State Implementation Plans for Serious PM-10 Nonattainment Areas, and Attainment Date Waivers for PM-10 Nonattainment Areas Generally; Addendum to the General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[FRL-5052-2]

State Implementation Plans for Serious PM-10 Nonattainment Areas,

and Attainment Date Waivers for PM-10 Nonattainment Areas Generally;

Addendum to the General Preamble for the Implementation of Title I of

the Clean Air Act Amendments of 1990

AGENCY: Environmental Protection Agency (EPA).

ACTION: Addendum to General Preamble for future proposed rulemakings.

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SUMMARY: This addendum to the General Preamble for the Implementation

of Title I of the Clean Air Act Amendments of 1990 principally

describes EPA's preliminary views on how the Agency should interpret

various provisions of title I with regard to requirements for PM-10

(particles with an aerodynamic diameter less than or equal to a nominal

10 micrometers) serious nonattainment area State implementation plans

(SIP's). This document also addresses policy and guidance on attainment

date waivers potentially applicable to all areas that have been

designated nonattainment for PM-10, waivers of certain requirements

applicable to PM-10 serious nonattainment areas, and requirements for

international border areas in PM-10 nonattainment areas. Although the

guidance includes various statements that States must take certain

actions, these statements are made pursuant to EPA's preliminary

interpretations, and thus do not bind States and the public as a matter

of law. This addendum is an advance notice of how EPA generally intends

to take action on SIP submissions and to interpret various PM-10

related title I provisions.

FOR FURTHER INFORMATION CONTACT: Charlene E. Spells, Air Quality

Management Division, Mail Drop 15, Office of Air Quality Planning and

Standards, U.S. EPA, Research Triangle Park, North Carolina 27711,

(919) 541-5255.

ADDRESSES: References cited herein are available from the Public Docket

No. A-92-23. The docket is located at the Air and Radiation Docket and

Information Center, Room M-1500, Waterside Mall, Mail Code 6102, 401 M

Street SW., Washington, DC 20460. The docket may be inspected from 8:30

a.m. to 12 noon and from 1:30 p.m. to 3:30 p.m. on weekdays, except for

legal holidays. A reasonable fee may be charged for copying.

Supplementary Information:

Table of Contents

I. Introduction

II. Designations and Classifications

A. Designations

B. Classifications

C. Reclassifications

D. Appendix K and Waivers

III. International Border Areas

A. Statutory Requirement

B. Policy

IV. Serious Area SIP Requirements

V. Waivers for Certain PM-10 Nonattainment Areas

A. Historical Perspectives

B. Waiver Provisions

C. Application of Waiver Provisions

D. Waiver Policy Description

VI. Best Available Control Measures (BACM)

A. Requirement for BACM

B. EPA's Historical Interpretation of Control Technology

Terminology

C. BACM for Serious PM-10 Nonattainment Areas

D. Procedures for Determining BACM

E. Selection of BACM for Area Sources

F. Selection of Best Available Control Technology (BACT) for

Point Sources

VII. Contingency Measures

VIII. Quantitative Milestones and Reasonable Further Progress

A. General Discussion

B. Reasonable Further Progress

C. Quantitative Milestones

IX. Other Requirements

A. Executive Order 12866

B. Regulatory Flexibility Act

In accordance with 1 CFR 5.9(c), this document is published in the

proposed rules category.

I. Introduction

Issues are discussed in this document regarding policy and guidance

that will be applicable to areas that have been designated

nonattainment for PM-10 and reclassified as serious areas. This

document also discusses issues regarding policy and guidance on

attainment date waivers potentially applicable to all areas that have

been designated nonattainment for PM-10, as well as policy and guidance

on waivers of certain other requirements applicable to PM-10 serious

nonattainment areas, and requirements for international border areas in

PM-10 nonattainment areas.

Initially, all areas designated as nonattainment for PM-10 are

classified as moderate areas (see section 188(a) of the Clean Air Act

(Act)).\1\ Subsequently, in accordance with section 188(b) of the Act,

``The Administrator may reclassify as a serious PM-10 nonattainment

area * * * any area that the Administrator determines cannot

practicably attain the national ambient air quality standard for PM-10

by the attainment date (as prescribed in subsection (c)) for moderate

areas'' or any area that fails to timely attain. The EPA took final

action on January 8, 1993 to reclassify 5 moderate areas that were

initially designated as nonattainment for PM-10 upon enactment of the

1990 Amendments (see 58 FR 3334). The EPA is considering reclassifying

additional areas from moderate to serious.

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\1\The 1990 Amendments to the Clean Air Act made significant

changes to the air quality planning requirements for areas that do

not meet (or that significantly contribute to ambient air quality in

a nearby area that does not meet) the PM-10 national ambient air

quality standards (see Pub. L. No. 101-549, 104 Stat. 2399).

References herein are to the Clean Air Act, as amended, 42 U.S.C.

7401, et seq.

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This guidance document is being published as an addendum to the

General Preamble for the Implementation of Title I of the Clean Air Act

Amendments of 1990 (General Preamble) published April 16, 1992 (57 FR

13498).\2\ Among other things, this PM-10 nonattainment area guidance

document describes EPA's preliminary views on how EPA should interpret

various provisions of title I with regard to requirements for PM-10

serious area SIP's. Although the guidance includes various statements

that States must take certain actions, these statements are made

pursuant to EPA's preliminary interpretations, and thus do not bind the

States and the public as a matter of law. Of course, the use of

prescriptive language is appropriate in those instances where the

policy is simply reiterating statutory mandates which provide that

States must take certain actions.

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\2\A supplemental notice was published at 57 FR 18070, April 28,

1992, which provides certain appendices to the April 16, 1992

General Preamble. Subsequent references in this notice to the

General Preamble are inclusive of both documents.

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Possible approaches to implementing the provisions in section 179B

applicable to international border areas, general SIP requirements of

section 172(c), the specific requirements in subpart 4 of part D of

title I in serious PM-10 nonattainment areas, the issues involved and

the means of resolving those issues are discussed in the following

sections. The topics discussed include SIP requirements such as

provisions to assure that best available control measures (BACM) are

implemented; waivers for areas impacted by nonanthropogenic sources;

treatment of international border areas; requirements for quantitative

milestones, reasonable further progress (RFP) and contingency measures.

II. Designations and Classifications

A. Designations

Section 107(d) of the Act provides generally for the designation of

areas of each State as attainment, nonattainment or unclassifiable for

each pollutant for which there is a national ambient air quality

standard (NAAQS). Certain areas meeting the qualifications of section

107(d)(4)(B) of the Act were designated nonattainment for PM-10 by

operation of law upon enactment of the 1990 Amendments (initial PM-10

nonattainment areas). A Federal Register notice announcing all of the

areas designated nonattainment for PM-10 at enactment and classified as

moderate was published on March 15, 1991 (56 FR 11101). A follow-up

notice correcting some of these area designations was published August

8, 1991 (56 FR 37654). The nonattainment areas were formally codified

in 40 CFR part 81, effective January 6, 1992 (56 FR 56694, November 6,

1991). All those areas of the country not designated nonattainment for

PM-10 at enactment were designated unclassifiable (see section

107(d)(4)(B)(iii) of the Act).

B. Classifications

Once an area is designated nonattainment, section 188 of the Act

outlines the process for classification of the area and establishes the

area's attainment date. In accordance with section 188(a), all PM-10

nonattainment areas are initially classified as moderate by operation

of law upon their designation as nonattainment.

C. Reclassifications

1. General Conditions

A moderate area can subsequently be reclassified as a serious

nonattainment area under two general conditions. First, EPA has general

discretion under section 188(b)(1) to reclassify a moderate area as a

serious area at any time the Administrator determines the area cannot

practicably attain the NAAQS by the statutory attainment date for

moderate areas.\3\

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\3\The EPA's interpretation of the reclassification provisions

in section 188(b)(1) is discussed in detail in section III.C.1(b) of

the General Preamble (57 FR at 13537-38).

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Second, under section 188(b)(2) a moderate area is reclassified as

serious by operation of law after the statutory attainment date has

passed if the Administrator finds that the area has not attained the

NAAQS. The EPA must publish a Federal Register notice identifying the

areas that have failed to attain and were reclassified, within 6 months

following the attainment date (see section 188(b)(2)(B)).

2. Reclassification of Initial PM-10 Nonattainment Areas

Section 188(b)(1)(A) provides an accelerated schedule by which EPA

is to reclassify appropriate initial PM-10 nonattainment areas. The EPA

proposed on November 21, 1991 (56 FR 58656) to reclassify 14 of the 70

initial moderate areas as serious. The 14 areas EPA proposed to

reclassify were identified largely based on the magnitude and frequency

of ambient PM-10 measurements above the 24-hour NAAQS of 150 micrograms

per cubic meter (g/m3) during calendar years 1988-1990.

The EPA took final action on January 8, 1993 (58 FR 3334) to reclassify

5 of the 14 areas. The final decision to reclassify the 5 areas was

based on the criteria utilized in the proposal, comments received in

response to the proposal and on EPA's preliminary review of the SIP's

for the areas.

In the future, EPA anticipates that, generally, any decision to

reclassify an initial PM-10 nonattainment area before the attainment

date will be based on specific facts or circumstances demonstrating

that the NAAQS cannot practicably be attained in the area by December

31, 1994 (the statutory attainment date specified in section 188(c)(1)

for initial PM-10 nonattainment areas).

3. Reclassification of Future PM-10 Nonattainment Areas

Section 188(b)(1)(B) provides a timeframe within which EPA is to

reclassify appropriate areas designated nonattainment for PM-10

subsequent to enactment of the 1990 Amendments. Appropriate areas are

to be reclassified as serious within 18 months after the required date

for the State's submission of a moderate area PM-10 SIP.\4\ The statute

requires that these moderate area PM-10 SIP's be submitted within 18

months after the area is designated nonattainment (see section

189(a)(2)(B)). Taking these provisions together, the statute thus

requires that EPA reclassify appropriate PM-10 moderate areas

designated nonattainment after 1990 as serious within 3 years of such

designation.

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\4\This directive does not restrict EPA's general authority, but

simply specifies that it is to be exercised, as appropriate, in

accordance with certain dates.

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Because the moderate area SIP's are due before this

reclassification deadline, EPA anticipates that any determination that

such areas should be reclassified will be based upon facts contained in

the moderate area SIP demonstrating that the NAAQS cannot practicably

be attained by the statutory deadline. The EPA may also consider

reclassifying moderate areas for which a SIP has not been submitted

whenever it becomes apparent (e.g., because of an extensive delay in

submitting the SIP) that an area cannot practicably attain the

standards by the applicable attainment date. The EPA may also determine

that an area cannot practicably attain the standards by the applicable

date when the State submits an incomplete or otherwise inadequate SIP

for the area (i.e., a SIP which would not assure timely attainment) and

the State does not act expeditiously to correct such deficiencies.

The EPA does not believe that generally reclassifying moderate

areas as serious rewards areas which delay development and

implementation of PM-10 control measures. Rather, EPA believes its

policy creates an incentive for the timely submittal and effective

implementation of moderate area SIP requirements and facilitates the

PM-10 attainment objective. For example, if an area that fails to

submit a timely moderate area SIP is reclassified, this does not

obviate the requirement that the area submit and implement the moderate

area SIP requirements. Accordingly, in addition to reclassifying such

areas, EPA would also determine that the State had failed to submit a

PM-10 SIP and the area could be subject to sanctions under sections

110(m) and 179 for its delay. As provided under section 179(a) of the

Act, States containing areas for which EPA has made such determinations

have up to 18 months from EPA's determination to submit a complete plan

or plan revision before EPA is required to impose either the highway

funding sanction or the requirement to provide two-to-one new source

offsets described in section 179(b). If the deficiency has not been

corrected 6 months after the first sanction applies, then the second

sanction must apply.\5\ The EPA's determination also triggers a

requirement for EPA to impose a Federal implementation plan under

section 110(c)(1) of the Act. In conjunction with the possible

imposition of sanctions, EPA may issue a determination to reclassify

the area to serious.

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\5\See 58 FR 51270 (October 1, 1993).

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D. Appendix K and Waivers

Appendix K to 40 CFR part 50 provides guidance on the

interpretation of ambient air quality data to determine the air quality

status of an area. Appendix K and accompanying guidance (both preceding

the 1990 Amendments to the Act) provide in part that measured

exceedances of the PM-10 NAAQS which are believed to be influenced by

uncontrollable events caused by natural sources of particulate matter

or by events that are not expected to recur at a given location are

flagged and excluded from decisions as to whether or not the area

should be designated nonattainment.\6\ Therefore, if it is established

that exceedances are caused by natural sources, a State may be

permitted to avoid designating the area as nonattainment, even though

the exceedances are expected to recur.

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\6\See section 2.4 of appendix K of 40 CFR part 50 and ``The

Guideline on the Identification and Use of Air Quality Data Affected

by Exceptional Events,'' EPA-450/4-86-007, July 1986.

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The savings provision of section 193 of the amended Act provides,

among other things, that regulations and guidance promulgated or issued

by the Administrator prior to enactment of the 1990 Amendments are to

remain in effect according to their terms except to the extent that

they are inconsistent with any provision of the amended Act. Section

188(f) of the amended Act provides EPA with the discretionary authority

to waive a specific date of attainment for a PM-10 nonattainment area

where it is determined that nonanthropogenic sources contribute

significantly to the violation of the standard in the area, and to

waive certain nonattainment area SIP requirements where the

Administrator determines that anthropogenic sources of PM-10 do not

contribute significantly to the violation of the standard in the area.

