112(n)(1)(A) further requires that EPA determine,

based on the results its study, whether regulations to reduce utility

emissions are warranted. This regulatory determination has not yet been

made (section 112(n)(1)).

Based on its analysis of these section 112 provisions, and on

current knowledge of emission sources, atmospheric transport and

deposition, and bioaccumulation, EPA believes that section 112

authority is adequate to prevent serious adverse effects to public

health and serious or widespread environmental effects associated with

the deposition of HAP to Great Waters. If the other authorities of

section 112 are found inadequate, section 112(m)(6) of the CAA provides

additional authority to EPA to adopt further emission standards or

other control measures not otherwise mandated or authorized by section

112, if necessary and appropriate, to fully comply with the protective

mandate of the Great Waters provisions. Since EPA believes that the

authorities in section 112 are adequate to prevent the enumerated

effects, EPA believes that it would not be appropriate, at this time,

to promulgate further emission standards or other control measures

under section 112(m)(6) to prevent such effects beyond those already

authorized or required by section 112. In making these draft

determinations, EPA is not determining that air deposition of HAP does

not currently cause or contribute to adverse effects to the public

health or the environment.

II. Introduction

There are three important prerequisites to EPA's ability to

identify the need for, and to develop, appropriate actions to address

adverse health and environmental effects associated with atmospheric

deposition of HAP. First, EPA must have adequate data and methods

(e.g., air emissions inventories, ambient and deposition sampling and

analysis techniques, and atmospheric fate and transport models) with

which to collect and analyze relevant information. Additionally, there

must be scientific support for the establishment of appropriate health

thresholds, dose-response relationships and effects mechanisms.

This information must be sufficient to support scientific and

policy judgments about those effects that should be considered

``serious adverse,'' in the case of human health, and ``serious or

widespread,'' in the case of environmental effects. Finally, the Agency

must have adequate legal authority to adopt regulations which can

effectively reduce the emissions of the pollutants of concern in order

to prevent such effects.

Much of the effort to evaluate the extent to which the first two

prerequisites (technical and science) have been met is summarized in

the first and second Reports to Congress, and EPA expects to continue

significant efforts to develop and improve our understanding of the

scientific and technical issues. Today's notice discusses the third

prerequisite to effective actions, that is, the adequacy of legal

authorities provided by section 112 to prevent the effects specified in

section 112(m)(6), and announces EPA's draft adequacy determination

under that subsection. In addition, today's notice announces EPA's

draft determination regarding whether additional emissions standards or

control measures under section 112, beyond those otherwise authorized

or required by section 112, are at this time necessary and appropriate

to prevent such effects.

A. Statutory Requirements for Great Waters Program

Section 112(m) of the CAA, as amended in 1990, 42 U.S.C. 7401 et

seq. establishes the Great Waters program under which EPA has ongoing

responsibilities to identify and assess the extent of atmospheric

deposition of HAP to the Great Lakes, Chesapeake Bay, Lake Champlain,

and coastal waters (Great Waters, (42 U.S.C. 7412(m)). As part of this

program, EPA is to monitor for atmospheric deposition of HAP in the

Great Waters, investigate the sources of HAP deposition, research the

relative contribution of atmospheric pollutants to total loadings in

the Great Waters, evaluate adverse effects to public health or the

environment caused by HAP deposition, assess the contribution of HAP

deposition to violations of water quality or drinking water standards,

and sample for HAP in

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biota, fish, and wildlife of the Great Waters, (42 U.S.C. 7412(m)(1)

(A)-(E)).1

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\1\ 42 U.S.C. 7412(m)(1) provides:

The Administrator, in cooperation with the Under Secretary of

Commerce for Oceans and Atmosphere, shall conduct a program to

identify and assess the extent of atmospheric deposition of

hazardous air pollutants (and in the discretion of the

Administrator, other air pollutants) to the Great Lakes, the

Chesapeake Bay, Lake Champlain and coastal waters. As part of such

program, the Administrator shall--

(A) monitor the Great Lakes, the Chesapeake Bay, Lake Champlain

and coastal waters, including monitoring of the Great Lakes through

the monitoring network established pursuant to paragraph (2) of this

subsection and designing and deploying an atmospheric monitoring

network for coastal waters pursuant to paragraph (4);

(B) investigate the sources and deposition rates of atmospheric

deposition of air pollutants (and their atmospheric transformation

precursors);

(C) conduct research to develop and improve monitoring methods

and to determine the relative contribution of atmospheric pollutants

to total pollution loadings to the Great Lakes, the Chesapeake Bay,

Lake Champlain, and coastal waters;

(D) evaluate any adverse effects to public health or the

environment caused by such deposition (including effects resulting

from indirect exposure pathways) and assess the contribution of such

deposition to violations of water quality standards established

pursuant to the Federal Water Pollution Control Act [33 U.S.C.A.

1251 et seq.] and drinking water standards established pursuant to

the Safe Drinking Water Act [42 U.S.C.A. 300f et seq.]; and

(E) sample for such pollutants in biota, fish, and wildlife of

the Great Lakes, the Chesapeake Bay, Lake Champlain and coastal

waters and characterize the sources of such pollutants.

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In addition, EPA is to provide periodic Reports to Congress

describing the results of any monitoring, studies, and investigations

conducted under the Great Waters program, addressing the same issues as

mentioned above, and describing any revisions to the requirements,

standards and limitations under the CAA or other Federal laws that are

necessary to protect the public health and environment from atmospheric

deposition (42 U.S.C. 7412(m)(5)).2 The Agency's

implementation of the Great Waters program to date is discussed in the

first two Reports to Congress issued under section 112(m)(5):

``Deposition of Air Pollutants to the Great Waters: First Report to

Congress'', EPA-453/R-93-055 (May 1994); and ``Deposition of Air

Pollutants to the Great Waters: Second Report to Congress'', EPA-453/R-

97-011 (June 1997). Copies of these reports can be obtained, as

supplies permit, from the Library Services Offices (MD-35), U.S.

Environmental Protection Agency, Research Triangle Park, North Carolina

27711, or, for a nominal fee, from the National Technical Information

Service, 5285 Port Royal Road, Springfield, Virginia 22161, phone: 1-

800-553-NTIS or 703-487-4650.

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\2\ 42 U.S.C. 7412(m)(5) provides:

Within 3 years of November 15, 1990, and biennially thereafter,

the Administrator, in cooperation with the Under Secretary of

Commerce for Oceans and Atmosphere, shall submit to the Congress a

report on the results of any monitoring, studies, and investigations

conducted pursuant to this subsection. Such report shall include, at

a minimum, an assessment of--

(A) the contribution of atmospheric deposition to pollution

loadings in the Great Lakes, the Chesapeake Bay, Lake Champlain and

coastal waters;

(B) the environmental and public health effects of any pollution

which is attributable to atmospheric deposition to the Great Lakes,

the Chesapeake Bay, Lake Champlain and coastal waters;

(C) the source or sources of any pollution to the Great lakes,

the Chesapeake Bay, Lake Champlain and costal waters which is

attributable to atmospheric deposition;

(D) whether pollution loadings in the Great lakes, the

Chesapeake Bay, Lake Champlain or coastal waters cause or contribute

to exceedances of drinking water standards pursuant to the Safe

Drinking Water Act [42 U.S.C.A. 300f et seq.] or water quality

standards pursuant to the Federal Water Pollution Control Act [33

U.S.C. 1251 et seq.] or, with respect to the Great lakes,

exceedances of the specific objectives of the Great Lakes Water

Quality Agreement; and

(E) a description of any revisions of the requirements,

standards, and limitations pursuant to this chapter and other

applicable Federal laws as necessary to assure protection of human

health and the environment.

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Finally, section 112(m)(6) requires that the Administrator

determine whether the other provisions of section 112 are adequate to

prevent serious, adverse effects to public health and serious or

widespread environmental effects, including such effects resulting from

indirect exposure pathways, associated with atmospheric deposition to

the Great Waters of HAP (and their atmospheric transformation products,

(42 U.S.C. 7412(m)(6)).3 In making this determination, EPA

is to take into consideration the tendency of HAP to bioaccumulate. If

EPA determines that the other provisions of section 112 are not

adequate, section 112(m)(6) provides that EPA must then promulgate, in

accordance with section 112, such further emission standards or control

measures as may be necessary and appropriate to prevent such effects,

including effects due to bioaccumulation and indirect exposure

pathways. Id. As an initial matter, EPA interprets this latter mandate

to be a requirement to determine, in the first instance, whether

additional controls are necessary and appropriate, rather than as an

absolute requirement to promulgate some additional controls. (See,

e.g., Environmental Defense Fund v. Thomas, 870 F.2d 892, 898-900 (2nd

Cir. 1989) (While district court did not have jurisdiction to compel

the Administrator to revise the national ambient air quality standards

(NAAQS), it did have jurisdiction to compel EPA to take some formal

action either revising the NAAQS or declining to revise them)).

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\3\ 42 U.S.C. 7412(m)(6) provides:

As part of the report to Congress, the Administrator shall

determine whether the other provisions of this section are adequate

to prevent serious adverse effects to public health and serious or

widespread environmental effects, including such effects resulting

from indirect exposure pathways, associated with atmospheric

deposition to the Great Lakes, the Chesapeake Bay, Lake Champlain

and coastal waters of hazardous air pollutants (and their

transformation products). The Administrator shall take into

consideration the tendency of such pollutants to bioaccumulate.

Within 5 years after November 15, 1990, the Administrator shall,

based on such report and determination, promulgate, in accordance

with this section, such further emission standards or control

measures as may be necessary and appropriate to prevent such

effects, including effects due to bioaccumulation and indirect

exposure pathways. Any requirements promulgated pursuant to this

paragraph with respect to coastal waters shall only apply to the

coastal waters of the States which are subject to section 7627(a) of

this title.

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B. Scope of Analysis

In reviewing the language of section 112(m)(6), it is significant

to note the CAA's specific reference to the ``other provisions'' of

section 112 in describing EPA's duty to assess its ability to prevent

the specified effects. This reference to the statutory authorities is

in contrast to a consideration of particular regulatory actions that

might be taken or have already been taken under those provisions, or of

their individual effectiveness. The EPA views this language as calling

for an analysis of the adequacy of the regulatory authorities and

mandates provided by section 112, rather than of specific actions which

might be taken pursuant to this section. In other words, EPA must

determine whether the authorities provided by these provisions can

adequately prevent the enumerated health and environmental effects. In

the event that EPA determines that they cannot, the CAA further

provides limited authority to adopt additional rules not specifically

mandated or authorized by the other provisions of section 112 as needed

to fully comply with section 112(m)(6)'s protective mandate. This

authority is limited by its terms to developing rules ``in accordance

with'' section 112; EPA may not act, pursuant to section 112(m)(6),

inconsistently with the requirements of, or outside the scope of,

section 112. This means that any additional regulations promulgated

pursuant to section 112(m)(6) could apply only to stationary sources of

HAP.

As noted above, EPA does not interpret this language as calling for

an analysis of the adequacy of specific rules or actions which have

been, or will be, taken pursuant to the provisions of section 112. That

is, based on the statutory language itself, for the

[[Page 36439]]

purposes of conducting the required analysis, EPA must presume that the

provisions will be implemented in ways which fully comply with the

substantive requirements of the appropriate subsections of section 112

and not speculate about what actual degree of emissions control results

from a specific rule adopted in accordance with section 112. The EPA's

interpretation of the scope of this analysis is supported by the dates

by which Congress anticipated that this determination and any further

regulations would be adopted, compared to the deadlines imposed under

the Act for full implementation of section 112. Section 112(m)(6)

provides that EPA was to make the determination in the Report to

Congress required by section 112(m)(5). The first Report to Congress

was due on November 15, 1993. The EPA was then required to promulgate

additional regulations, if any, based on the report and determination

by November 15, 1995. However, many of the deadlines for other actions

under section 112 do not fall until much later. By requiring that EPA

complete the process of making this determination and adopting further

standards or control measures within 5 years after November 15, 1990,

EPA presumes Congress knew that a large number of mandated emission

standards, programs, and regulations under section 112 would either not

yet be commenced, or would still be in the early stages of development.

Moreover, even those section 112 controls that had already been

promulgated would not yet have demonstrated either success or failure

at preventing adverse effects to the public health and environment.

Consequently, Congress could not have expected that EPA, at the time

this determination was due, would have sufficient information with

which to judge the actual scientific or technical adequacy of those

recently adopted or future actions or regulations to achieve specific

degrees of protection. Indeed, section 112(c)(6), which requires that

EPA identify the sources of seven specific pollutants which are of

primary concern for the Great Waters, requires only an identification

and listing of sources of those pollutants as of November 15, 1995, the

same date by which EPA must determine whether additional regulations

are necessary and appropriate. Standards to subject these sources to

regulations are not required under section 112(c)(6) to be established

until 5 years thereafter.

While on the surface there might appear to be some conflict between

the section 112(c)(6) and 112(m)(6) deadlines for regulatory action,

EPA believes this tension is reconciled by the Agency's interpretation

of its section 112(m)(6) duty to be to determine adequacy based solely

on an a priori statutory analysis; if after review of the section 112

authorities, EPA concludes that they are inadequate to prevent the

enumerated public health or environmental effects, EPA is required to

establish further regulations based partly on the conclusion that those

other authorities, when eventually implemented, cannot possibly prevent

those effects. In other words, EPA is required under section 112(m)(6)

to plug any gaps it identifies early. But, if the Agency concludes that

section 112 is adequate, the section 112(m)(6) ``duty'' to establish

further regulations is not triggered, and the ``conflict'' with other

provisions' deadlines for regulatory actions becomes moot.

One question that EPA must resolve in making its determination

under section 112(m)(6) concerns the sources of pollutants which are

transported through the atmosphere and the extent to which EPA's

determination must encompass all such sources. This issue is

potentially significant because available information indicates that,

in addition to domestic stationary sources of HAP emissions which may

be subjected to regulation under section 112, atmospheric deposition of

some HAP partially results from mobile source emissions, as well as

transport of emissions from foreign sources. Also, some HAP, which were

historically introduced to the environment by human activities, are

continually being recycled in the environment. That is, pollutants such

as PCBs, certain pesticides, and, to some extent, mercury, can

revolatilize from soils and waterbodies into the air, where they can be

transported downwind to new locations and redeposited, revolatilizing

again back into the air from these new locations and transporting

further downwind.

Nothing in the language of section 112(m)(6) suggests that the

Agency must consider these other sources in determining whether the

provisions of section 112 are adequate to prevent the adverse health or

environmental effects. That is, the statutory language does not extend

the scope of EPA's analysis to encompass impacts from HAP emissions

from sources that could not conceivably be subjected to section 112

regulation. Section 112(m)(6) goes on to provide that if EPA has

determined the other provisions of section 112 are inadequate, EPA must

promulgate additional necessary and appropriate emission standards or

other control measures ``in accordance with this section,'' i.e., in

accordance with section 112 (42 U.S.C. 7412(m)(6)). Section 112 does

not confer authority on the Agency to regulate mobile sources,

nondomestic sources of HAP emission, or contaminated sediments.