These provisions take as a fundamental premise that areas experiencing

violations of the NAAQS due to nonanthropogenic sources are to be

designated as nonattainment. If areas were permitted to avoid being

designated as nonattainment because their violations are caused in

whole or part by uncontrollable natural events, then this statutory

provision would have to be read as having no legal effect or

significance. However, this would violate canons of statutory

construction, which direct that statutory language not be treated as

mere surplusage.

Consequently, although appendix K appears to be preserved in part

by section 193, the provision permitting the treatment of

``uncontrollable events caused by natural sources'' as exceptional

events, and therefore excludable from nonattainment decisions, is

inconsistent with the provisions of section 188(f) and should therefore

be regarded as no longer having legal effect. Similarly, any EPA

guidance permitting such exclusion of these events is inconsistent with

the amended Act. For this reason, exceedances which are attributable to

uncontrollable nonanthropogenic events may not be discounted or

deweighted in any manner, but must be fully considered in determining

whether violations of the NAAQS have occurred and whether designation

as nonattainment is warranted. Future determinations relevant to

exceptional events should therefore focus on the remaining type of

exceptional event identified under section 2.4 of 40 CFR part 50,

appendix K, namely whether the events--anthropogenic or

nonanthropogenic--are likely to recur at the same location.

The EPA plans to make perfunctory modifications to section 2.4 of

40 CFR part 50, appendix K. In addition, guidance on the interpretation

of air quality data believed to be influenced by special events and

conditions will be addressed in a separate publication that will

replace the 1986 Exceptional Events Guideline.

III. International Border Areas

A. Statutory Requirement

Section 818 of the 1990 Amendments added a new section, 179B, to

subpart 1, part D of title I. Section 179B applies to areas that could

attain the relevant NAAQS by the statutory attainment date but for

emissions emanating from outside the United States (U.S.). For PM-10

nonattainment areas, section 179B(a) provides that EPA must approve the

moderate area SIP if (1) the SIP meets all the applicable requirements

under the Act other than a requirement that such plan or revision

demonstrate attainment and maintenance of the PM-10 NAAQS by the

applicable attainment date, and (2) the State demonstrates to EPA's

satisfaction that the SIP would be adequate to attain and maintain the

PM-10 NAAQS by the attainment date but for emissions emanating from

outside the U.S. In addition, section 179B(d) provides that if a State

demonstrates that an area would have timely attained the PM-10 NAAQS

but for emissions emanating from outside the U.S., the area must not be

subject to the reclassification provisions of section 188(b)(2).

Section 188(b)(2) provides that any moderate PM-10 nonattainment area

that EPA determines is not in attainment after the applicable

attainment date shall be reclassified to serious by operation of law.

Therefore, the statute provides that areas that could attain but for

emissions emanating from outside the U.S. must not be reclassified as

serious after failing to attain by the applicable date.\7\

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\7\As noted, section 179B(d) states that areas demonstrating

attainment of the standards, but for emissions emanating from

outside the U.S., shall not be subject to section 188(b)(2)

(reclassification for failure to attain). By analogy to this

provision and applying canons of statutory construction, EPA will

not reclassify before the applicable attainment date areas which can

demonstrate attainment of the standards, but for emissions emanating

from outside the U.S. (see section 188(b)(1)). First, section 179B

evinces a general congressional intent not to penalize areas where

emissions emanating from outside the country are the but-for cause

of the PM-10 nonattainment problems. Further, if EPA were to

reclassify such areas before the applicable attainment date, EPA, in

effect, would be reading section 179B(d) out of the statute.

Specifically, if EPA proceeded to reclassify, before the applicable

attainment date, those areas qualifying for treatment under section

179B, an area would never be subject to the provision in section

179B(d) which prohibits EPA from reclassifying such areas after the

applicable attainment date. Canons of statutory construction counsel

against interpreting the law such that language is rendered mere

surplusage. Finally, note that section 179B(d) contains a clearly

erroneous reference to carbon monoxide instead of PM-10, and that

this section contains other clear errors (see, e.g., section 179B(c)

reference to section 186(b)(9), which does not exist).

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B. Policy

Assuming that a plan or revision meets all applicable requirements,

the State must show that an area is eligible to have its SIP approved

and not be reclassified as serious under section 179B by evaluating the

impact of emissions emanating from outside the U.S. and demonstrating

that the SIP would bring about attainment but for those emissions.

Several types of information may be used to evaluate the impact of

emissions emanating from outside the U.S. The EPA will consider the

information presented by the State for individual nonattainment areas

on a case-by-case basis in determining whether an area may qualify for

treatment under section 179B. Five examples of such information are

listed below in increasing order of sophistication (the State may use

one or more of these types of information or other techniques,

depending on their feasibility and applicability, to evaluate the

impact of emissions emanating from outside the U.S. on the

nonattainment area; the first three examples do not require the State

to obtain information from a foreign country):

1. Place several ambient PM-10 monitors and a meteorological

station, measuring wind speed and direction, in the U.S. nonattainment

area near the international border.\8\ Evaluate and quantify any

changes in monitored PM-10 concentrations with a change in the

predominant wind direction.

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\8\See 40 CFR part 58 for guidance on locating PM-10 monitors

and ``On-site Meteorological Program Guidance for Regulatory

Modeling Applications,'' EPA-450/4-87-013, June 1987 for guidance on

locating meteorological stations.

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2. Comprehensively inventory PM-10 emissions within the U.S. in the

vicinity of the nonattainment area and demonstrate that the impact of

those sources on the nonattainment area after application of reasonably

available controls does not cause the NAAQS to be exceeded. This

analysis must include an influx of background PM-10 in the area.

Background PM-10 levels could be based, for example, on concentrations

measured in a similar nearby area not influenced by emissions from

outside the U.S.

3. Analyze ambient sample filters for specific types of particles

emanating from across the border (although not required,

characteristics of emissions from foreign sources may be helpful).

4. Inventory the sources on both sides of the border and compare

the magnitude of PM-10 emissions originating within the U.S. to those

emanating from outside the U.S.

5. Perform air dispersion and/or receptor modeling to quantify the

relative impacts on the nonattainment area of sources located within

the U.S. and of foreign sources of PM-10 emissions (this approach

combines information collected from the international emission

inventory, meteorological stations, ambient monitoring network, and

analysis of filters).

In addition to demonstrating that the SIP for the area would be

adequate to timely attain and maintain the NAAQS but for emissions

emanating outside the U.S., the SIP must continue to meet all

applicable moderate area SIP requirements in order to qualify for the

special SIP approval under section 179B. Among other things, the SIP

must provide for the implementation of reasonably available control

measures (RACM), including reasonably available control technology

(RACT) (see 57 FR 13540). In international border areas, RACM/RACT must

be implemented to the extent necessary to demonstrate attainment by the

applicable attainment date if emissions emanating from outside the U.S.

were not included in the analysis. The EPA believes that this

interpretation of the degree of RACM the State is required to implement

in moderate PM-10 areas affected by emissions emanating from outside

the U.S. is consistent with the purpose of section 179B. By directing

EPA, under section 179B, to approve the plan or plan revision of a

moderate PM-10 area which shows it would attain the NAAQS but for

foreign emissions and by excluding such an area from reclassification

to serious, Congress clearly wanted to avoid penalizing States

containing such areas by not making them responsible for control of

emissions emanating from a foreign country over which they have no

jurisdiction. Moreover, by excluding the area from reclassification,

Congress also elected to avoid subjecting such areas to the more

stringent control measures applicable in serious PM-10 areas. In

addition, as set forth in section 179B(a)(2), the second condition

which must be met before EPA may approve a moderate area plan showing

attainment but for foreign emissions, by its plain terms, requires the

State to establish only that the plan submitted would be ``adequate''

to timely attain and maintain the NAAQS, but for emissions from outside

the U.S. Nothing in section 179B relieves the State from meeting all

its applicable moderate area PM-10 SIP requirements, including the

requirement to implement RACM. Nonetheless, if, in doing so, States

containing such an area were also required, because of contributions to

PM-10 violations caused by foreign emissions, to shoulder more of a

regulatory and economic burden than States not similarly affected

(i.e., by implementing measures which go well beyond those which the

SIP demonstrates would otherwise be adequate to timely attain and

maintain the PM-10 NAAQS) such a requirement would unfairly penalize

States containing international border areas and effectively undermine

the purpose of section 179B. Indeed, to the extent an affected State

can satisfactorily demonstrate that implementation of such measures

clearly would not advance the attainment date, EPA could conclude they

are unreasonable and hence do not constitute RACM. Notwithstanding the

above, in light of the overall health and clean air objectives of the

Act, EPA does encourage affected States to reduce emissions beyond the

minimum necessary to satisfy the ``but for'' test in order to reduce

the PM-10 concentrations to which their populations are exposed.

The SIP for an international border area must also include

contingency measures as required under section 172(c)(9) of the Act.

Under section 179B(a)(1), such SIP's must meet ``all the requirements

applicable to it under the Act'' except that they may demonstrate

timely attainment by discounting emissions emanating from outside the

U.S. Contingency measures are additional measures included in the SIP

that can be undertaken to reduce emissions if the area fails to make

RFP or to attain the primary NAAQS by the applicable attainment date.

In international border areas, EPA will not require the contingency

measures for PM-10 to be implemented after the area fails to attain if

EPA determines that the area would have attained the NAAQS, but for

emissions emanating from outside the U.S. However, the EPA will require

contingency measures to be implemented if it determines that the area

failed to make RFP in achieving the required reductions in PM-10

emissions from sources within the U.S., or if the area does not, in

fact, obtain the emission reductions that were necessary to demonstrate

timely attainment of the NAAQS, but for emissions emanating from

outside the U.S.

IV. Serious Area SIP Requirements

The Act requires States to submit several SIP revisions, as

necessary, providing for implementation of increasingly stringent

control measures and demonstrating when those control measures will

bring about attainment of the PM-10 NAAQS. The first SIP revision was

due November 15, 1991 for the initial moderate PM-10 nonattainment

areas. For areas redesignated nonattainment for PM-10 in the future

under section 107(d)(3), the first SIP revision will be due within 18

months after the area is redesignated (see section 189(a)(2)). This SIP

revision must, among other things, provide for implementation of RACM

on sources in the area (see sections 189(a)(1)(C) and 172(c)(1)). All

available technologically and economically feasible control measures

would be considered RACM, and therefore reasonable for adoption, for

areas that cannot attain the NAAQS by the applicable attainment date

(December 31, 1994 for initial moderate PM-10 nonattainment areas) (see

57 FR 13544).9

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\9\Note that if it can be shown that measures are unreasonable

because emissions from the sources affected are insignificant or de

minimis, such measures may be excluded from consideration as they

would not represent RACM for that area (see 57 FR 13540). Moreover,

in international border areas, measures which go beyond those which

the SIP demonstrates would be adequate to attain and maintain the

standard, but for emissions emanating from outside the U.S., would

not be considered ``reasonably'' available--and therefore would not

be required by RACM--since they would not advance the attainment

date (although States may elect to implement such measures in order

to reduce the public's exposure to PM-10) (see discussion under

International Border Areas of this guidance document).

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If EPA determines that a moderate area cannot practicably attain

the NAAQS by the applicable attainment date (or determines the area has

failed to attain) and reclassifies the area as a serious nonattainment

area under section 188(b), a second SIP revision for the area is

required under section 189(b). This revision must, among other things,

include provisions to assure that BACM (including BACT) will be

implemented in the area (see section 189(b)(1)(B)). In addition, a

demonstration (including air quality modeling) must be submitted

showing that the plan will attain the NAAQS either by the applicable

attainment date or, if an extension is granted under section 188(e), by

the most expeditious alternative date practicable (see section

189(b)(1)(A)).

The SIP revisions to require the implementation of BACM must be

submitted to EPA within 18 months after an area is reclassified as

serious (see section 189(b)(2)). The BACM are to be implemented no

later than 4 years after an area is reclassified (see section

189(b)(1)(B)). The EPA's policies regarding the requirement to

implement BACM in serious areas are discussed in section VI of this

document.

The serious area attainment demonstration required under section

189(b)(1)(A) must be submitted to EPA within 4 years after an area is

reclassified based on a determination by EPA that the area cannot

practicably attain the NAAQS by the statutory deadline for moderate

areas. It is due within 18 months after an area is reclassified for

actually having failed to attain the NAAQS by the moderate area

attainment date (see section 189(b)(2)).

The new attainment date for initial PM-10 nonattainment areas that

are reclassified as serious is to be as expeditious as practicable but

not later than December 31, 2001. For areas that are designated

nonattainment for PM-10 in the future and subsequently become serious,

the attainment date is to be as expeditious as practicable but no later

than the end of the tenth calendar year beginning after the area's

designation as nonattainment (see section 188(c)(2)).

If the State demonstrates to the satisfaction of EPA that

attainment by the statutory deadline for serious areas (as set forth in

section 188(c) of the Act) is impracticable, the State must demonstrate

that the SIP provides for attainment by the most expeditious

alternative date practicable. The State may apply to EPA for a single

extension of the serious area attainment date, under section 188(e) of

the Act, not to exceed 5 years beyond the serious area attainment date.

A State requesting an extension under section 188(e) for an area must,

among other things, demonstrate that the plan for the area includes the

most stringent measures that are included in the implementation plan of

any State or are achieved in practice in any State, and can feasibly be

implemented in the area. The EPA intends to issue guidance in the

future, as appropriate, on applying for an extension of the serious

area attainment date.

If a serious area fails to attain by the applicable attainment date

(which may be an extended attainment date), another SIP revision is

required within 12 months that provides for attainment and until then

for annual reductions in PM-10 or PM-10 precursor emissions within the

area of not less than 5 percent of the amount of such emissions as

reported in the most recent emission inventory for the area (see

section 189(d)).

In addition to the specific PM-10 SIP requirements contained in

subpart 4 of part D, title I, States containing serious areas must meet

all of the applicable general SIP requirements set forth in section

110(a)(2) and the nonattainment area SIP requirements set forth in

subpart 1 of part D, title I, to the extent that these provisions are

not otherwise subsumed by, or integrally related to, the more specific

PM-10 requirements.10 The general SIP requirements applicable to

all nonattainment areas are discussed in the General Preamble at 57 FR

13556-13557.

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\1\0See 57 FR 13538 (April 16, 1992).

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The requirements specifically applicable to serious areas under

subpart 4 are found primarily in section 189. Those requirements

include:

a. Current actual and allowable emissions inventories that meet EPA

guidelines11 (see section VI.D. below).

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\1\1``PM-10 Emission Inventory Requirements,'' EPA-450/2-93-XX,

U.S. Environmental Protection Agency, Research Triangle Park, NC,

1993.

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b. Submission of a SIP, under section 189(b)(1)(A), that includes a

demonstration that the plan provides for attainment by the applicable

attainment date (December 31, 2001 for the areas initially designated

nonattainment for PM-10 by operation of law under section 107(d)(4) and

no later than the end of the tenth year beginning after the area's

redesignation for areas subsequently redesignated nonattainment), or a

demonstration that attainment by the above date is not practicable and

that the plan provides for attainment by the most expeditious

alternative date practicable.12

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\1\2Subsequent to adopting requirements for BACM shortly after

the nonattainment area is reclassified as serious, it may be

necessary for the State to adopt additional control measures in

order to demonstrate that the SIP provides for attainment of the PM-

10 NAAQS in accordance with section 189(b)(1)(A)(i). If the State

demonstrates, in accordance with section 189(b)(1)(A)(ii), that

attainment by the applicable serious area attainment date is

impracticable and seeks an extension of the attainment date pursuant

to section 188(e), the State must demonstrate to the best of its

ability that the plan for the area includes the most stringent

measures that are included in the implementation plan of any State

or are achieved in practice in any State, and can be feasibly

implemented in the area.

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c. Provisions, under section 189(b)(1)(B), to assure that BACM

(including BACT) will be implemented no later than 4 years after the

area is reclassified as serious.

d. A requirement, under section 189(b)(3), that the terms ``major

source'' and ``major stationary source,'' used in implementing a new

source permitting program under section 173 and control of PM-10

precursors under section 189(e), include 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, at least 70 tons per

year of PM-10.

e. Contingency measures13 (see section VII. below).

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\1\3Contingency measures are other available control measures,

in addition to those in the control strategy to attain the NAAQS,

that can be implemented if EPA determines the area fails to make

reasonable further progress or to attain the NAAQS by the applicable

attainment date [see section 172(c)(9)).

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f. Quantitative milestones, (applicable to both moderate and

serious area SIP's under section 189(c)), which are to be achieved

every 3 years until the area is redesignated attainment, and which

demonstrate RFP toward attainment by the applicable date. The provision

includes a requirement for periodic reports demonstrating whether the

milestones have been met (see section VIII. below).

g. Plan revisions which provide for attainment of the PM-10 NAAQS

and annual reductions of not less than 5 percent of inventoried PM-10

and PM-10 precursor emissions within the area, under section 189(d), if

the serious area fails to attain the standards.

h. As applicable, RACT-level, BACT-level, and new source review

control of PM-10 precursors from major stationary sources of precursors

in the airshed (applicable to both moderate and serious area SIP's

under section 189(e)).

The demonstration required under section 189(b)(1)(A) should follow

the existing modeling guidelines addressing PM-10 (e.g., ``PM-10 SIP

Development Guideline'' (June 1987); ``Guideline on Air Quality

Models'' (Revised); memorandum from Joseph Tikvart and Robert Bauman

dated July 5, 1990) and any applicable regulatory requirements. A

supplementary attainment demonstration policy applicable to initial

moderate PM-10 nonattainment areas facing special circumstances was

issued in a memorandum from EPA's Office of Air Quality Planning and

Standards to the Directors of EPA Regional Air Divisions on March 4,

1991.14 That supplementary policy is not applicable to serious

area SIP demonstrations.

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\1\4``PM-10 SIP Attainment Demonstration Policy for Initial

Moderate Nonattainment Areas,'' memorandum from John Calcagni and

William Laxton to Director, Air Division, EPA Regions I-X, March 4,

1991.

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V. Waivers for Certain PM-10 Nonattainment Areas

A. Historical Perspectives

The EPA in the past focused much of its air pollution control

efforts on industrial point source emissions and other traditional

sources of air pollution.15 For instance, EPA's 1977 guidance on

SIP development gave priority to control of urban fugitive dust after

control of traditional sources, but in preference to rural fugitive

dust, on the grounds that (1) urban soil was believed to be

contaminated and, therefore, potentially more harmful than the native

soils in rural areas; (2) the potential for significant population

exposures and attendant health effects was much greater in urban areas;

and (3) scarce resources at the Federal, State, and local agency levels

could be most effectively brought to bear on the more pronounced

problems found in urban areas.16 Accordingly, EPA's policy was to

require greater emphasis on control of emissions in urban areas,

including control of fugitive dust from all major sources. In contrast,

control requirements for rural areas were far less ambitious, focussing

on the control of major industrial sources, with little attention given

to natural or nonindustrial emissions. This policy of giving a lower

priority to controlling natural or nonindustrial emissions in rural

areas became known as the ``Rural Fugitive Dust Policy.''17

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\1\5The EPA distinguished between ``traditional'' and

``nontraditional'' sources. The term ``nontraditional source'' first

appeared in official print in 1976 in EPA's ``National Assessment of

the Urban Particulate Problem,'' EPA-450/3-76-024, July 1976, and

was coined as a catch-all to refer to those sources not

traditionally considered in air pollution control strategies,

including construction and demolition, tailpipe emissions, tire

wear, and various sources of fugitive dust. Since then, the use of

the term has expanded to include such sources as prescribed

agricultural and silvicultural burning, open burning, and

residential wood combustion.

\1\6''Guidance on SIP Development and New Source Review in Areas

Impacted by Fugitive Dust,'' Edward F. Tuerk, Acting Assistant

Administrator for Air and Waste Management, to Regional

Administrators.

\1\7See, e.g., ``Model Letter Regarding State Designation of

Attainment Status,'' David H. Hawkins, Assistant Administrator for

Air and Waste Management, to Regional Administrators, October 7,

1977; see also, ``Fugitive Dust Policy: SIP's and New Source

Review'' (August 1984).

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The EPA's policy focus shifted away from the type and location of

the emission sources (i.e., traditional or nontraditional sources,

urban or rural locations) to the size of the particles emitted when the

indicator for the NAAQS was changed in 1987 from total suspended

particulate matter to PM-10. While revisions to the rural fugitive dust

policy were being considered, the policy was continued during the

initial phases of implementing the PM-10 NAAQS on an interim

basis.18 However, EPA believes that the 1990 Amendments provide a

statutory alternative that wholly supplants the rural fugitive dust

policy (see sections 107(d)(4)(B) and 188(f) of the amended Act; 56 FR

37659 (August 8, 1991)).

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\1\8See 52 FR 24716 (July 1, 1987).

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B. Waiver Provisions

The Act, as amended in November 1990, was designed to assure that

attainment and maintenance of the PM-10 standards, which were

promulgated in 1987 (52 FR 24634, July 1, 1987), be as expeditious as

practicable. Thus, the Act requires States to submit several revisions

of the SIP for PM-10 nonattainment areas, if necessary, to ensure

attainment of the PM-10 NAAQS as expeditiously as practicable. Among

other planning requirements, the SIP revisions must first provide for

the implementation of RACM on PM-10 sources. If RACM is not adequate to

attain the NAAQS, subsequent revisions must provide for implementation

of additional, more stringent control measures until the NAAQS are

attained.

Congress recognized that there may be areas where the NAAQS may

never be attained because of PM-10 emissions from ``nonanthropogenic

sources,''19 and that the imposition in such areas of certain

State planning requirements, as described in the previous section, may

not be justified. Therefore, under section 188(f) of the Act, Congress

provided a means for EPA to waive a specific date for attainment and

certain control and planning requirements when certain conditions are

met in the nonattainment area.

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\1\9The legislative history of the 1990 Amendments indicates

that Congress intended that the term ``nonanthropogenic'' sources of

PM-10 refer to activities where the human role in the cause of such

emissions is highly attenuated [see H.R. Rep. No. 490, 101st Cong.,

2d Sess. 265 (1990)).

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Section 188(f) provides two types of waivers. First, the

Administrator may, on a case-by-case basis, waive any requirement under

subpart 4 applicable to any serious nonattainment area where EPA

determines that anthropogenic sources of PM-10 do not contribute

significantly to the violation of the standard in the area. Second, the

Administrator may waive a specific date for attainment of the standard

where EPA determines that nonanthropogenic sources of PM-10 contribute

significantly to the violation of the standard in the area.

Section 188(f) contains two different legal tests. The first test

applies to a waiver of the serious area requirements and requires that

EPA determine that anthropogenic sources do not contribute

significantly before EPA grants such a waiver. The second test applies

to a waiver of an area's attainment date and requires that EPA

determine that nonanthropogenic sources contribute significantly before

waiving the attainment date. The first test is more stringent than the

second.

C. Application of the Waiver Provisions

Several questions must be answered before the waiver provisions can

be applied. Each of these questions is discussed in the subsections

that follow.

1. What types of sources should be considered anthropogenic and

nonanthropogenic?

The legislative history of the 1990 Amendments indicates that

Congress intended that the term ``nonanthropogenic'' sources of PM-10

refer to activities where the human role in the cause of such emissions

is highly attenuated (see H.R. Rep. No. 490 at 265). Naturally

occurring events such as wildfires, volcanic eruptions, unusually high

pollen counts, and high winds which generate dust from undisturbed land

are examples of nonanthropogenic sources that EPA believes meet the

intent of Congress.

Anthropogenic sources of PM-10 emissions are those resulting from

human activities. Some of the traditional and nontraditional

anthropogenic sources generally considered in PM-10 SIP's are

commercial, institutional, and residential fuel combustion; fossil

fuel-fired electric power plants; industrial processes; vehicular

traffic on paved and unpaved roads; construction activities;

agricultural activities; and other sources of fugitive dust which are

directly traceable to human activities and which are reasonably

foreseeable incidents of such activities.20

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\2\0``PM-10 SIP Development Guideline,'' EPA-450/2-86-001, U.S.

Environmental Protection Agency, Research Triangle Park, NC, 1987,

p. 5-5, Table 5.1.

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2. What criteria should be used in determining when

nonanthropogenic sources contribute significantly and when

anthropogenic sources do not contribute significantly to violation of

the NAAQS in the area?

The Act does not define the term ``contribute significantly'' as it

is used in section 188(f), nor does the legislative history provide any

useful guidance.21 Where a statute is silent or ambiguous with

respect to the meaning of a statutory term, a reasonable agency

interpretation of the term must be given deference by a reviewing court

(see Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc.,

467 U.S. 837, 842-845 (1984)). The EPA thus believes it has the

authority to select reasonable criteria by which to determine when

nonanthropogenic/anthropogenic sources in an area do/do not

``contribute significantly'' to levels of pollution which exceed the

NAAQS, as well as to consider for this purpose, criteria utilized in

other statutory contexts. In light of the different legal tests set

forth in section 188(f), the EPA believes that different indicators of

significance are needed to serve the statutory purpose of encouraging

protection of public health and welfare while avoiding unreasonable

control actions. The criteria which EPA believes provide a reasonable

approach to making such a determination, as well as a discussion of the

basis for selecting these criteria, are set forth below.

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\2\1It should be noted that the term ``contribute

significantly'' (or variations of that term) has been interpreted

differently throughout the Act, e.g., in the ozone/carbon monoxide

programs (see section 107(d)(4)(A)(iv) and (v)), the new source

review (NSR) program, and in specific provisions of the statute,

such as sections 110(a)(2)(D)(i)(I) and 126(a)(1)(B). An agency is

permitted, but not required, to give a similar meaning to similar

terms which appear in different parts of a statute. Thus, although

EPA is not bound to adopt the interpretation given the term

``contribute significantly'' in other parts of the statute, it is

likewise not precluded from according this use of similar language

some interpretive weight.

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Generally, where a nonattainment area's anthropogenic sources

contribute very little to violations, it is likely that controlling

those emissions to the extent feasible for the area will be

insufficient to attain the NAAQS. In such cases, it would be

unreasonable to require the area to implement more stringent and more

expensive controls on anthropogenic sources since they would contribute

little to attainment or to reducing the public's exposure to unhealthy

air quality. In similar fashion, where nonanthropogenic emission

contributions are great, even after the area has taken reasonable steps

to reduce them, at some point it may not be feasible for the area to

reduce nonanthropogenic (or anthropogenic) emissions sufficiently to

effect any real change in ambient concentrations. Consequently, it

would be unreasonable to require the area to continue to pursue control

measures that are beyond the area's practicable abilities. These

principles are discussed below in connection with each of the two

waiver tests.