Instead, section 112, and the potential remedy to address an

``inadequacy'' determination under section 112(m)(6), is restricted in

application to stationary sources of HAP within the possible regulatory

reach of section 112. Moreover, EPA believes that Congress, in enacting

the section 112(m)(6) duty to evaluate the adequacy of section 112,

clearly understood that section 112, and the section 112 remedy

contained in section 112(m)(6), could only extend to stationary sources

already within the scope of the section. This is because it would have

been unnecessary to ask whether section 112 is adequate to control

sources that are clearly beyond its scope, such as mobile sources. For

these reasons, it is EPA's view that the scope of the section 112(m)(6)

determination should be limited to consideration of the adequacy of

section 112 provisions to prevent the enumerated adverse effects

associated with HAP emissions from sources which are within the scope

of EPA's authority to regulate under section 112. It is important to

note that it does not follow from this interpretation that in order to

determine that there are, or to address, adverse effects to public

health or serious or widespread effects to the environment under

section 112, EPA must consider only the contributions from domestic

stationary sources subject to regulation under section 112.

III. Statutory Analysis--Other Provisions Relative to Section 112(m)

Mandate

Among other things, section 112 establishes a statutory scheme

through which EPA is to identify HAP which present or may present a

threat of adverse human health effects or adverse environmental

effects, develop standards for the control of emissions from major

stationary and area sources of such HAP (and the HAP listed by Congress

in the CAA), and adjust these emission control requirements to address

any remaining unacceptable risk which may be present once sources have

complied with the emission standards. The following sections discuss

these provisions in further detail, describing the extent to which they

authorize or enable actions to prevent serious adverse public health

effects and serious or widespread environmental effects associated with

atmospheric HAP deposition to the Great Waters, as described in section

112(m)(6).

[[Page 36440]]

A. Definition of Major Source

Section 112(a) sets forth several definitions that partly define

the scope of EPA's regulatory authority under section 112. The

definition of ``major source'' at section 112(a)(1), for example,

functions in part to establish which types of stationary sources must

be subjected to the most stringent controls. In addition, however, it

provides authority to include more sources within the definition, and

thus allows EPA to subject additional sources to more stringent

controls than is otherwise required under section 112 (42 U.S.C.

7412(a)(1)).\4\ While a major source is initially defined to mean any

stationary source or group of stationary sources located within a

contiguous area and under common control that emits or has the

potential to emit, considering controls, in the aggregate, 10 tons per

year of any HAP or 25 tons per year of any combination of HAP, EPA may

establish a lesser quantity for a major source based on the potency of

the air pollutant, persistence, potential for bioaccumulation, other

characteristics of the air pollutant, or other relevant factors.

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\4\ 42 U.S.C. 7412(a)(1) provides:

The term ``major source'' means any stationary source or group

stationary sources located within a contiguous area and under common

control that emits or has the potential to emit considering

controls, in the aggregate, 10 tons per year or more of any

hazardous air pollutant or 25 tons per year or more of any

combination of hazardous air pollutants. The Administrator may

establish a lesser quantity, or in the case of radionuclides

different criteria, for a major source than that specified in the

previous sentence, on the basis of the potency of the air pollutant,

persistence, potential for bioaccumulation, other characteristics of

the air pollutant, or other relevant factors.

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Section 112(m)(6) requires EPA to consider the tendency of HAP to

bioaccumulate when making its determination as to the adequacy of

section 112 (42 U.S.C. 7412(m)(6)). Since section 112(a)(1) allows EPA

to base lesser quantity emission rates for defining major sources on

bioaccumulation and other relevant factors, the authority in section

112(a)(1) can be used, in concert with other provisions of section 112

as discussed below, to impose controls that could help prevent the

enumerated effects associated with atmospheric deposition of HAP to the

Great Waters.

B. Definition of Adverse Environmental Effect

Section 112(a)(7) defines ``adverse environmental effect'' to mean

``any significant and widespread adverse effect, which may be

reasonably 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'' (42 U.S.C. 7412(a)(7)). The EPA interprets the scope

of this term to apply as broadly as the language included in section

112(m)(6) requiring EPA to prevent serious or widespread environmental

effects associated with atmospheric deposition to the Great Waters of

HAP and their transformation products. The EPA notes that the language

of section 112(a)(7) and 112(m)(6) is different: where the former

refers to ``significant and widespread adverse effect,'' the latter

refers to ``serious or widespread environmental effects.''

The legislative history does not provide further clarification of

the reasons for the differences in the terminology used in these two

provisions or otherwise suggest that Congress intended for the two

phrases to have different meanings. Rather, references to the House

Amendments that became section 112(m)(6) indicate that the sponsors

understood the language in the Amendments to have the same meaning as

that used elsewhere in section 112 to describe ``adverse''

environmental effects. (See, e.g., remarks of Mr. Levine, House Debate

5-21-90, reprinted in A Legislative History of the Clean Air Act

Amendments of 1990, at 2633; Remarks of Mr. Bilirakis, House Debate 5-

23-90, id., at 2941; Remarks of Mr. Lagomarsino, House Debate 5-23-90,

id., at 2946; Remarks of Mr. Levine, House Debate 5-23-90, id., at

2938.) The EPA believes that these differences do not impose materially

different standards, and that for purposes of the section 112(m)(6)

determination, the standard imposed under section 112(a)(7) is

substantially the same as that in section 112(m)(6). This is because

EPA interprets section 112(m)(6) as directing EPA to assure that only

``adverse'' environmental effects from HAP deposition are prevented,

rather than effects that are not ``adverse,'' if any exist. In this

context, EPA believes that the differing language in the two

subsections functions interchangeably. (See, e.g., De Sylva v.

Ballentine, 351 U.S. 570 (1956) (``the word `or' is often used as a

careless substitute for the word `and,' that is, it is often used in

phrases where `and' would express greater clarity''); See also, U.S. v.

Moore, 613 F.2d 1029 (D.C. Cir. 1979); U.S. v. 1973 One Rol ls Royce,

43 F.3d 794 (3rd Cir. 1994); Kelly v. Wauconda Park Dist., 801 F.2d 269

(7th Cir. 1986); U.S. v. Smeathers, 884 F.2d 363 (8th Cir. 1989). While

the use of different terminology in ections 112(a)(7) and 112(m)(6)

does raise some ambiguity regarding Congress' intent, EPA believes that

the most reasonable way to resolve this ambiguity is to read the

slightly different language in section 112(m)(6) consistently with how

Congress defined environmental effects of concern for 11 other purposes

under section 112. (See Chevron U.S.A., Inc. v. NRDC, 467 U.S. 837

(1984).) Otherwise, under a literal reading, Congress might be viewed

as having charged EPA with the duty to prevent environmental effects

which by definition under section 112 are not ``adverse.'' The EPA does

not believe such a reading would make sense, either as a matter of

statutory interpretation or as a matter of environmental policy.

Moreover, other language in section 112(m) suggests that Congress

intended for the different terminology in section 112(a)(7) and

112(m)(6) to have the same meaning. In section 112(m)(1), the initial

subsection directing EPA to establish the Great Waters program,

Congress required EPA to evaluate ``any adverse effects to public

health or the environment caused by [HAP] deposition (including effects

resulting from indirect exposure pathways'' (42 U.S.C. 7412(m)(1)(D)).

This provision's use of the section 112(a)(7) defined the term

``adverse environmental effect,'' as inclusive of the same ``effects

resulting from indirect exposure pathways'' as defined in section

112(m)(6), indicates that Congress assumed the scope of environmental

impacts to be covered by section 112(a)(7) and 112(m)(6) would be the

same. Indeed, if Congress had thought otherwise, it would have been

unnecessary for it to have asked EPA to assess whether the other

substantive provisions of section 112 are adequate to prevent the

effects identified in section 112(m)(6). If the environmental effects

in section 112(m)(6) are by definition broader in scope than those

included in the definition of ``adverse environmental effects'' in

section 112(a)(7), the other provisions of section 112 would

necessarily be inadequate to prevent them, and no administrative

expertise on EPA's part would be needed in order to assess this.

While section 112(a)(7) provides as one example of an ``adverse

environmental effect,'' ``significant degradation of environmental

quality over broad areas,'' the use of the term ``widespread'' should

not be viewed as requiring in all cases an environmental effect to

occur in multiple geographic areas. For example, in other contexts, EPA

has interpreted ``widespread'' economic impacts as being those that

[[Page 36441]]

apply to a single affected community. (See EPA final rule, Water

Quality Standards Regulation, 48 FR 51400, 51401 (November 8, 1983); 40

CFR 131.10(g)(6).) In addition, section 112(a)(7) provides as another

example of ``adverse environmental effects'' impacts on populations of

endangered or threatened species; such populations are especially

likely to occur in limited geographic areas. EPA believes Congress did

not intend the ``widespread'' criterion to exclude impacts that might

occur within a limited geographic range that might include, for

example, one of the Great Lakes, the Chesapeake Bay, another Great

Waters waterbody, or a significant portion of such a waterbody. Thus,

to the extent that specific provisions in section 112, such as the

residual risk provisions in section 112(f), allow or require EPA to

prevent ``adverse environmental effects,'' this authority is adequate

to prevent the effects enumerated in section 112(m)(6).

C. Listing of Pollutants

Before EPA may adopt standards or other measures to prevent or

control emissions of a given pollutant under section 112, the pollutant

must first be formally listed as a HAP pursuant to section 112(b).

Section 112(b)(1) provides an initial list of 189 chemicals which

Congress concluded are HAP.\5\ Section 112(b)(2) also provides in part

that the Administrator shall periodically review the list and publish

the results thereof and, where appropriate, revise the list by rule,

adding pollutants which present, or may present, through inhalation or

other routes of exposure, a threat of adverse human health effects or

adverse environmental effects whether through ambient concentrations,

bioaccumulation, deposition, or otherwise (42 U.S.C. 7412(b)(2)).\6\

Section 112(b)(3)(B) further provides that EPA shall add substances to

the list, upon a showing by outside petitioners or on the Agency's own

determination, that ``the substance is an air pollutant and that

emissions, ambient concentrations, bioaccumulation or deposition of the

substance are known to cause or may reasonably be anticipated to cause

adverse effects to human health or adverse environmental effects'' (42

U.S.C. 7412(b)(3)). To assist the Agency in its efforts, section

112(b)(4) provides that, where information on the health or

environmental effects of a substance is not sufficient to make a

determination required by section 112(b), ``the Administrator may use

any authority available to the Administrator to acquire such

information'' (42 U.S.C. 7412(b)(4)). Moreover, section 112(b)(5)

allows EPA to establish, by rulemaking test measures and other analytic

procedures for monitoring and measuring emissions, ambient

concentrations, deposition, and bioaccumulation of hazardous air

pollutants (42 U.S.C. 7312(b)(5)).

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\5\ This list now contains 188 HAP, as a result of EPA's final

decision to remove the compound caprolactam from the section

112(b)(1) list. See 61 FR 30816 (June 18, 1996), codified at 40 CFR

63.60.

\6\ 42 U.S.C. 7412(b)(2) provides:

The Administrator shall periodically review the list established

by this subsection and publish the results thereof and, where

appropriate, revise such list by rule, adding pollutants which

present, or may present, through inhalation or other routes of

exposure, a threat of adverse human health effects (including, but

not limited to, substances which are known to be, or may reasonably

be anticipated to be, carcinogenic, mutagenic, teratogenic,

neurotoxic, which cause reproductive dysfunction, or which are

acutely or chronically toxic) or adverse environmental effects

whether through ambient concentrations, bioaccumulation, deposition,

or otherwise, but not including releases subject to regulation under

subsection (r) of this section as a result of emissions to the air.

No air pollutant which is listed under section 7408(a) of this title

may be added to the list under this section, except that the

prohibition of this sentence shall not apply to any pollutant which

independently meets the listing criteria of this paragraph and is a

precursor to a pollutant which is listed under section 7408(a) of

this title or to any pollutant which is in a class of pollutants

listed under such section. No substance, practice, process or

activity regulated under subchapter VI of this chapter shall be

subject to regulation under this section solely due to its adverse

effects on the environment.

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The EPA believes that, taken together, the provisions of section

112(b) discussed above provide adequate authority to identify and

formally list any HAP which has the potential for causing adverse

public health or environmental effects due to atmospheric deposition.

Of the 15 chemicals or chemical classes that have been identified as

pollutants of concern in the Great Waters program, 13 are already

listed as HAP. The two unlisted pollutants (or pollutant classes) are

nitrogen compounds and the pesticide, Dieldrin. The EPA has authority

to regulate emissions of nitrogen oxides under other sections of the

CAA (e.g., sections 108, 109, 129, 202, and 407). There are currently

no known air emission sources of Dieldrin in the United States. This

substance is a pollutant of concern because it continues to be measured

in the Great Waters at levels considered to be potentially harmful.

However, these levels are the result of prior use of the pesticide and

its recycling in the environment. Thus, there is currently no basis for

adding Dieldrin to the HAP list in section 112.

D. Listing of Sources

Once a pollutant has been listed as a HAP pursuant to section

112(b), EPA is required by section 112(c)(1) to publish and to

periodically review and revise a list of all categories and

subcategories of major sources and area sources of these pollutants (42

U.S.C. 7412(c)(1)).7 Section 112(c)(2) then requires EPA to

establish emissions standards under section 112(d) for the listed

categories and subcategories (42 U.S.C. 7412(c)(2)). Additionally,

section 112(c) imposes requirements to list categories or subcategories

of sources, including area sources, meeting certain specified criteria.

Significant to section 112(m) are the requirements of section

112(c)(6)--EPA is required to identify and to list categories and

subcategories of sources to assure that at least 90 percent of the

aggregate emissions of each of seven specific pollutants are subject to

emission standards under section 112 (d)(2) or (d)(4) and 42 U.S.C.

7412(c)(6)).8 These seven pollutants, alkylated lead

compounds, polycyclic organic matter, hexachlorobenzene, mercury,

polychlorinated biphenyls, 2,3,7,8-tetrachlorodibenzofurans and

2,3,7,8-tetrachlorobenzo-p-dioxin--are identified as pollutants of

concern to the Great Waters, and standards for them must be promulgated

by November 15, 2000.

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\7\ 42 U.S.C. 7412(c)(1) provides:

Not later than 12 months after November 15, 1990, the

Administrator shall publish, and shall from time to time, but no

less often than every 8 years, revise, if appropriate, in response

to public comment or new information, a list of all categories and

subcategories of major sources and area sources (listed under

paragraph (3)) of the air pollutants listed pursuant to subsection

(b) of this section. To the extent practicable, the categories and

subcategories listed under this subsection shall be consistent with

the list of source categories established pursuant to section 7411

of this title and part C of this subchapter. Nothing in the

preceding sentence limits the Administrator's authority to establish

subcategories under this section, as appropriate.