In selecting an appropriate ``significance'' contribution from

anthropogenic sources (for the purposes of deciding whether serious

area requirements should be waived), EPA has elected to rely on the

test of significance that is applied under new source permitting

programs. Under the new source review (NSR) permit program, the EPA

requires State permitting programs to consider new major sources or

major modifications as causing or contributing to a violation of the

PM-10 NAAQS when the source would add, at a minimum, over 5 g/

m\3\ to the 24-hour average or over 1 g/m\3\ to the annual

average PM-10 concentrations in an area that does not or would not meet

the PM-10 NAAQS (see 40 CFR 51.165(b)). Given that the purpose of new

source permitting programs is also to protect air quality in both

attainment and nonattainment areas, EPA generally believes that the

test of significant contribution to violations under that program

should also be applicable when determining significant contributions of

anthropogenic sources under section 188(f) of the Act. It should also

be noted that, in determining ``significance'' for purposes of section

188(f), the plain terms of that provision and its underlying purpose

dictate that EPA consider the impact of the anthropogenic sources as a

whole. Consequently, where emissions from all anthropogenic sources as

a whole contribute less than or equal to 5 g/m\3\ to 24-hour

average design concentrations and less than or equal to 1 g/

m\3\ to annual mean design concentrations in a nonattainment area,

after all RACM have been implemented,22 EPA will generally regard

such contributions as insignificant for purposes of waiving

requirements applicable to serious PM-10 nonattainment areas pursuant

to section 188(f).

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\2\2Implementation of RACM (including RACT) is required in all

moderate PM-10 nonattainment areas and that requirement is not

waived under the provisions of section 188(f). Therefore, the issue

is whether anthropogenic sources still contribute significantly to

violations of the NAAQS in an area, after implementing RACM.

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Generally, if an area meeting this test has not yet been

reclassified as serious and the area would qualify under this test for

a waiver of certain serious area requirements as deemed appropriate by

EPA (see discussion below), then EPA will not require reclassification,

since that action would have no practical effect. Generally, if the

contribution of anthropogenic emissions to the 24-hour design

concentration exceeds 5 g/m\3\, or if the contribution to the

annual design concentration exceeds 1 g/m\3\, even after the

application of all RACM, then the area should be reclassified as

serious, and serious area requirements, including BACM, should be

implemented. The EPA will consider exercising its authority to waive

serious area requirements on a case-by-case basis where the

anthropogenic source contribution exceeds these levels, and it can be

persuasively demonstrated that because of unique circumstances,

anthropogenic sources do not contribute significantly to violations of

the PM-10 NAAQS in the area.

The EPA will consider nonanthropogenic sources to contribute

significantly (and hence grant an attainment date waiver) only if,

after the application of RACM to nonanthropogenic sources, their

contribution to the 24-hour average design concentration exceeds 150

g/m\3\, or their contribution to the annual mean design

concentration exceeds 50 g/m\3\. Because the basic purpose of

title I is to protect public health and welfare through attainment and

maintenance of the NAAQS, EPA believes that before it may generally

presume a serious area's nonanthropogenic emissions contribution to be

significant, that contribution should by itself prevent the area from

attaining the NAAQS after reasonable steps have been taken to reduce or

minimize their impacts. Areas which do not meet the above criteria, and

other situations for which the general presumption is rebutted, will be

reviewed on a case-by case basis (see question 4 below).

Information derived from chemical and optical analyses of ambient

filter catches, area emission inventories, and dispersion modeling to

determine maximum source impacts can be used to evaluate the impact of

anthropogenic and nonanthropogenic sources. Analysis of filters

collected with a network of monitors over a long period (1 or more

years) should reveal the portions of normal area PM-10 concentrations

attributable to background, nonanthropogenic, and anthropogenic

sources, respectively.

3. Under what conditions will the attainment date for a moderate

area be waived?

The effect of waiving the attainment date for a moderate area is to

relieve it of the serious area requirements. Therefore, special

considerations apply to the determination of whether nonanthropogenic

sources contribute significantly to violation of the PM-10 NAAQS in a

moderate area and whether such area therefore qualifies for an

attainment date waiver.

The significant disparity between the legal tests set out in

section 188(f), as discussed above, may lead to an absurd result. In

particular, if a moderate area met the less stringent attainment date

waiver test and the attainment date for the area was actually waived,

the area would never be reclassified.\23\ The result would be that a

moderate area would be effectively relieved from the serious area

requirements without having met the more stringent test that Congress

expressly required be met as a prerequisite to a waiver of such

requirements. In such an event, the more stringent test for determining

whether to waive serious area requirements would be rendered

meaningless. Moderate areas would qualify for the attainment date

waiver, be effectively relieved of all serious area requirements and

never have to meet the required test for such waiver.

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\23\If EPA waives a specific attainment date for a moderate area

consistent with its authority under section 188(f), the attainment

date for the area will be vacated. Therefore, the moderate area

would not be subject to reclassification under section 188(b)

because there simply would be no attainment date that the area

cannot practicably meet or that the area fails to meet. However,

since section 188(f) authorizes waiving only the attainment date,

the moderate area would still be subject to all the remaining

moderate area SIP requirements. Therefore, the moderate area SIP

submitted to meet the applicable requirements of subparts 1 and 4

must, among other requirements, continue to provide for

implementation of RACM.

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To avoid this absurd result and only grant a waiver of the serious

area requirements consistent with the legal standard set out in the

Act, EPA has construed section 188(f) in the following manner. A

moderate area may only qualify for an attainment date waiver if it also

qualifies for a waiver of the serious area requirements. Therefore, EPA

must determine that anthropogenic sources in the area do not contribute

significantly to the violation of the PM-10 NAAQS, and the serious area

requirements should be waived before EPA can grant an attainment date

waiver for a moderate area. If such a determination is made, then the

attainment date may be waived and the area would not be reclassified.

These special considerations would not be relevant where EPA is

determining whether to waive the attainment date for a serious area

since waiving the date in such circumstances would not as a matter of

course have the effect of relieving the area of the serious area

requirements. An area already reclassified as serious could qualify for

an attainment date waiver solely by showing that nonanthropogenic

emissions contribute significantly to the nonattainment problem.

As part of its policy, EPA will require that areas receiving

waivers be revisited periodically to reevaluate source contributions,

to ensure that source emissions growth is reasonably controlled, and to

determine whether additional controls to reduce the public's exposure

to high concentrations of PM-10 are available (see also the discussion

under question 5).

4. What happens if an area cannot meet the general criteria

described above?

If evidence in a given nonattainment area suggests that

nonanthropogenic emissions may contribute significantly to violations

but are not greater than 150 g/m3 and/or anthropogenic

source contributions are relatively small but not less than 5

g/m3, then EPA will review the situation on a case-by-

case basis taking into account relevant information such as the

relative contribution of nonanthropogenic emissions/anthropogenic

emissions and the effects of applying additional controls to both types

of sources.

For moderate areas, if preliminary data (emission inventory, filter

analysis, etc.) persuasively indicate that anthropogenic emissions may

be insignificant and that nonanthropogenic emissions may be significant

in an area, but such data are not decisive, then EPA will consider

granting a temporary or conditional waiver of the moderate area

attainment date for no more than 3 years to allow further evaluation of

the situation. Prior to granting a temporary waiver, EPA and the State

must agree on a protocol for evaluating the impacts of anthropogenic

and nonanthropogenic emissions. The protocol must include a schedule

with interim milestones by which the State will complete its analyses.

The schedule should consider the need for the area to adopt and

implement BACM so as to meet the applicable serious area attainment

date (as expeditiously as practicable and, for those areas designated

nonattainment under section 107(d)(4)(B), no later than December 31,

2001) in the event the evaluation demonstrates that nonanthropogenic

emissions do not contribute significantly to violations in the area. If

the evaluation conclusively demonstrates that nonanthropogenic

emissions are significant, then a waiver of the serious area attainment

date may be granted.

If it is shown for any moderate nonattainment area that, although

nonanthropogenic emissions may be significant, the application of

controls on anthropogenic sources would appreciably reduce PM-10

concentrations in the area, then the area would not be granted a waiver

of the moderate area attainment date, but would be reclassified as

serious. The area would then be required to implement BACM on non-de

minimis anthropogenic source categories (see discussion in section VI).

However, subsequent to such reclassification, the area may later apply

for a waiver of the serious area attainment date if it can demonstrate

that even after implementing BACM (and after considering the extended

attainment and post-attainment provisions of sections 188 and 189 of

the Act), nonanthropogenic emissions will prevent the area from

attaining the NAAQS.

5. For what period may a specific attainment date be waived?

When nonanthropogenic sources have been determined to contribute

significantly to violations in an area that has been reclassified to

serious, in accordance with the above criteria, those sources may

permanently prevent the area from attaining the standards. Therefore,

the attainment date for such areas could be waived indefinitely.24

``However, the phrase waive a specific date'' does not require that the

attainment date be waived indefinitely (see footnote 23 on the effect

of waiving the moderate area attainment date), nor does it lessen the

State's obligation to strive to expeditiously attain the NAAQS at some

time in the future through available means. While EPA does not expect

States to exhaust their resources to meet standards that may be

unattainable, it does expect them to continue efforts to minimize

exposures to unhealthy air.

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\2\4In cases where it is feasible to implement measures that

will reduce future emissions from nonanthropogenic sources (i.e.,

planting indigenous vegetation or establishing wind breaks), EPA has

the authority under section 188(e) to extend the attainment date for

a serious area for up to 5 years beyond 2001 if it is possible that

the NAAQS could be attained in the future. Such measures should be

considered by States before seeking waivers of the attainment date.

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Even though a specific attainment date and serious area

requirements may be waived indefinitely for an area where,

respectively, nonanthropogenic sources contribute significantly to

violations and anthropogenic sources do not, the State should review

the status of anthropogenic and nonanthropogenic source contributions

in the area every 3 years. Such a review would entail determining

whether nonanthropogenic sources still contribute significantly and

anthropogenic sources do not contribute significantly to violation of

the PM-10 NAAQS in the area. Since emissions from anthropogenic sources

increase with population growth and the location of new sources to the

area, the contribution of anthropogenic sources to violations can

become significant over time. Therefore, the need for reinstating a

specific attainment date and/or previously waived serious area

requirements should be reconsidered periodically.

The EPA has the authority under section 172(c)(3) to require

periodic updates of a nonattainment area's emissions inventory to

assure that the requirements of part D are met. The EPA plans to use

this authority to periodically review the waiver status of areas, as

described above. A specific attainment date and applicable requirements

should be reinstated if it is determined that nonanthropogenic sources

no longer contribute significantly or anthropogenic sources begin

contributing significantly to violations in the area.

6. What requirements applicable to serious nonattainment areas

under subpart 4 of part D should be waived?

The individual subpart 4 requirements (see section IV. above) will

be waived only after considering all relevant circumstances on a case-

by-case basis for serious areas where anthropogenic sources do not

contribute significantly and where RACM have been implemented.

Currently, the section 189(b)(3) requirement to modify the definitions

of ``major source'' and ``major stationary source'' is the only serious

area requirement that will not be waived.

D. Waiver Policy Description

Consistent with the discussion above, the EPA intends to implement

its authority to grant waivers under section 188(f) in a manner

described by the diagram presented in Figure 1. It is important to note

that this diagram is provided for illustrative purposes only and should

not be interpreted contrary to the policy as it is described in this

notice. The figure presents six decision questions. A SIP submitted for

a moderate nonattainment area seeking a waiver is expected to address

the first three questions:

1. Can the area attain the NAAQS by the applicable statutory

attainment date (December 31, 1994 for the initial nonattainment areas)

after implementing RACM (including RACT) for contributing anthropogenic

and nonanthropogenic sources?

If the moderate area SIP demonstrates that the area can attain with

RACM (including RACT) by the attainment date, then the answer to this

question is ``yes'' and the waiver provisions are not applicable.

BILLING CODE 6560-50-P

TP16AU94.002

BILLING CODE 6560-50-C

If an area cannot attain by the statutory deadline, then questions

2 and 3 on the waiver policy diagram must be addressed, and several

cases may exist.

2. Do anthropogenic sources of PM-10 as a whole contribute

significantly to violations in the area?

3. Do nonanthropogenic sources of PM-10 as a whole contribute

significantly to violations in the area?

Case #1

If anthropogenic sources no longer contribute significantly to

violations in the area after the implementation of RACM, then by

default, nonanthropogenic sources must contribute significantly.25

In this case, the moderate area attainment date may be waived. The

practical effect of waiving the attainment date for a moderate area is

to relieve it from reclassification as serious and, therefore, to

relieve it from certain serious area requirements. Therefore, a

moderate area may only qualify for an attainment date waiver if it also

qualifies for a waiver of the serious area requirements (see section

V.C., question 3). The State should reevaluate the impact of

anthropogenic sources on the area periodically to determine whether or

not they contribute significantly to violations.

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\2\5It is likely that Congress intended all areas--even those

eligible for waivers--to implement whatever measures were reasonably

available. Therefore, EPA believes the best reading of the statute

requires that the emission reductions attributable to RACM

(including RACT) should be considered before evaluating the

significance of anthropogenic contributions.

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Case #2

If anthropogenic sources still contribute significantly to

violations in the area after the implementation of RACM (i.e.,

contribute over 5 g/m3 to PM-10 concentrations), then the area

would be reclassified as serious. Consequently, the serious area

requirements discussed in section IV, above, would have to be

implemented in the area. These requirements include, among other

things, the application of BACM (including BACT) on source categories

that are still contributing significantly to violations (see the

discussion of BACM in section VI and footnote 33).

Subsequently, the area may qualify for a waiver of the serious area

attainment date if it is demonstrated that nonanthropogenic source

contributions (i.e., contributions greater than 150 g/m3)

would prevent the area from attaining the NAAQS.

Case #3

If anthropogenic sources contribute significantly to violations,

but, nonanthropogenic sources contribute less than 150 g/m3,

then waivers will be granted on a case-by-case basis as discussed above

in subsection C., question 4. The eligibility for and timing of serious

area attainment date waivers would depend upon the answers to the last

three questions on the waiver policy diagram.