\8\ 42 U.S.C. 7412(c)(6) provides:

With respect to alkylated lead compounds, polycyclic organic

matter, hexachlorobenzene, mercury, polychlorinated biphenyls,

2,3,7,8-tetrachlorodibenzofurans and 2,3,7,8-tetrachlorodibenzo-p-

dioxin, the Administrator shall, not later than 5 years after

November 15, 1990, list categories and subcategories of sources

assuring that sources accounting for not less than 90 per centum of

the aggregate emissions of each such pollutant are subject to

standards under subsection (d)(2) or (d)(4) of this section. Such

standards shall be promulgated not later than 10 years after

November 15, 1990. This paragraph shall not be construed to require

the Administrator to promulgate standards for such pollutants

emitted by electric utility steam generating units.

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Moreover, section 112(c)(5) provides EPA with broad discretion to

list additional categories and subcategories of area sources of HAP any

time the Agency finds they present a threat of

[[Page 36442]]

adverse effects to human health or the environment, either in the

aggregate or individually (42 U.S.C. 7412(c)(5)).9 Finally,

section 112(c)(3) imposes two additional requirements on EPA. First,

EPA must list each category or subcategory of area sources (i.e.,

nonmajor stationary sources of HAP) which EPA finds presents a threat

of adverse effects to human health or the environment (by such sources

individually or in the aggregate) warranting regulation under section

112; and second, EPA must list, based on actual or estimated aggregate

emissions of a listed pollutant or pollutants, sufficient categories or

subcategories of area sources to ensure that area sources representing

90 percent of the area source emissions of the 30 HAP that present the

greatest threat to public health in the largest number of urban areas

are subject to regulation under section 112 (42 U.S.C.

7412(c)(3).10 These regulations must be promulgated by

November 15, 2000.

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\9\ 42 U.S.C. 7412(c)(5) provides:

In addition to those categories and subcategories of sources

listed pursuant to paragraphs (1) and (3), the Administrator may at

any time list additional categories and subcategories of sources of

hazardous air pollutants according to the same criteria for listing

applicable under such paragraphs. In the case of source categories

and subcategories listed after publication of the initial list

required under paragraph (1) or (3), emission standards under

subsection (d) of this section for the category or subcategory shall

be promulgated within 10 years after November 15, 1990, or within 2

years after the date on which such category or subcategory is

listed, whichever is later.

\10\ 42 U.S.C. 7412(c)(3) provides:

The Administrator shall list under this subsection each category

or subcategory of area sources which the Administrator finds

presents a threat of adverse effects to human health or the

environment (by such sources individually or in the aggregate)

warranting regulation under this section. The Administrator shall,

not later than 5 years after November 15, 1990, and pursuant to

subsection (k)(3)(B) of this section, list, based on actual or

estimated aggregate emissions of a listed pollutant or pollutants,

sufficient categories or subcategories of area sources to ensure

that area sources representing 90 percent of the area source

emissions of the 30 hazardous air pollutants that present the

greatest threat to public health in the largest number of urban

areas are subject to regulation under this section. Such standards

shall be promulgated not later than 10 years after November 15,

1990.

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In its use of the terms ``category'' and ``subcategory'' of

sources, the CAA does not provide definitive guidance and, thus, EPA's

discretion in how to apply those terms is broad. The CAA does provide

definitions of ``major,'' ``stationary'' and ``area'' sources, the

latter meaning any stationary source of HAP that is not a major source

and excluding motor vehicles or nonroad vehicles subject to title II of

the CAA (42 U.S.C. 7412(a)(2).) 11 Thus, section 112(c)

provides for the listing of stationary sources only and does not reach

such sources as motor vehicles, aircraft, nonroad engines or vehicles

such as locomotives.

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\11\ 42 U.S.C. 7412(a)(2) provides:

The term ``area source'' means any stationary source of

hazardous air pollutants that is not a major source. For purposes of

this section, the term ``area source'' shall not include motor

vehicles or nonroad vehicles subject to regulation under subchapter

II of this chapter.

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While this might appear to be a deficiency in the scope of section

112, to the extent that emissions from such sources can cause or

contribute to significant and harmful atmospheric deposition of HAP,

they can be regulated under other provisions of the CAA such that

section 112 is not necessarily rendered ``inadequate'' due to its focus

on stationary sources. For example, in the case of emissions from motor

vehicles, section 202(a)(1) requires EPA to promulgate emissions

standards for any air pollutants from new motor vehicles or their

engines which in the Administrator's judgment cause or contribute to

air pollution which may reasonably be anticipated to endanger public

health or welfare (42 U.S.C. 7521(a)(1)). In addition, section

211(k)(1) requires EPA to promulgate requirements for the reformulation

of gasoline to control toxic air pollutants from motor vehicles which

reflect the greatest degree of emission reduction achievable through

the reformulation of gasoline, taking into consideration cost and

various factors. ``Toxic air pollutants'' are defined to include

polcyclic organic matter (POM), a pollutant of concern for the Great

Waters (42 U.S.C. 7545(k)(1), (10)(C)). Finally, section 213(a)(4)

allows EPA to promulgate regulations applicable to emissions from

nonroad engines or vehicles, in addition to those covering ozone and

carbon monoxide, whenever the Administrator determines that those

emissions may reasonably be anticipated to endanger public health or

welfare (42 U.S.C. 7547(a)(4)).

Based on this analysis, EPA believes that its authority to list

stationary sources of the listed HAP is sufficiently comprehensive for

domestic stationary sources, including small stationary sources. The

EPA is not aware of any basis by which a category or subcategory of

stationary sources of a listed HAP that is of concern under the Great

Waters program could evade listing for regulation under section 112.

While this authority is limited to stationary sources and thus does not

authorize regulation of mobile sources under section 112, EPA's other

CAA authority provides sufficient authority to address HAP emissions

from nonstationary sources subject to the CAA such that the listing

provisions of section 112(c) are adequate for purposes of section

112(m)(6).

E. Regulations to Control Emissions of Pollutants

1. Maximum Achievable Control Technology and Generally Available

Control Technology Standards

Once a pollutant is formally listed under section 112(b), and EPA

has also listed the stationary source categories or subcategories of

that pollutant, the Agency is required by section 112(d)(2) to

promulgate regulations to establish emission standards requiring the

maximum degree of reduction in emissions of the HAP, including a

prohibition on such emissions where achievable, that the Administrator,

taking into consideration the cost of achieving these emission

reductions and any non-air quality health and environmental impacts and

energy requirements, determines is achievable for new or existing

sources in the category or subcategory to which the emission standard

applies (42 U.S.C. 7412(d)(2)).12 These standards are

referred to as MACT standards, and they must require application of

measures, processes, methods, systems or techniques which reduce the

volume of, or eliminate, emissions of HAP. Such reduction or

elimination of HAP may occur through process changes,

[[Page 36443]]

substitution of materials or other modifications, enclosing systems or

processes to eliminate emissions, and taking other specified measures.

Id.

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\12\ 42 U.S.C. Sec. 7412(d)(2) provides:

Emissions standards promulgated under this subsection and

applicable to new or existing sources of hazardous air pollutants

shall require the maximum degree of reduction in emissions of the

hazardous air pollutants subject to this section (including a

prohibition on such emissions, where achievable) that the

Administrator, taking into consideration the cost of achieving such

emission reduction, and any non-air quality health and environmental

impacts and energy requirements, determines is achievable for new or

existing sources in the category or subcategory to which such

emission standard applies, through application of measures,

processes, methods, systems or techniques including, but not limited

to, measures which--

(A) reduce the volume of, or eliminate emissions of, such

pollutants through process changes, substitution of materials or

other modifications,

(B) enclose systems or processes to eliminate emissions,

(C) collect, capture or treat such pollutants when released from

a process, stack, storage or fugitive emissions point,

(D) are design, equipment, work practice, or operational

standards (including requirements for operator training or

certification) as provided in subsection (h) of this section, or

(E) are a combination of the above.