4. Can the serious area attain by the statutory deadline after

implementing the serious area control strategy (i.e., BACM, (including

BACT)), for significant anthropogenic sources?

If the State can demonstrate that it is possible to attain the

NAAQS by the statutory deadline for serious areas through the

implementation of BACM, then a waiver is not appropriate. If attainment

by the deadline is not possible, then question 5 must be addressed.

5. Can the area attain with an extension of up to 5 years of the

attainment date?26

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\2\6The EPA may grant a single extension of the attainment date

for serious areas of no more than 5 years under the conditions of

section 188(e) of the Act. Guidance on demonstrating that a State

qualifies for an attainment date extension will be issued in the

future.

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To answer this question, the State must determine if an extension

of time will make it technologically and economically feasible to

implement additional control measures that will bring the area into

attainment. Again, if it is possible to attain the NAAQS, then a waiver

is not appropriate. If attainment is not possible even with the maximum

extension of the attainment date allowed under section 188(e), then

question 6 must be addressed.

6. Can the area attain at any time after the extension deadline if

emissions within the area are reduced annually by not less than 5

percent?27

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\2\7If an area fails to attain the NAAQS by the end of the

extension period, then the State must plan to achieve annual

reductions of not less than 5 percent of PM-10 and PM-10 precursor

emissions within the area, as reported in the most recent inventory

(see section 189(d)).

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To answer this question, the State must determine if the

implementation of additional control measures, annually, would

eventually bring the area into attainment. Sufficient additional

control measures would need to be implemented to achieve at least 5

percent annual reductions in the inventory of PM-10 emissions from

anthropogenic sources.

If EPA believes that it is practicable for an area, where both

anthropogenic and nonanthropogenic sources contribute to violations, to

attain the NAAQS at any time in the future, a specific attainment date

would not be waived. Rather, as discussed previously, the State would

be expected to follow the provisions in sections 188 and 189 for

attainment date extensions and continued emission reductions until the

NAAQS are attained. However, if emissions from anthropogenic sources

are reduced to the point that it is no longer technologically or

economically feasible to reduce those emissions further, and the area

still cannot attain the NAAQS, then EPA may consider waiving the

serious area attainment date and appropriate serious area requirements.

VI. Best Available Control Measures

A. Requirement for BACM

There are two circumstances, as discussed earlier, under which a

moderate PM-10 nonattainment area may be reclassified as serious.

First, an area may be reclassified whenever EPA determines that the PM-

10 NAAQS cannot practicably be attained by the statutory attainment

date.28 Such a determination may be made before the attainment

date if a review of the SIP for an area shows that RACM, including

RACT, will not practicably bring the area into attainment or if delays

in adopting, submitting, and implementing SIP requirements form a basis

for EPA to conclude that an area cannot practicably attain the NAAQS by

the statutory attainment date. The second circumstance is when the area

is reclassified by operation of law upon a determination by EPA that

the area has failed to attain the NAAQS on schedule (see section

188(b)).

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\2\8The statutory attainment date for the initial group of areas

designated nonattainment by operation of law upon enactment of the

1990 Amendments, under section 107(d)(4), is December 31, 1994.

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Section 189(b) establishes additional control requirements for PM-

10 nonattainment areas that are reclassified as serious by EPA. Under

section 189(b)(1)(B), States must submit SIP revisions which provide

for implementation of the BACM for PM-10 emissions in such areas. These

SIP revisions must be submitted to EPA within 18 months after an area

is reclassified and must assure that the measures are implemented no

later than 4 years after the area is reclassified as serious (see

section 189(b) (1) and (2)).

The EPA believes the requirement to implement BACM in serious PM-10

nonattainment areas should, in one respect, be interpreted similarly to

the comparable requirement to implement RACM in moderate PM-10

nonattainment areas. Section 172(c)(1), which applies to all

nonattainment areas, states that part D RACM shall include ``such

reductions in emissions from existing sources in the area as may be

obtained through the adoption, at a minimum, of reasonably available

control technology * * *.'' Thus, moderate PM-10 nonattainment area

RACM plans, which are submitted to meet the requirements of section

189(a)(1)(C), must include provisions ensuring the adoption of RACT

(see 57 FR 13540, column 1).

For moderate PM-10 areas reclassified as serious, the nonattainment

control requirements (i.e., RACM) are carried over and elevated to a

higher level of stringency (i.e., BACM). So, by analogy, just as RACM

includes RACT, in the same way, BACM includes BACT.29 Thus, just

as moderate PM-10 SIP revisions when implementing RACM under section

189(a)(1)(C) must provide for the adoption of RACT, similarly, PM-10

SIP revisions under section 189(b)(1)(B), implementing BACM in serious

PM-10 nonattainment areas, must include provisions ensuring the

adoption of BACT. This point was explicitly addressed in the House

Committee Report: ``Serious areas must include in their submission

provisions to require that the best available control measures for the

control of PM-10 emissions are implemented no later than 4 years after

the area is classified or reclassified as serious. Such provisions must

include the application of the best available control technology to

existing stationary sources'' (H.R. Rep. No. 490, 101st Cong., 2nd

Sess. 266-67 (1990)).

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\2\9Even without the RACM analogy, the best available

technological control measures by their plain terms are a subset of

the universe of best available control measures.

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Although section 189(b)(1)(B) requires BACM (including BACT) to be

implemented in serious PM-10 nonattainment areas, the Act does not

define either BACM or BACT for PM-10 nonattainment purposes. Where a

statute is silent or ambiguous with respect to the meaning of a

statutory term, the agency is authorized to adopt an interpretation

reasonably accommodated to the purpose of the statutory

provisions.30 In considering how to interpret the provisions

requiring BACM (including BACT) for serious PM-10 nonattainment areas,

EPA has looked at several factors: The way in which similar terms have

been historically interpreted in other sections or titles of the Act,

the ordinary grammatical usage associated with the word ``best,'' and

the overall structure and purpose of title I of the statute.

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\3\0Chevron, U.S.A., Inc. v. Natural Resources Defense Council,

Inc., 467 U.S. 837, 843-44 (1984).

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B. EPA's Historical Interpretation of Control Technology Terminology

The Act uses several terms to refer to different levels of emission

control technology required for existing or new sources: ``reasonable

(RACT),'' ``best (BACT),'' and lowest achievable emission rate (LAER).

It is helpful to consider EPA's past and current interpretation and

implementation of these various control levels in determining the

control level appropriate for BACM for serious PM-10 nonattainment

areas.

The term ``reasonably available'' was applied to control measures

and control technology required to be implemented at existing sources

in nonattainment areas by the 1977 Clean Air Act Amendments (1977

Amendments) (42 U.S.C. 7502(c)(1)). At that time, EPA defined RACT as

the lowest emission limitation that a particular source is capable of

meeting by the application of technology that is reasonably available

considering technological and economic feasibility.31 Control

measures were determined to be reasonable after considering their

energy and environmental impacts and their annualized capital and

operating costs. In EPA's view, the cost of using a control measure is

considered reasonable if those same costs are borne by other comparable

facilities. Since Congress, in the 1990 Amendments, did not modify

EPA's interpretations of the RACM and RACT in the earlier 1977

Amendments, it can be presumed to have given some endorsement to EPA's

definition of the term.

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\3\1See, for example, 44 FR 53761-53762 (September 17, 1979) and

footnote 3 of that notice. Note that EPA's emissions trading policy

statement (51 FR 43814 (December 4, 1986)) has clarified that RACT

requirements may be satisfied by achieving ``RACT equivalent''

emissions reductions in the aggregate from the full set of existing

stationary sources subject to those requirements (see also EPA's

proposed economic incentives rule, 58 FR 11110, 11123 (February 23,

1993)).

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Congress defined the term ``best available control technology'' in

section 169(3) of the 1977 Amendments for use in implementing the

requirement to prevent significant deterioration (PSD) of air quality

under part C, title I, of that Act. This definition was modified by

section 403(d) of the 1990 Amendments. The BACT is currently defined

for the PSD program as an emission limitation based on the ``maximum

degree of reduction of each pollutant * * * emitted from or which

results from any major emitting facility, which the permitting

authority, on a case-by-case basis, taking into account energy,

environmental, and economic impacts and other costs, determines is

achievable for such facility through application of production

processes and available methods, systems, and techniques * * * for

control of each such pollutant.'' Thus, BACT is to be determined for

the PSD program on a case-by-case basis taking into account the energy,

environmental, and economic impacts and other costs. Section 169(3)

also requires that BACT be at least as stringent as any corresponding

new source performance standard (NSPS) or national emission standard

for hazardous air pollutants (NESHAP).

Under the PSD program, BACT applies through preconstruction permits

issued to major new and major modified facilities in areas where the

air quality is better than the NAAQS (section 165(a)(4) of the Act, 42

U.S.C. 7475(a)(4)). In broad overview, BACT is determined by

identifying the technologically feasible control measures, from the

universe of available control techniques, which yield the maximum

degree of emission reduction, after considering the energy,

environmental and economic impacts of the technology, and other costs.

This may include consideration of the annualized capital and operating

costs for the facility. The costs of control for a major new facility

or major modification of an existing facility should be considered as a

portion of the overall costs of the new facility.

The term LAER refers to the level of control required for issuing a

preconstruction permit to major new or major modified facilities in

areas where the air quality is worse than the NAAQS (i.e.,

nonattainment areas) (section 173(a)(2) of the Act, 42 U.S.C.

7503(a)(2)). In broad terms, LAER is defined at section 171(3) of the

Act as the more stringent emission rate based on either the most

stringent State emission limit or the most stringent emission limit

achieved in practice by such class or category of source. Like BACT,

the LAER level of control must be at least as stringent as the NSPS

applicable to the source. Unlike RACT and BACT, the LAER requirement

does not consider energy or cost factors. In general, the costs of

achieving LAER in a nonattainment area must be considered as a portion

of the overall cost of investing in a major new or major modified

facility, as they are with BACT in attainment areas. The EPA believes

that it is reasonable to conclude that in selecting the term ``best''

to apply to control measures in PM-10 serious nonattainment areas,

Congress likely considered how the term has been interpreted in other

sections and titles of the Act. Several other factors (discussed below)

support such a conclusion.

C. BACM for Serious PM-10 Nonattainment Areas

A plain-English interpretation of the term ``best'' implies a

generally higher standard of performance than one that may be

considered ``reasonable.'' In addition, the structural scheme

throughout title I of the Act is to require the implementation of

increasingly stringent control measures in areas with more serious

pollution problems, while providing such areas a longer time to attain

the applicable standards. This structural scheme reflects a basic

underlying premise of title I. The premise is (1) That more stringent

control measures are needed in cases when the current control

requirements will be insufficient to bring a particular area into

attainment; and (2) that the more serious the air quality problem, the

more reasonable it is to require States to implement control measures

of greater stringency despite the greater burdens such measures are

likely to cause. The Act attempts to balance the greater burden imposed

in those areas where more stringent controls are required by affording

the State additional time to implement them.

For example, under section 188(e), EPA is given authority to

extend the attainment date for a serious PM-10 nonattainment area

beyond the specified statutory date, provided certain conditions are

met. One of those conditions is that the State must demonstrate to

EPA's satisfaction that ``the plan for that area includes the most

stringent measures that are included in the implementation plan of any

State or are achieved in practice in any State, and can feasibly be

implemented in the area.'' Thus, under this section, the Act provides

such areas an opportunity to receive additional time to attain the

NAAQS. The consequence of receiving additional time, however, is that

the State must demonstrate that its PM-10 implementation plan contains

the ``most stringent measures'' that can feasibly be implemented in the

relevant area from among those which are either included in any other

SIP or have been achieved in practice by any other State.

Similarly, the Act requires the application of control measures

that are ``reasonable'' in moderate PM-10 nonattainment areas (RACM)

and control measures that are ``best'' (BACM) whenever a moderate area

cannot ``practicably'' attain or fails to attain the NAAQS and is

therefore reclassified as serious. Accordingly, for the reasons stated

above, EPA believes it is reasonable to conclude that Congress intended

a greater level of stringency to apply in areas that are required to

implement ``best available'' controls than in those required only to

implement controls that are ``reasonably available.''

As noted earlier, an array of different control measures is

applicable under various title I NAAQS-related programs. A key factor,

among others, in determining the level of control appropriate for a

given area from among the different emission control measures and

technologies referred to throughout title I is the severity of the air

pollution problem in that area. In addition to the general

categorization of areas as ``attainment,'' ``nonattainment,'' and

``unclassifiable,'' the Act characterizes the severity of an area's air

pollution problem by classifying the area, for example, as

``marginal,'' ``moderate,'' ``serious,'' and so on. As discussed above,

the different control measures are required to be implemented as

follows: For new (or modified) sources, BACT applies in PM-10

unclassifiable and attainment areas under the PSD program, while LAER

applies in moderate and serious PM-10 nonattainment areas under the

nonattainment NSR program; for existing sources, RACM (including RACT)

applies in moderate PM-10 nonattainment areas, while BACM (including

BACT) applies in serious PM-10 nonattainment areas. In each case, the

more serious the pollution problem, the more stringent the control

standard required.

It is apparent that in requiring the application of BACM to

existing sources in serious PM-10 areas, Congress implied that these

sources should be subject to a more stringent level of control than the

application of RACM required for existing sources in moderate PM-10

nonattainment areas, but not as stringent as the application of LAER

required for new or modified sources in moderate and serious

nonattainment areas (or the degree of control required to secure an

extension under section 188(e)).

1. Definition

In view of the preceding discussion, EPA believes that, as a

starting point in interpreting BACM for PM-10 nonattainment purposes,

it is reasonable to consider the term BACT as applied in the PSD

program under section 169(3) as an analogue. Because PSD BACT and PM-10

BACM (which includes BACT) are similar terms, EPA believes it is

reasonable to accord some interpretive weight to this use of similar

language.32

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\3\2Under accepted principles of statutory interpretation,

similar terms in a statute generally suggest a similar meaning, and

an agency is permitted, but not required, to give a similar meaning

to similar terms which appear in different parts of a statute.

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Therefore, EPA's interpretation of BACM for serious PM-10

nonattainment areas will generally be similar to the definition of BACT

for the PSD program. The BACM is the maximum degree of emissions

reduction of PM-10 and PM-10 precursors from a source (except as

provided in subsection C. 3) which is determined on a case-by-case

basis, taking into account energy, environmental, and economic impacts

and other costs, to be achievable for such source through application

of production processes and available methods, systems, and techniques

for control of each such pollutant. For PM-10, BACM must be applied to

existing source categories in nonattainment areas that cannot

practicably attain (or fail to attain) within the moderate area

timeframe and are reclassified as serious.33

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\3\3The term ``source categories'' for which BACM will be

required, refers to categories of area-wide sources or large

individual stationary sources of PM-10 or PM-10 precursor emissions

that may be regulated under a specific rule, generic emission limit,

or standard of performance, or a specific control program in a SIP.

For example, the SIP may regulate emissions from unpaved roads,

construction activities, residential wood combustion, asphalt

concrete batch plants, etc., as source categories. Note that, in

some instances, an entire source category may consist of one large

individual stationary source that is regulated separately under the

SIP such as a single iron and steel manufacturing facility and the

various processes therein.

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As noted above, EPA will interpret PSD BACT and PM-10 BACM as

generally similar because, despite the similarity in terminology,

certain key differences exist between control measures applicable in

the PSD and PM-10 serious nonattainment area programs. The BACT under

the PSD program applies only in areas already meeting the NAAQS, while

PM-10 BACM applies in areas which are seriously violating the NAAQS.

This difference in policy goals, arguably, suggests that the PM-10 BACM

control standard should be more stringent than that for PSD BACT. On

the other hand, the burden of installing efficient controls during

construction of a new source or source modification is generally less

onerous than retrofitting an existing PM-10 source with similar

controls. If one compares both programs in terms of these factors, the

differing regulatory and economic burdens and the different policy

purposes tend to offset each other. Nevertheless, EPA believes that the

differences in policy goals--i.e., preventing further pollution under

the PSD program and reducing existing pollution under the PM-10

nonattainment program--counsel against adopting the interpretation and

implementation of PSD BACT in its entirety for PM-10 nonattainment

purposes. Rather, EPA considers it reasonable to use the approach

adopted in the PSD BACT program as defined in section 169(3) of the Act

as an analogue for determining appropriate PM-10 nonattainment control

measures in serious areas, while at the same time retaining the

discretion to depart from that approach on a case-by-case basis as

particular circumstances warrant.

2. Preventive Measures

The EPA considers measures that prevent PM-10 emissions over the

long term (e.g., requiring gas logs in new fireplaces) to be preferable

to those measures that will only temporarily reduce emissions (e.g.,

curtailment of wood stove use during air pollution episodes or

treatment of fugitive dust sources with water). This is because such

preventive measures are inherently more effective and involve

significantly fewer resources for surveillance, enforcement, and

administration. Moreover, increasing emphasis on prevention over

mitigation is more likely to be both economically and environmentally

beneficial over the long term.

3. De Minimis Source Categories

The BACM are required for all categories of sources in serious

areas unless the State adequately demonstrates that a particular source

category does not contribute significantly to nonattainment of the

NAAQS. While EPA regards the BACM standard applicable in PM-10 serious

areas as a more stringent control standard which calls for a greater

degree of emissions control for the source categories to which it

applies, EPA also believes that it has the authority to limit the

applicability of BACM to those source categories which ``contribute

significantly'' to violations of the NAAQS. The Act leaves unresolved

the question of whether BACM is intended to be an all-inclusive

requirement applicable to every PM-10 serious area source category. It

should be noted that in section 189(b)(1)(B), which contains the

requirement that serious area PM-10 SIP's provide for the

implementation of BACM, Congress has not used the word ``all'' in

conjunction with BACM. Congress has also not stated anywhere in the

relevant law or legislative history that BACM must be applied to all

serious area source categories. Even if the statute on its face were

interpreted to require States to impose BACM on all source categories

in serious PM-10 areas, the Agency believes, based on the decision in

Alabama Power Co. v. Costle,34 that it has the authority to exempt

from regulation those source categories in the area which contribute

only negligibly to ambient concentrations which exceed the NAAQS. The

EPA believes the court's test for invoking the de minimis exemption

authority would be satisfied in circumstances where a State

demonstrates conclusively that, because of the small contribution of

the source category's emissions to the nonattainment problem, the

imposition of additional controls, such as BACM, on a particular source

category in the area would not contribute significantly to the Act's

purpose of achieving attainment of the NAAQS ``as expeditiously as

practicable.'' The EPA will have to determine from the record that,

with respect to particular serious area PM-10 source categories which

contribute to emissions in excess of the NAAQS, requiring application

of BACM would produce an insignificant regulatory benefit.

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\3\4The inherent authority of administrative agencies to exempt

de minimis situations from a statutory command has been upheld in

contexts where an agency is invoking a de minimis exemption as ``a

tool to be used in implementing the legislative design'' on the

ground that ``the burdens of regulation yield a gain of trivial or

no value'' (Alabama Power Co. v. Costle, 636 F.2d 323, 360-61 (D.C.

Cir. 1979)).

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The EPA will, in general, rely on the criteria applied under new

source permitting programs (40 CFR 51.165(b)) to determine when a

source category contributes significantly to violations of the NAAQS in

a PM-10 serious nonattainment area. The criteria will also be applied

spatially and temporally in the same way it is under new source

permitting programs.\35\

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\35\See ``Interpretation of `Significant Contribution,'''

memorandum from Richard G. Rhoads to Alexandra Smith, December 16,

1980, OAQPS Policy and Guidance Notebook, PN 165-80-12-16-007.

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As discussed above, a moderate PM-10 nonattainment area may be

reclassified as serious based on evidence that the area cannot

practicably attain the NAAQS by the statutory attainment date or

evidence that it has failed to attain by that date. The evidence,

whether modeled or measured, will generally indicate the standard (24-

hour or annual), the day, and the location of the predicted or

monitored violation. Therefore, under this policy, a source category

(see footnote 33) will be presumed to contribute significantly to a

violation of the 24-hour NAAQS if its PM-10 impact at the location of

the expected violation would exceed 5 g/m\3\. Likewise, a

source category will be presumed to contribute significantly to a

violation of the annual NAAQS if its PM-10 impact at the time and

location of the expected violation would exceed 1 g/m\3\.

Procedures for identifying source categories that continue to

significantly affect the air quality of a serious area (even after RACM

(including RACT) are implemented) and procedures for identifying the

appropriate mix of control measures applicable to those source

categories are discussed below in subsection E.

4. BACM Analysis Independent of Attainment Analysis

The overall structure and purpose of title I of the amended Act,

the standard suggested by the word ``best,'' and the differences in the

statute between the requirements for BACM as compared to those for

RACM, lead EPA to believe that, unlike RACM, BACM are to be established

generally independent of an analysis of the attainment needs of the

serious area.

As noted earlier in this section, the overall structural scheme

throughout title I of the Act is to require the implementation of

increasingly stringent control measures in areas with more serious

pollution problems, while providing such areas additional time to

attain the applicable standards. These tougher measures are deemed

necessary in cases where it appears that less stringent controls will

be insufficient to reduce emissions in an area to the level of the

NAAQS. As described above, the fact that the Act requires the

application of control measures that are ``reasonable'' in moderate PM-

10 areas and control measures that are ``best'' whenever it is

determined that a moderate area cannot ``practicably'' attain or

actually fails to attain the NAAQS and is therefore reclassified as

serious, strongly suggests that BACM is intended to be a more stringent

standard than RACM. Thus, it is reasonable to interpret the statute as

requiring a different analysis for determining BACM from the practice

of analyzing RACM according to what is reasonable in light of the

overall attainment needs of the area. Moreover, when comparing the

terms ``reasonable'' and ``best'' as applied to control measures, the

word ``best'' strongly implies that there should be a greater emphasis

on the merits of the measure or technology alone and less flexibility

in considering other factors.

Additionally, for PM-10 areas reclassified as serious before the

moderate area attainment date, States have up to 4 years, under section

189(b)(2), in which to submit their serious area attainment

demonstration. However, under section 189(b)(2), States have only 18

months after reclassification from moderate to serious to submit their

plans requiring the use of BACM for those same areas. Thus, for such

areas, Congress provided a difference of as much as 2\1/2\ years

between the required date for submitting BACM plans and the date by

which to submit a new attainment demonstration satisfying the

requirements of section 189(b)(1)(A). This pronounced difference in

timing for the serious area submittals described above is to be

contrasted with the timing for submittal of similar provisions for

moderate areas. Under section 189(a)(2), both the RACM plans and the

attainment demonstration for moderate PM-10 areas must as a general

matter be submitted at the same time. The fact that the Act requires

BACM to be adopted and implemented by an appreciable time before the

attainment demonstration is required, for areas that are reclassified

before the moderate area attainment date, suggests that Congress

intended that BACM determinations be based more on the feasibility of

implementing the measures rather than on an analysis of the attainment

needs of the area.\36\ Therefore, the steps described below for making

a BACM determination are intended to be carried out independently from

the analysis to determine the emission reductions that would be

necessary to attain the NAAQS by the statutory deadline. If the

attainment demonstration for the area subsequently shows that BACM will

bring the area into attainment before the statutory deadline, then the

plan provides for expeditious attainment of the NAAQS. However, if the

BACM are not adequate to provide for attainment of the standards, then

the State must submit additional measures with the attainment

demonstration that will result in attainment of the standard by the

statutory deadline or apply for an extension of the attainment date by

demonstrating that the specific conditions of sections 108(e) and

189(b)(1)(A)(ii) have been met.

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\36\The EPA believes this interpretation of the Act is

reasonable, even if, as to areas which are classified in the future

as serious PM-10 nonattainment areas because the areas have failed

to attain, the date BACM plans must be submitted and the date the

serious area attainment demonstration is due should happen to

coincide. There is no rational basis for interpreting BACM

differently depending merely on when an area happens to be

reclassified.

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D. Procedures for Determining Best Available Control Measures

1. Inventory Sources of PM-10 and PM-10 Precursors

The BACM (including BACT) applicable in a nonattainment area must

be determined on a case-by-case basis since the nature and extent of a

nonattainment problem may vary within the area and from one area to

another. Nonattainment problems range from reasonably well-defined

areas of violation caused by a specific source or group of sources to

violations over relatively broad geographical areas due predominantly

to large numbers of small sources widely-distributed over the area. The

BACM are required for all source categories for which the State cannot

conclusively demonstrate that their impact is de minimis. As stated

above, the EPA will generally presume the contribution to nonattainment

of any source category to be de minimis if the source category causes a

PM-10 impact in the area of less than 5 g/m\3\ for a 24-hour

average and less than 1 g/m\3\ annual mean concentration. The

starting point for making a BACM determination would be to reevaluate

the emission inventory submitted with the moderate area SIP. Section

172(c)(3) of the Act calls for all nonattainment areas to submit

comprehensive, accurate, and current emissions inventories and provides

for such periodic revisions as may be necessary to assure that the

nonattainment planning requirements are met. If there have been any

significant changes in PM-10 sources in the area since the inventory

was first compiled (i.e., sources permanently shut down or new or

modified sources constructed) or if the inventory is not adequate to

support the more rigorous analysis required for serious area SIP

demonstrations, it should be revised. All anthropogenic sources of PM-

10 emissions and PM-10 precursors (if applicable)\37\ and

nonanthropogenic sources in a nonattainment area must be included in

the emission inventory.

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\37\Ambient filter analysis and inventory information may have

been presented in certain moderate area SIP to indicate the

insignificance of secondary particles (see 57 FR 13541-42).

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Because of its importance in identifying anthropogenic and

nonanthropogenic sources and the applicability of BACM requirements,

the breakdown of sources to consider when compiling an emissions

inventory are as follows:

a. Major point sources (i.e., sources with the potential to emit at

least 70 tons per year of PM-10 (or PM-10 precursors) as required in

sections 189(b)(3) and 189(e) of the Act).

b. Minor point source categories.

c. Area source categories such as fugitive dust from anthropogenic

sources (e.g., construction activities, paved and unpaved roads,

agricultural activities, etc.), residential wood combustion, prescribed

burning, and commercial/institutional fuel combustion.

d. Nonanthropogenic sources.

2. Evaluate Source Category Impact

The second step in determining BACM for an area is to identify

those source categories having a greater than de minimis impact on PM-

10 concentrations. The potential maximum impact of various source

categories may have been determined with receptor or dispersion

modeling performed for the attainment demonstration submitted with the

moderate area SIP. In addition, the impact of some source categories

may be apparent from analysis of ambient sampling filters from days

when the standards are exceeded. If modeling was not performed during

development of the moderate area SIP, receptor modeling, screening

modeling or, preferably, refined dispersion modeling will generally be

necessary at this time to identify key source categories.