None of the measures described in subparagraphs (A) through (D)

shall, consistent with the provisions of section 7414 of

this title, in any way compromise any United States patent or United

States trademark right, or any confidential business information, or

any trade secret or any other intellectual property right.

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Subsection 112(d)(3) goes on to establish that these emission

standards may not be less stringent than the emission control that is

achieved in practice by the best controlled similar source, in the case

of new sources; by the average emission limitation achieved by the best

performing 12 percent of the existing sources; or by the average

emission limitation achieved by the best performing five existing

sources, where there are fewer than 30 sources in the category or

subcategory, whichever is applicable (42 U.S.C. 7412(d)(3)).

13 Moreover, for source categories or subcategories of area

sources listed under section 112(c), section 112(d)(5) allows EPA, in

lieu of requiring MACT for such sources, to promulgate standards which

provide for the use of GACT) or management practices to reduce

emissions of HAP (42 U.S.C. 7412(d)(5)). Additional provisions are made

for emission standards for coke ovens, and an exclusion from regulation

is provided for radionuclides and their sources licensed by the Nuclear

Regulatory Commission if certain findings are made. Finally, section

112(d)(7) provides that any more stringent requirements or emissions

limitations established under provisions of the Act other than section

112 or under State authority are preserved (42 U.S.C. 7412(d)(7)).

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\13\ 42 U.S.C. Sec. 7412(d)(3) provides:

The maximum degree of reduction in emissions that is deemed

achievable for new sources in a category or subcategory shall not be

less stringent than the emission control that is achieved in

practice by the best controlled similar source, as determined by the

Administrator. Emissions standards promulgated under this subsection

for existing sources in a category or subcategory may be less

stringent than standards for new sources in the same category or

subcategory but shall not be less stringent, and may be more

stringent than--

(A) the average emission limitation achieved by the best

performing 12 percent of the existing sources (for which the

Administrator has emissions information), excluding those sources

that have, within 18 months before the emission standard is proposed

or within 30 months before such standard is promulgated, whichever

is later, first achieved a level of emission rate or emission

reduction which complies, or would comply if the source is not

subject to such standard, with the lowest achievable emission rate

(as defined by section 7501 of this title) applicable to the source

category and prevailing at the time, in the category or subcategory

for categories and subcategories with 30 or more sources, or

(B) the average emission limitation achieved by the best

performing 5 sources (for which the Administrator has or could

reasonably obtain emissions information) in the category or

subcategory for categories or subcategories with fewer than 30

sources.

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While section 112(d)(5) of the CAA allows EPA to restrict

application of MACT standards to major sources and to promulgate less

stringent GACT standards for area sources, the Agency is not required

to do so. As discussed earlier in this notice, although major sources

are defined as those which emit 10 tons per year or more of any HAP or

25 tons per year of any combination of HAP, EPA is granted discretion

under section 112(a)(1) to establish a lesser quantity emissions rate

(LQER) for a major source on the basis of the potency of the air

pollutant, persistence, potential for bioaccumulation, other

characteristics of the air pollutant, or other relevant factors (42

U.S.C. 7412(a)(1)). In addition, EPA interprets section 112(d)(5) as

authorizing the Administrator to establish GACT standards for area

sources when the imposition of MACT is determined to be unreasonable

(See 60 FR 4948, 4953, January 25, 1995). Thus, while EPA is permitted

by section 112(d)(5) to establish standards or requirements which

provide for the use of GACT or management practices to reduce emissions

of HAP, EPA retains discretion to subject area source categories or

subcategories to MACT where appropriate.

While the provisions of section 112(d) require EPA to focus the

potentially more stringent performance standards and control efforts on

major sources, they also allow EPA the discretion to apply these

requirements to smaller sources.

Section 112(e) establishes an aggressive schedule for establishing

section 112(d) standards. In addition to requiring all emission

standards for all categories and subcategories to be promulgated no

later than November 15, 2000, section 112(e)(2) requires EPA to

consider the known or anticipated adverse effects of HAP on public

health and the environment and other factors when determining

priorities for promulgating section 112(d) standards (42 U.S.C.

7412(e)(2)).

2. Residual Risk Standards

The Agency expects to achieve the vast majority of HAP emissions

reductions under section 112 through application of the section 112(d)

MACT and GACT programs. It must be stressed, however, that MACT and

GACT standards are not required to achieve a specified health-based

result or prevent specified environmental effects. Consequently,

section 112 provides another mechanism to address situations where

additional reductions are necessary to protect the public health or

prevent an adverse environmental effect, even after imposition of

controls such as MACT or GACT. The EPA is required by section

112(f)(2)(A) to promulgate more stringent standards within 8 years

after the adoption of the initial MACT standards, if such action is

necessary to provide an ample margin of safety to protect public health

or to prevent, taking into consideration costs, energy, safety, and

other relevant factors, an adverse environmental effect (42 U.S.C.

7412(f)(2)(A)).14 Whenever MACT standards under section

112(d) applicable to a source category or subcategory emitting a

pollutant classified as a known, probable or possible human carcinogen

do not reduce lifetime excess cancer risks to the individual most

exposed to emissions from a source in the category or subcategory to

less than one in one million, standards are required under section

112(f). If providing an ample margin of safety to protect public health

is not adequate to prevent an adverse environmental effect, a more

stringent standard must be promulgated. In addition, while section 112

does not require EPA to conduct residual risk analyses for GACT

standards, the Agency retains the discretion to establish residual risk

standards in appropriate cases after application of GACT. The EPA views

this provision as providing the Agency the authority to prevent any

remaining adverse environmental effect, as defined in section

112(a)(7), presented by HAP emissions from stationary sources after

[[Page 36444]]

imposition of controls under section 112(d).

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\14\ 42 U.S.C. Sec. 7412(f)(2)(A) provides:

If Congress does not act on any recommendation submitted under

paragraph (1), the Administrator shall, within 8 years after

promulgation of standards for each category or subcategory of

sources pursuant to subsection (d) of this section, promulgate

standards for such category or subcategory if promulgation of such

standards is required in order to provide an ample margin of safety

to protect public health in accordance with this section (as in

effect before November 15, 1990) or to prevent, taking into

consideration costs, energy, safety, and other relevant factors, an

adverse environmental effect. Emission standards promulgated under

this subsection shall provide an ample margin of safety to protect

public health in accordance with this section (as in effect before

November 15, 1990), unless the Administrator determines that a more

stringent standard is necessary to prevent, taking into

consideration costs, energy, safety, and other relevant factors, an

adverse environmental effect. If standards promulgated pursuant to

subsection (d) of this section and applicable to a category or

subcategory of sources emitting a pollutant (or pollutants)

classified as a known, probable or possible human carcinogen do not

reduce lifetime excess cancer risks to the individual most exposed

to emissions from a source in the category or subcategory to less

than one in one million, the Administrator shall promulgate

standards under this subsection for such source category.