3. Evaluate Alternative Control Techniques

In developing a fully adequate BACM SIP, the State is expected to

evaluate the technological and economic feasibility of the control

measures discussed in the BACM guidance documents\38\ and other

relevant materials for all source categories impacting the

nonattainment area except those with a de minimis impact considering

emission reductions achieved with RACM.

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\38\See ``Technical Information Document for Residential Wood

Combustion Best Available Control Measures,'' EPA-450/2-92-002,

September 1992; ``Prescribed Burning Background and Technical

Information Document for Best Available Control Measures,'' EPA-450/

2-92-003, September 1992; and, ``Fugitive Dust Background Document

and Technical Information Document for Best Available Control

Measures,'' EPA-450/2-92-004, September 1992.

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Energy and environmental impacts of the control measures and the

cost of control should be considered in determining BACM. In general,

for the reasons stated above, the test of economic and technological

feasibility will be higher for source categories in serious areas than

for source categories in moderate areas because of the greater need for

emission reductions to attain the NAAQS. As noted earlier, this

interpretation is consistent with the overall statutory scheme which

requires that as an area's air quality worsens, increasingly stringent

control measures are to be adopted in conjunction with the area

receiving more time to attain the NAAQS. Thus, measures that were not

considered reasonable to implement by the moderate area attainment date

may be BACM for serious areas because of the additional time available

for implementing them\39\ and because of the higher degree of

stringency implied by the statutory scheme and the term ``best.''

Therefore, BACM could include, though it is not limited to, expanded

use of some of the same types of control measures as those included as

RACM in the moderate area SIP.

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\39\The statutory attainment date for initial moderate PM-10

nonattainment areas reclassified as serious will be December 31,

2001. For areas designated nonattainment subsequent to enactment of

the 1990 Amendments that become serious, the attainment date will be

before the end of the tenth year beginning after the area's

designation as nonattainment (see section 188(c)).

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It does not currently appear that mobile sources, as distinct from

the surfaces on which they travel, contribute significantly to the PM-

10 air quality problem in a sufficient number of areas to warrant

issuing national guidance on best available transportation control

measures for PM-10 under section 190 of the Act. However, in those

areas where mobile sources do contribute significantly to PM-10

violations, the State must, at a minimum, address the transportation

control measures listed in section 108(f) to determine whether such

measures are achievable in the area considering energy, environmental

and economic impacts and other costs.

The technological feasibility of reducing emissions from area

sources depends on the ability to alter the characteristics that affect

emissions from the sources. Those characteristics have to do with the

size or extent of the sources, their physical characteristics and the

operating procedures. Reducing emissions of fugitive dust from

construction activities, for example, could require the most effective

combination of reducing the size of the sources (i.e., acres cleared at

one time or vehicle miles traveled on unpaved surfaces), changing the

physical characteristics (i.e., silt loading on travel surfaces or

moisture content of materials handled), and/or changing the operating

practices (i.e., lower vehicle speeds, less surface area exposed to the

wind, treating or paving travel surfaces).

The technological feasibility of applying an emission reduction

method to a particular point source should consider the source's

process and operating procedures, raw materials, physical plant layout,

energy requirements, and any collateral environmental impacts (e.g.,

water pollution and waste disposal). The process, operating procedures,

and raw materials used by a source can affect the feasibility of

implementing process changes that reduce emissions and the selection of

add-on emission control equipment. The operation and longevity of

control equipment can be significantly influenced by the raw materials

used and the process to which it is applied. The feasibility of

modifying processes or applying control equipment is also influenced by

the physical layout of the particular plant. The space available in

which to implement such changes may limit the choices and will also

affect the costs of control.

4. Evaluate Costs of Control

Economic feasibility considers the cost of reducing emissions from

a particular source category and costs incurred by similar sources that

have implemented emission reductions. As with RACT determinations and

BACT/LAER analyses in other statutory contexts, EPA believes that for

PM-10 BACM purposes, it is reasonable for similar sources to bear

similar costs of emission reduction. As such, when identifying BACM,

consideration of economic feasibility should not rely on claims

regarding the ability of a particular source to ``afford'' to reduce

emissions to the level of similar sources. Otherwise, less efficient

sources might be rewarded for their inefficiency by being allowed to

bear lower emission reduction costs. Instead, economic feasibility for

PM-10 BACM purposes should focus upon evidence that the control

technology in question has previously been implemented at other sources

in a similar source category without unreasonable economic impacts.

Where the economic feasibility of a measure (e.g., road paving)

depends on public funding, EPA will consider past funding of similar

activities as well as availability of funding sources to determine

whether a good faith effort is being made to expeditiously implement

the available control measures. In other words, if 20 miles of unpaved

roads are typically paved each year, then the BACM fugitive dust

program should include paving more than 20 miles per year of existing

roads and should offer evidence of ambitious efforts to increase

funding and increase the priority for use of existing funds.

The capital costs, annualized costs, and cost effectiveness of an

emission reduction technology should be considered in determining its

economic feasibility. The ``OAQPS Control Cost Manual, Fourth

Edition,'' EPA-450/3-90-006, January 1990, describes procedures for

determining these costs. The above costs should be determined for all

technologically-feasible emission reduction options.

E. Selection of BACM for Area Sources

Once the significant PM-10 area source categories have been

identified, the State should select area source control measures from

the candidate BACM listed in the technical information documents for

fugitive dust, residential wood combustion (RWC), prescribed burning,

or any other technical information documents issued by EPA (see

footnote 38). This guidance is based on EPA's analysis of available

control alternatives for the identified source categories. While the

guidance is intended to be comprehensive, it is by no means exhaustive.

Consequently, the State is encouraged to consider other sources of

information and is not precluded from selecting other measures and

demonstrating to the public and EPA that they constitute BACM. Further,

any control measure that a commenter indicates during the public

comment period is available for a given area should be reviewed by the

planning agency. The agency should determine whether the affected

categories of sources are significant and, if so, whether the available

measure is achievable in the area considering energy, environmental,

and economic impacts and other costs.

As stated earlier, EPA considers measures that prevent PM-10

emissions over the long term to be preferable to short-term curtailment

measures. Therefore, when selecting BACM for area sources, a State

should first consider pollution preventive measures and measures that

provide for long-term sustained progress toward attainment in

preference to quick, temporary control. For example, a State should

consider requiring the replacement, over time, of old wood stoves with

cleaner-burning wood stoves or alternative fuels. Such programs would

complement and reduce dependance on wood-burning curtailment programs

adopted as RACM for the moderate area SIP. However, EPA recognizes that

such long-term measures may entail significant lead time and that

temporary measures like wood-burning curtailments may need to be

continued in serious areas, at a minimum, to provide interim health

protection.

Once the list of available measures for an area source has been

identified, the State must evaluate the technological and economic

feasibility of implementing the controls. The State may refer to the

technical information documents for procedures to determine

feasibility.

When evaluating economic feasibility, States should not restrict

their analysis to simple acceptance/rejection decisions based on

whether full application of a measure to all sources in a particular

category is feasible. Rather, a State should consider implementing a

control measure on a more limited basis, e.g., for a percentage of the

sources in a category if it is determined that 100 percent

implementation of the measure is infeasible. This would mean, for

example, that an area should consider the feasibility of paving 75

percent of the unpaved roadways even though paving all of the roads may

be infeasible. Alternatively, the State should consider whether

measures which cannot feasibly be implemented in their entirety prior

to the statutory deadline for BACM implementation could be completed

over an extended period. In that event, BACM might itself be defined to

change over time from a more limited set of measures at the initial

implementation date to a progressively tighter or more ambitious

program at later dates.

The following example is presented to illustrate how a moderate

area program of RACM for fugitive dust control may be complemented with

additional BACM after the area is reclassified as serious. Assume that

the following control measures were adopted as RACM:

1. Reduce the speed limit on unpaved county roads to 25 miles per

hour.

2. Treat all unpaved county roads, monthly, with chemical dust

suppressants within 500 feet of their intersections with paved roads.

3. Treat 10 miles of the most heavily-traveled, unpaved county

roads with chemical dust suppressants once per month.

4. Pave 4 miles of unpaved city streets.

5. Treat unpaved parking lots in the city with chemical dust

suppressants once per month.

6. Clean anti-skid materials from 50 miles of city streets within

48 hours after snow melt begins.

The same area, after being reclassified as serious, may adopt the

following BACM examples to complement the RACM program:\40\

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\40\Adoption of these types of measures may require coordination

with other local governmental entities such as the Departments of

Agriculture, Transportation, and/or the Interior.

---------------------------------------------------------------------------

1. Pave 10 miles of the most heavily-traveled, unpaved county

roads.

2. Treat 10 miles of unpaved county roads with chemical dust

suppressants once per month.

3. Pave 25 unpaved county roads within 500 feet of their

intersections with paved roads.

4. Chemically treat or pave both shoulders of 30 miles of State

highways within the county.

5. Pave all parking lots within the city.

6. Revise the specifications for winter anti-skid materials to

require cleaner, less friable materials, and reduce the quantity used

per lane-mile.

7. Require crop rotations on highly erodible lands.

8. Retire highly erodible sections of farmland and plant indigenous

vegetation as a cover instead of leaving land fallow.

9. Plant crops and windbreaks across the prevailing wind direction

on highly erodible lands.

In summary, the State must document its selection of BACM by

showing what control measures applicable to each source category (not

shown to be de minimis) were considered. The control measures selected

should preferably be measures that will prevent PM-10 emissions rather

than temporarily reduce them. The documentation should compare the

control efficiency of technologically-feasible measures, their energy

and environmental impacts and the costs of implementation.

F. Selection of BACT for Point Sources

The reviewing authority determines BACT on a case-by-case basis. As

described above, EPA would expect the reviewing authority to select an

emissions limitation that reflects the maximum degree of emission

reduction of each pollutant subject to regulation (PM-10 and/or PM-10

precursors), taking into account energy, environmental, and economic

impacts and other costs, that it determines is achievable for such

facility.

In light of preceding discussions of BACT and its statutory bases,

it is EPA's policy that BACT be determined using the analytical

methodology established in the reviewing authority's current PSD

program to the extent that it is consistent with guidance contained in

this notice. The analytical methodology used should, at a minimum,

consider a representative range of available controls (including the

most stringent, those capable of meeting standards of performance under

40 CFR part 60 or 61, and those identified by commenters during the

public comment period). Selection of a particular control system as

BACT must be justified by a comparison of the candidate control systems

considering energy, environmental, and economic impacts, and other

costs, and be supported by the record.

In addition, if the reviewing authority determines that there is no

economically-reasonable or technologically-feasible way to accurately

measure the emissions, and hence to impose an enforceable emissions

standard, it may require the source to use design, alternative

equipment, work practice, or operational standards to reduce emissions

of the pollutant to the maximum extent feasible (see, by analogy, 40

CFR 52.21(b)(12); 40 CFR 51.166(b)(12)).

Alternative approaches to reducing emissions of particulate matter

including PM-10 are discussed in ``Control Techniques for Particulate

Emissions From Stationary Sources'' - Volume I (EPA-450/3-81/005a) and

Volume II (EPA-450/3-81-005b), September 1982. The design, operation,

and maintenance of general particulate matter control systems such as

mechanical collectors, electrostatic precipitators, fabric filters, and

wet scrubbers are discussed in Volume I. The collection efficiency of

each system is discussed as a function of particle size. Information is

also presented regarding energy and environmental considerations and

procedures for estimating costs of particulate matter control

equipment. The emission characteristics and control technologies

applicable to specific source categories are discussed in Volume II.

Secondary environmental impacts are also discussed.

The BACT/LAER Clearinghouse, the EPA Control Technology Center, and

past BACT analyses for new and modified major sources under the PSD

program may be used to assist in identifying available control options

and maximum achievable emission reductions. The EPA will continue to

evaluate the need for additional guidance and will produce additional

materials as appropriate.

VII. Contingency Measures

Section 172(c)(9) requires that SIP's provide for the

implementation of specific measures to be undertaken if the

Administrator finds that the nonattainment area has failed to make RFP

toward attainment or to attain the primary NAAQS by the applicable

statutory deadline. Following the Administrator's finding, the measures

are to ``take effect without further action by the State, or the

Administrator.'' The EPA interprets this requirement to be that no

further rulemaking actions by the State or EPA would be needed to

implement the contingency measures (see generally 57 FR 13512 and

13543-544). The EPA recognizes that certain actions, such as the

notification of sources, modification of permits, etc., would probably

be needed before a measure could be implemented effectively. However,

States must show that their contingency measures can be implemented

with minimal further action on their part and with no additional

rulemaking actions such as public hearings or legislative review. After

EPA determines that a moderate PM-10 nonattainment area has failed to

attain the PM-10 NAAQS, EPA generally expects all actions needed to

effect full implementation of the measures to occur within 60 days

after EPA notifies the State of the area's failure. The State should

ensure that the measures are fully implemented as expeditiously as

practicable after they take effect.

The purpose of contingency measures is to ensure that additional

measures beyond or in addition to the required ``core'' control

measures (i.e. RACM for moderate areas and BACM for serious areas)

immediately take effect when the area fails to make RFP or to attain

the PM-10 NAAQS in order to provide interim public health and welfare

protection. The protection is considered ``interim'' because the

statute often provides for a more formal SIP revision in order to

correct, for example, the failure of an area to attain the PM-10 NAAQS

(e.g., section 189(b)--serious area plan required upon finding of

failure of moderate area to attain the PM-10 NAAQS under 188(b)(2)--and

189(d) (plan revisions required upon failure of serious area to attain

the PM-10 NAAQS)). Thus, EPA has noted previously that contingency

measures should consist of other available control measures not

contained in the applicable core control strategy (57 FR 13543). In

designing its contingency measures, the State should also take into

consideration the potential nature and extent of any attainment

shortfall for the area. The magnitude of the effectiveness of the

measures should be calculated to achieve the appropriate percentage of

the actual emission reductions required by the SIP control strategy to

bring about attainment. The EPA has recommended that contingency

measures provide the emission reductions equivalent to 1 year's average

increment of RFP (see discussion below).