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As discussed earlier in today's notice, for purposes of section 112

in general, the term ``adverse environmental effect'' is defined by

section 112(a)(7) to include ``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'' (42 U.S.C. 7412(a)(7)). Again,

EPA interprets the scope of this defined term to apply as broadly as

the effects discussed in section 112(m)(6). Moreover, section

112(f)(2)(A) allows the Agency to promulgate appropriate further

emissions standards for a source category or subcategory as necessary

to provide an ample margin of safety to protect public health or to

prevent any adverse environmental effect. Where the risk of harm to

public health or the risk of an adverse environmental effect is

presented by only certain sources within a source category or

subcategory, EPA believes it may appropriately tailor the section

112(f)(2) regulations applicable to the source category or subcategory

such that the requirement to achieve additional emissions reductions or

undertake other control efforts is imposed only on those sources within

the category or subcategory that present the risk. This approach would

avoid possible unnecessary imposition of these risk-based requirements

on any sources in the category or subcategory whose emissions do not

present such risk, and allow EPA to most effectively craft the section

112(f)(2)(A) requirements applicable to the category or subcategory to

specifically address the risks at issue. This interpretation is

supported by section 112(f)(2)(A)'s provision that EPA is authorized to

promulgate additional standards to prevent ``an'' adverse environmental

effect. The reference to ``adverse environmental effect'' in the

singular contemplates a situation where, for example, an adverse

environmental effect is presented by a limited number of sources within

a source category or subcategory, over a limited geographic or

situational range. Moreover, while EPA recognizes that section

112(f)(2)(A) requires the Agency to consider cost, energy, safety and

other relevant factors when establishing a more stringent limit than is

necessary to protect the public health with an ample margin of safety,

EPA has substantial discretion in determining how to evaluate those

factors and what weight to give them. (See, New York v. Reilly, 969

F.2d 1147, 1150 (D.C. Cir. 1992) (citing Center for Auto Safety v.

Peck, 751 F.2d 1336, 1342 (D.C, Cir. 1985), Weyerhaeuser Co. v. Costle,

590 F.2d 1011, 1045 (D.C. Cir. 1978)(Congress ``left EPA with

discretion to decide how to account for the consideration of factors,

and how much weight to give each factor'').) The presence of these

factors further supports EPA's view that it has substantial discretion

in developing the most appropriate approaches to addressing residual

risks presented by source categories or subcategories. For example, EPA

could use its section 112(f) residual risk authority to address adverse

environmental effects to Great Waters waterbodies that are associated

with the atmospheric deposition of HAP emitted by particular sources

within source categories.

In developing additional standards to address residual risk

following adoption of MACT standards, section 112(f) states that the

Administrator shall not be required to conduct any residual risk review

or promulgate additional emission limitations for any category or

subcategory of area sources that is listed under section 112(c)(3) for

which a GACT emission standard is promulgated pursuant to section

112(d)(5) (42 U.S.C. 7412(f)(5)).15 In effect, this

provision grants discretionary authority to EPA to provide an exemption

for area sources from the more stringent residual risk standards. It is

important to emphasize, however, that this exemption is wholly within

EPA's discretion so that, should the Agency determine that emissions of

one or more HAP from area sources within a source category or

subcategory pose unacceptable remaining risks to human health or the

environment, even after application of section 112(d) emission

controls, it has authority under section 112(f) to adopt more stringent

standards governing these sources as well. This is in addition to EPA's

discretionary authority to apply more stringent MACT standards to area

sources in the first instance. Thus, the CAA provides authority in

section 112(f)(2)(A) to take action with respect to stationary source

categories or subcategories as needed to prevent the same sorts of

effects identified under section 112(m)(6), and to focus such action so

that the duty to undertake measures in compliance with the residual

risk standard is triggered by sources within the subject category or

subcategory that present the risk of causing these effects.

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\15\ 42 U.S.C. 7412(f)(5) provides:

The Administrator shall not be required to conduct any review

under this subsection or promulgate emission limitations under this

subsection for any category or subcategory of area sources that is

listed pursuant to subsection (c)(3) of this section and for which

an emission standard is promulgated pursuant to section (d)(5) of

this section.

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F. Urban Area Source Program

Section 112(k) requires EPA to implement the urban area source

program. After conducting research to monitor, analyze and consider HAP

emissions from area sources in urban areas and their public health

risks, EPA is required under section 112(k)(3)(B)(I) to identify the 30

HAP emitted from area sources that present the greatest threat to

public health in the largest number of urban areas (42 U.S.C.

7412(k)(3)(B)(I)). The EPA must then identify the source categories for

listing under section 112(c), assuring that sources accounting for at

least 90 percent of the aggregate emissions of each of the 30

identified HAP will be subject to standards pursuant to section 112(d)

(42 U.S.C. 7412(k)(3)(B)(ii)).

Section 112(k)(3)(C) then requires EPA to prepare a strategy

including a schedule of specific actions to reduce public health risks

posed by emissions of HAP by area sources, which would be implemented

by EPA or the States under several Federal and State environmental

statutes. This strategy must achieve at least a 75 percent reduction in

the incidence of cancer attributable to exposure to HAP emitted by

stationary sources (42 U.S.C. 7412(k)(3)(C)). In addition to this

national urban area source strategy, EPA shall also encourage and

support areawide strategies developed by State and local agencies

intended to reduce risks from emissions by area sources in particular

urban areas, and prepare guidelines for control technologies or

management practices which may be applicable to various source

categories (42 U.S.C. 7412(k)(4)).

To the extent that the urban area source program identifies and

achieves reductions in HAP that are also pollutants of concern in the

Great Waters, section 112(k) provides an additional tool for reducing

HAP emissions that present serious adverse effects to the public health

or environment through atmospheric deposition. For example, this

program could result in significant reductions in emissions of POM,

with incidental benefits for the specific environmental values required

to be protected under the Great Waters provisions, if POM is identified

as one of the 30 most hazardous air pollutants emitted by area sources.

[[Page 36445]]

G. Studies and Reports to Congress

1. Mercury

Section 112(n)(1)(B) requires EPA to study and report to Congress

on mercury emissions from electric utility steam generating units,

municipal waste combustion units, and other sources, including area

sources (42 U.S.C. 7412(n)(1)(B)). 16 This study must

consider the rate and mass of such mercury emissions, the health and

environmental effects of the emissions, available technologies to

control these emissions, and the costs of applying such technology.

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\16\ 42 U.S.C. 7412(n)(1)(B) provides:

The Administrator shall conduct, and transmit to the Congress

not later than 4 years after November 15, 1990, a study of mercury

emissions from electric utility steam generating units, municipal

waste combustion units, and other sources, including area sources.

Such study shall consider the rate and mass of such emissions, the

health and environmental effects of such emissions, technologies

which are available to control such emissions, and the costs of such

technologies.

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When the report becomes final, the results of the study will be

helpful in prioritizing mercury reduction strategies.

2. Electric Utilities

Under section 112(n)(1)(A), EPA must also study and report to

Congress on the hazards to public health reasonably anticipated to

occur as a result of emissions of HAP by electric utility steam

generating units after imposition of the CAA requirements (42 U.S.C.

7412(n)(1)(A)).17 This report must develop and describe

alternative control strategies for emissions which may warrant

regulation under section 112, and EPA is required by section

112(n)(1)(A) to regulate electric utility steam generating units under

section 112 if EPA finds such regulation is necessary and appropriate

after considering the study.

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\17\ 42 U.S.C. 7412(n)(1)(A) provides:

The 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 report the results of this

study to the Congress within 3 years after November 15, 1990. The

Administrator shall develop and describe in the Administrator's

report to Congress alternative control strategies for emissions

which may warrant regulation under this section. 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.

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These provisions provide EPA the authority to achieve reductions in

HAP emissions from electric utilities as necessary and appropriate to

prevent reasonably anticipated hazards to public health and the

environment, which would have benefits for the Great Waters. For

example, if EPA determines that regulation of mercury emissions from

electric utilities is necessary and appropriate, EPA would have the

full set of regulatory tools available under section 112 to address

those emissions, including section 112(f), as well as any additional

alternative control strategies the Agency has identified in its Report

to Congress.