Once moderate areas are subsequently reclassified as serious, the

affected States must ensure that adequate contingency measures, as

described above, are in place for such areas. This is explicitly

required under the statute. Section 189(b)(1) requires areas

reclassified as serious to submit ``an implementation plan.'' Under

section 172(c), in turn, ``plan provisions'' required under part D must

provide for the implementation of contingency measures. Accordingly,

for those moderate areas reclassified as serious, if all or part of the

moderate area plan contingency measures become part of the required

serious area control measures (i.e., BACM), then additional contingency

measures must be submitted whether or not the previously submitted

contingency measures had already been implemented. Further, the

affected States must ensure that serious areas have adequate

contingency measures considering, among other things, new information

about the potential attainment shortfall for the newly reclassified

serious area. The States must submit contingency measures for serious

areas or otherwise demonstrate that adequate measures are in place

within 3 years of reclassification.41

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\4\1The Clean Air Act does not prescribe when States containing

serious PM-10 nonattainment areas shall submit section 172(c)(9)

contingency measures (or otherwise demonstrate that adequate

contingency measures are already in place). However, section 172(b)

of the Act directs the Administrator to establish a schedule for

submittal of the plan items in section 172(c) at the time the

Administrator designates an area as nonattainment. Such schedule is

to include a date or dates ``extending no later than 3 years from

the date of the nonattainment designation'' (see section 172(b)). By

analogy, EPA concludes it is reasonable to establish that the formal

deadline for the submittal of section 172(c)(9) contingency measures

(or a demonstration that adequate contingency measures are in place)

by States containing serious PM-10 nonattainment areas is no later

than 3 years from the date of the serious area reclassification (see

Chevron, U.S.A., Inc. v. NRDC, 467 U.S. 837, 842-45 (1984)).

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VIII. Quantitative Milestones and Reasonable Further Progress

A. General Discussion

The PM-10 nonattainment area SIP's must include quantitative

milestones which are to be achieved every 3 years until the area is

redesignated attainment and which demonstrate RFP toward attainment by

the applicable date (see section 189(c) of the amended Act). Section

171(1) of the Act defines RFP as ``such annual incremental reductions

in emissions of the relevant air pollutant as are required by this part

(part D) or may reasonably be required by the Administrator for the

purpose of ensuring attainment of the applicable national ambient air

quality standard by the applicable date.'' A discussion of these

requirements follows.

B. Reasonable Further Progress

Historically, for some pollutants, RFP has been met by showing

annual incremental emission reductions sufficient generally to maintain

at least linear progress toward attainment by the specified deadline.

Requiring linear progress reductions in emissions to maintain RFP may

be appropriate in four situations:

1. When pollutants are emitted by numerous and diverse sources.

2. Where the relationship between any individual source and the

overall air quality is not explicitly quantified.

3. Where a chemical transformation is involved.

4. Where the emission reductions necessary to attain the standard

are inventory-wide.

For example, in those areas where the nonattainment problem is

attributed to area type sources (e.g., fugitive dust, residential wood

combustion, etc.), RFP should be met by showing annual incremental

emission reductions sufficient generally to maintain linear progress

towards attainment. Total PM-10 emissions should not remain constant or

increase from 1 year to the next in such an area.

Requiring linear progress reductions in emissions to maintain RFP

is less appropriate:

1. Where there are a limited number of sources.

2. Where the relationships between individual sources and air

quality are relatively well defined.

3. Where the emission control systems utilized (e.g., at major

point sources) will result in swift and dramatic emission reductions.

For example, in those areas where the PM-10 nonattainment problem

is attributed to a few stationary sources, RFP should be met by

``adherence to an ambitious compliance schedule''42 which is

likely to periodically yield significant emission reductions. Adherence

to ``an ambitious compliance schedule'' does not necessarily mean that

it would be unreasonable to achieve annual incremental emission

reductions or generally linear progress, however.

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\4\2U.S. EPA, Office of Air Quality Planning and Standards,

``Guidance Document for Correction of Part D SIP's for Nonattainment

Areas,'' Research Triangle Park, NC, January 27, 1984, page 25.

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The SIP's for PM-10 nonattainment areas must include detailed

schedules for compliance with emission regulations in the areas and

accurately indicate the corresponding annual emission reductions to be

realized from each milestone in the schedule. In reviewing the SIP, EPA

will determine whether the annual incremental emission reductions to be

achieved are reasonable in light of the statutory objective to ensure

timely attainment of the PM-10 NAAQS. Additionally, EPA believes that

it is appropriate to require early implementation of the most cost-

effective control measures (e.g., controlling fugitive dust emissions

at the stationary source) while phasing in the more expensive control

measures, such as those involving the installation of new hardware.

Section 189(c) provides that the quantitative milestones submitted

by a State for an area also must be consistent with RFP for the area.

Thus, EPA will determine an area's compliance with RFP in conjunction

with determining its compliance with the quantitative milestone

requirement. Because RFP is an annual emission reduction requirement

and the quantitative milestones are to be achieved every 3 years, when

a State demonstrates an area's compliance with the quantitative

milestone requirement, it should also demonstrate that RFP has been

achieved during each of the relevant 3 years. Thus, the discussion of

quantitative milestones below refers to the ``RFP/milestone'' submittal

dates, achievement dates and demonstration (or reporting) requirements.

C. Quantitative Milestones

1. Nature of Quantitative Milestones

As mentioned above, PM-10 nonattainment SIP's are to contain

quantitative milestones (see section 189(c)). These quantitative

milestones should consist of elements which allow progress to be

quantified or measured. Specifically, States should identify and submit

quantitative milestones providing for the amount of emission reductions

adequate to achieve the NAAQS by the applicable attainment date. The

following are examples of measures which support and demonstrate how

the overall quantitative milestones identified for an area may be met:

a. Percent implementation of various control strategies (e.g., pave

50 percent of culpable streets, replace 75 percent of residential wood

heaters with natural gas heating units).

b. Percent compliance with implemented control measures.

c. Adherence to a compliance schedule.

2. RFP/Milestone Due Dates

As mentioned above, PM-10 nonattainment SIP's are to contain

quantitative milestones which are to be achieved every 3 years until

the area is redesignated attainment. There is a gap in the law in that

the text of section 189(c) does not articulate the starting point for

counting the 3-year period. The EPA believes it is reasonable to begin

counting the 3-year milestone deadline from the due date (and not the

submittal date) for the applicable moderate area implementation plan

revision (see section III.C.1.(f) of the General Preamble (57 FR 13539)

for an explanation of why EPA believes it is appropriate to begin

counting the 3-year milestone deadline from the SIP due date).

The first ``RFP/milestone'' achievement date for those areas

initially designated as nonattainment for PM-10 by operation of law

when the Act was amended will be the moderate area attainment date of

December 31, 1994, as stated in section III.C.1.f. of the General

Preamble (57 FR 13539). The RFP/milestone achievement date would

normally be November 15, 1994, 3 years after the SIP due date of

November 15, 1991. The achievement date was delayed 46 days, however,

because the de minimis timing differential between the attainment date

and the literal first milestone date made it administratively

impracticable and of trivial value to require separate milestones and

attainment demonstrations for these areas. Thus, for these initial

areas that demonstrate timely attainment, EPA's policy is to deem the

emission reductions progress made between the SIP submittal due date

and the attainment date as sufficient to satisfy the first milestone

requirement (57 FR 13539).

Thus the initial RFP/milestone will be met by showing that emission

reductions scheduled to be made between the SIP due date and the

attainment date for these moderate areas were actually achieved. Most

of the emission reductions will result from implementation of RACM

(including RACT) adopted as part of the moderate area SIP. The Act

requires that RACM be implemented by December 10, 1993 in the initial

PM-10 nonattainment areas (see section 189(a)).

Subsequent RFP/milestones for these initial PM-10 nonattainment

areas that are reclassified as serious will be due every 3 years after

the original due date for the moderate area SIP.43 Therefore, the

second RFP/milestone for the initial nonattainment areas that are

reclassified as serious must be achieved by November 15, 1997. The

third RFP/milestone achievement date will be November 15, 2000, etc.

These RFP/milestones should be addressed by quantifying and comparing

the annual incremental emission reductions which result from

implementation of BACM/BACT (required within 4 years after the area is

reclassified as serious) and from additional measures included in the

final serious area SIP to those reductions which were identified in the

SIP as quantitative milestones necessary to achieve the NAAQS by the

applicable attainment date. The annual incremental emission reductions

must be sufficient to assure attainment as expeditiously as practicable

but not later than December 31, 2001. In some cases it may also be

appropriate to require that the annual incremental emission reductions

maintain at least linear progress toward attainment, as discussed

earlier.

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\4\3The plain terms of section 189(c) require that milestones be

achieved ``every 3 years until the area is redesignated attainment''

and, therefore, do not contemplate any breaks in the milestones due

to an area's reclassification. Further, reclassifying an area to

serious does not obviate the State from controls and emission

reductions required in the moderate area implementation plan (see

section 189(b)(1)). A continuous series of control measures must be

implemented in PM-10 nonattainment areas beginning with RACM

(including RACT) and followed by contingency measures which are to

be implemented if the moderate area fails to attain. Next, BACM

(including BACT) must be implemented within 4 years after the area

is reclassified as serious. Subsequently, it may be necessary to

implement additional control measures beyond BACM/BACT to attain the

NAAQS. Therefore, the structure of the Act requires a series of

measures which can provide for RFP/milestones.

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3. RFP/Milestone Report

The State must demonstrate to EPA, within 90 days after the

milestone achievement date, that the SIP measures are being implemented

and the RFP/quantitative milestones have been met (see section

189(c)(2)). The RFP/milestone report must be submitted from the

Governor or Governor's designee to the Regional Administrator of the

respective EPA Regional Office which serves the State where the

affected area is located.

The RFP/milestone report must contain technical support sufficient

to document completion statistics for appropriate milestones. For

example, the demonstration should graphically display RFP over the

course of the relevant 3 years and indicate how the emission reductions

achieved to date compare to those required or scheduled to meet RFP and

the required milestones. The calculations (and any assumptions made)

necessary to determine the emission reductions to date should also be

submitted. The demonstration should also contain an evaluation of

whether the PM-10 NAAQS will be attained by the projected attainment

date in the SIP, i.e., answer the question ``Are the emission

reductions to date sufficient to ensure timely attainment?''

Within 90 days of its receipt, EPA must determine whether or not

the State's demonstration is adequate and meets all the requirements

discussed above. The EPA will notify the State of its determination by

sending a letter to the appropriate Governor or Governor's designee.

4. Failure to Submit RFP/Milestone Report or Meet RFP/Milestones

If a State fails to submit the RFP/milestone report within the

required timeframes or if EPA determines that the State has not met any

applicable RFP/milestone, EPA shall require the State, within 9 months

after such failure or determination, to submit a plan revision that

assures that the State will achieve the next milestone (or attain the

PM-10 NAAQS, if there is no next milestone) by the applicable date (see

section 189(c)(3)). For example, with respect to RFP, if the required

annual emission reductions are not achieved for the relevant years

according to the RFP schedule and the implementing milestone

requirement, EPA will require the State to submit a SIP revision so

that these deviations can be corrected and attainment assured by the

applicable date. This would also necessitate implementation of

appropriate contingency measures pursuant to section 172(c)(9).

Note also that failure to meet RFP, if not expeditiously corrected,

could also result in the application of sanctions as described in

sections 110(m) and 179(b) of the amended Act (pursuant to a finding

under section 179(a)(4)).

IX. Other Requirements

A. Executive Order 12866

Under Executive Order 12866 (E.O. 12866) (58 FR 51,735 (October 4,

1993)), the Agency must determine whether the regulatory action is

``significant'' and therefore subject to the Office of Management and

Budget (OMB) review and the requirements of E.O. 12866. The E.O. 12866

defines ``significant regulatory action'' as one that is likely to

result in a rule that may:

1. Have an annual effect on the economy of $100 million or more or

adversely affect in a material way the economy, a sector of the

economy, productivity, competition, jobs, the environment, public

health or safety, or state, local, or tribal government or communities;

2. create a serious inconsistency or otherwise interfere with an

action taken or planned by another agency;

3. materially alter the budgetary impact of entitlements, grants,

user fees, or loan programs or the rights and obligations of recipients

thereof; or

4. raise novel legal or policy issues arising out of legal

mandates, the President's priorities, or the principles set forth in

the Executive Order.

Pursuant to the terms of E.O. 12866, OMB has notified EPA that this

action is a ``significant regulatory action'' within the meaning of the

Executive Order. For this reason, this action was submitted to OMB for

review. Changes made in response to OMB suggestions or recommendations

will be documented in the public record.

B. Regulatory Flexibility Act

Whenever the Agency is required by section 553 of the

Administrative Procedure Act (APA) or any other law to publish general

notice of proposed rulemaking for any proposed rule, the Agency shall

propose and make available for public comment an initial regulatory

flexibility analysis. The regulatory flexibility requirements do not

apply for this PM-10 serious area addendum to the General Preamble

because it is not a regulatory action in the context of the APA or the

Regulatory Flexibility Act.

Dated: July 29, 1994.

Carol M. Browner,

Administrator.

[FR Doc. 94-19884 Filed 8-15-94; 8:45 am]

BILLING CODE 6560-50-P