H. Solid Waste Incineration Units

Solid waste incineration units such as those that combust municipal

waste, medical waste, and industrial and commercial waste, are

regulated under sections 111 and 129 of the CAA. While this is not

literally a section 112 program, the types of standards to be applied

under section 129(a)(2) are MACT standards, and shall be based on

methods and technologies for removal or destruction of pollutants

before, during or after combustion. For new units, they must

incorporate siting requirements that minimize, on a site-specific

basis, to the maximum extent practicable, potential risks to public

health or the environment (42 U.S.C. 7429(a)(2), (3)).18

These standards are required for certain HAP (as well as specified

criteria pollutants) identified in section 129: solid waste

incineration units must be subjected to numerical emission limitations

for lead, cadmium, mercury, dioxins and dibenzofurans (42 U.S.C.

7429(a)(4)).19 Moreover, section 129(h)(3) requires EPA to

promulgate residual risk standards under section 112(f)(2) for

emissions of these pollutants from solid waste incineration units, if

such standards are required in order to provide an ample margin of

safety to protect the public health or to prevent an adverse

environmental effect as set forth in section 112(f)(2)(A) (42 U.S.C.

7429(h)(3)).20 Finally, State and local government agencies

are authorized under section 129(h)(1) to adopt and enforce

regulations, requirements, limitations or standards relating to solid

waste incineration units that are more stringent than those promulgated

by EPA (42 U.S.C. 7429(h)(1); (b)(2)).

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\18\ 42 U.S.C. 7429(a)(2) and (3) provide:

(2) Standards applicable to solid waste incineration units

promulgated under section 7411 of this title and this section shall

reflect the maximum degree of reduction in emissions of air

pollutants listed under section (a)(4) that the Administrator,

taking into consideration the cost of achieving such emission

reduction, and any non-air quality health and environmental impacts

and energy requirements, determines is achievable for new or

existing units in each category. The Administrator may distinguish

among classes, types (including mass-burn, refuse-derived fuel,

modular and other types of units), and sizes of units within a

category in establishing such standards. The degree of reduction in

emissions that is deemed achievable for new units in a category

shall not be less stringent than the emissions control that is

achieved in practice by the best controlled similar unit, as

determined by the Administrator. Emissions standards for existing

units in a category may be less stringent than standards for new

units in the same category but shall not be less stringent than the

average emissions limitation achieved by the best performing 12

percent of units in the category (excluding units which first met

the lowest achievable emissions rates 18 months before the date such

standards are proposed or 30 months before the date such standards

are promulgated, whichever is later).

(3) Standards under section 7411 of this title and this section

applicable to solid waste incineration units shall be based on

methods and technologies for removal or destruction of pollutants

before, during, or after combustion, and shall incorporate for new

units siting requirements that minimize, on a site specific basis,

to the maximum extent practicable, potential risks to public health

or the environment.

\19\ 42 U.S.C. 7429(a)(4) provides:

The performance standards promulgated under section 7411 of this

title and this section and applicable to solid waste incineration

units shall specify numerical emission limitations for the following

substances or mixtures: particulate matter (total and fine), opacity

(as appropriate), sulfur dioxide, hydrogen chloride, oxides of

nitrogen, carbon monoxide, lead, cadmium, mercury, and dioxins and

dibenzofurans. The Administrator may promulgate numerical emissions

limitations or provide for the monitoring of postcombustion

concentrations of surrogate substances, parameters or periods of

residence time in excess of stated temperatures with respect to

pollutants other than those listed in this paragraph.

\20\ 42 U.S.C. 7429(h)(3) provides:

The Administrator shall promulgate standards under section

7412(f) of this title for a category of solid waste incineration

units, if promulgation of such standards is required under section

7412(f) of this title. For purposes of this preceding sentence

only--

(A) the performance standards under subsection (a) of this

section and section 7411 of this title applicable to a category of

solid waste incineration units shall be deemed standards under

section 7412(d)(2) of this title, and

(B) the Administrator shall consider and regulate, if required,

the pollutants listed under subsection (a)(4) of this section and no

others.

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This program will result in significant reductions in emissions of

pollutants of concern for the Great Waters from solid waste

incineration units. Especially in light of the authority to subject

these units to residual risk standards under section 112(f)(2) and

EPA's substantial discretion afforded under that subsection, EPA

believes that it has adequate authority to prevent solid waste

incineration unit emissions of the specified HAP in section 129(a)(4)

from causing serious adverse public health and environmental effects

associated with deposition to the Great Waters.

IV. Determinations of Adequacy and No Need for Further Regulations

Based on available information and on the foregoing analysis,

guided by EPA's interpretation of the statutory

[[Page 36446]]

requirements of section 112(m), EPA believes that the other provisions

of section 112 are adequate to prevent serious, adverse effects to

public health and serious or widespread environmental effects

associated with the deposition of HAP which are emitted by stationary

sources for which EPA has authority and jurisdiction under section 112

to regulate. As a result, the Agency also believes that no further

emissions standards or control measures under section 112(m)(6), beyond

those authorized or required by the other provisions of section 112,

are necessary and appropriate at this time. The EPA further believes

that even if section 112 were found to be inadequate under section

112(m)(6), because much scientific information is still lacking

concerning such things as the relative contribution of air emissions of

pollutants of concern to adverse effects, it would not be possible at

this time for the Agency to conclude confidently that further

regulatory actions beyond those authorized or required to be taken

under section 112 are necessary and appropriate. The EPA solicits

comments on the draft determination, and on the analysis contained in

today's notice. The Agency reserves its right to reconsider these draft

determinations if the public comments on the draft determinations

convince EPA that it is incorrect in its analysis, or if future events

or additional information indicate EPA's determinations are not

accurate. In addition, when EPA finalizes these determinations, EPA

reserves its right to promulgate any necessary and appropriate further

regulations pursuant to section 112(m)(6), in the event that EPA in the

future, based on new information, revisits and reverses these

determinations.

The EPA is committed to continuing its analyses, research and

assessments of all aspects of atmospheric transport, deposition, fate

and effects of hazardous air pollutants emitted by section 112 sources.

The EPA is further committed to faithfully implementing the mandates

and authorities under section 112 of the CAA, and to pursuing other

available authorities, as appropriate, to minimize unreasonable threats

to humans and to the environment as a result of exposure to toxic

pollutants, whether such exposures result directly from emissions into

the air, through introduction to watersheds or waterbodies, or through

other pathways. The EPA will continue to work cooperatively with the

National Oceanic and Atmospheric Administration and the scientific

community to refine methods for measuring or estimating atmospheric

transport and deposition of HAP in order to more reliably characterize

and quantify the significance of atmospheric deposition to

environmental quality.

It is important to distinguish between EPA's draft determinations

in this notice and the Agency's judgments about the extent to which

adverse effects may be occurring due to atmospheric deposition of HAP

from all sources, or about the extent to which additional actions

within the scope of its other authorities under section 112 may be

warranted. In today's notice, EPA is announcing only that it believes

it has adequate authority under section 112 to prevent the section

112(m)(6) enumerated adverse health or environmental effects associated

with emissions of HAP from sources which section 112 was intended to

regulate, and that, at this time, EPA does not believe that further

emissions standards or control measures under section 112(m)(6) to

prevent such effects, beyond those that are authorized or required by

the other provisions of section 112, are necessary or appropriate for

stationary sources of HAP. These draft determinations in no way

represent a conclusion on EPA's part that air deposition of HAP does

not currently cause or contribute to adverse effects to the public

health or the environment.

Dated: June 30, 1997.

Carol Browner,

Administrator.

[FR Doc. 97-17597 Filed 7-3-97; 8:45 am]

BILLING CODE 6560-50-P