1/25/95

MEMORANDUM

SUBJECT: Options for Limiting the Potential to Emit (PTE) of a

Stationary Source Under Section 112 and Title V of the

Clean Air Act (Act)

FROM: John S. Seitz, Director

Office of Air Quality Planning and Standards (MD-10)

Robert I. Van Heuvelen, Director

Office of Regulatory Enforcement (2241)

TO: Director, Air, Pesticides and Toxics 

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation and Toxics Division,

Region III

Director, Air and Radiation Division,

Region V

Director, Air, Pesticides and Toxics Division,

Region VI

Director, Air and Toxics Division,

Regions VII, VIII, IX, and X

Many stationary source requirements of the Act apply only to

"major" sources. Major sources are those sources whose emissions

of air pollutants exceed threshold emissions levels specified in

the Act. For instance, section 112 requirements such as MACT and 

section 112(g) and title V operating permit requirements largely

apply only to sources with emissions that exceed specified levels

and are thus major. To determine whether a source is major, the

Act focuses not only on a source's actual emissions, but also on

its potential emissions. Thus, a source that has maintained

actual emissions at levels below the major source threshold could

still be subject to major source requirements if it has the

potential to emit major amounts of air pollutants. However, in

situations where unrestricted operation of a source would result

in a potential to emit above major-source levels, such sources

may legally avoid program requirements by taking federally-
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enforceable permit conditions which limit emissions to levels

below the applicable major source threshold. Federallyenforceable permit conditions, if violated, are subject to

enforcement by the Environmental Protection Agency (EPA) or by

citizens in addition to the State or Local agency.

As the deadlines for complying with MACT standards and 

title V operating permits approach, industry and State and local

air pollution agencies have become increasingly focused on the

need to adopt and implement federally-enforceable mechanisms to

limit emissions from sources that desire to limit potential

emissions to below major source levels. In fact, there are

numerous options available which can be tailored by the States to

provide such sources with simple and effective ways to qualify as

minor sources. Because there appears to be some confusion and

questions regarding how potential to emit limits may be

established, EPA has decided to: (1) outline the available

approaches to establishing potential to emit limitations, 

(2) describe developments related to the implementation of these

various approaches, and (3) implement a transition policy that

will allow certain sources to be treated as minor for a period of

time sufficient for these sources to obtain a federallyenforceable limit.

Federal enforceability is an essential element of

establishing limitations on a source's potential to emit. 

Federal enforceability ensures the conditions placed on emissions

to limit a source's potential to emit are enforceable by EPA and

citizens as a legal and practical matter, thereby providing the

public with credible assurances that otherwise major sources are

not avoiding applicable requirements of the Act. In order to

ensure compliance with the Act, any approaches developed to allow

sources to avoid the major source requirements must be supported

by the Federal authorities granted to citizens and EPA. In

addition, Federal enforceability provides source owners and

operators with assurances that limitations they have obtained

from a State or local agency will be recognized by EPA. 

The concept of federal enforceability incorporates two

separate fundamental elements that must be present in all

limitations on a source's potential to emit. First, EPA must

have a direct right to enforce restrictions and limitations

imposed on a source to limit its exposure to Act programs. This

requirement is based both on EPA's general interest in having the

power to enforce "all relevant features of SIP's that are

necessary for attainment and maintenance of NAAQS and PSD

increments" (see 54 FR 27275, citing 48 FR 38748, August 25,

1983) as well as the specific goal of using national enforcement

to ensure that the requirements of the Act are uniformly
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implemented throughout the nation (see 54 FR 27277). Second,

limitations must be enforceable as a practical matter.

It is important to recognize that there are shared

responsibilities on the part of EPA, State, and local agencies,

and on source owners to create and implement approaches to

creating acceptable limitations on potential emissions. The lead

responsibility for developing limitations on potential emissions

rests primarily with source owners and State and local agencies. 

At the same time, EPA must work together with interested parties,

including industry and States to ensure that clear guidance is

established and that timely Federal input, including Federal

approval actions, is provided where appropriate. The guidance in

this memorandum is aimed towards continuing and improving this

partnership. 

Available Approaches for Creating Federally-enforceable

Limitations on the Potential to Emit

There is no single "one size fits all" mechanism that would

be appropriate for creating federally-enforceable limitations on

potential emissions for all sources in all situations. The

spectrum of available mechanisms should, however, ensure that

State and local agencies can create federally-enforceable

limitations without undue administrative burden to sources or the

agency. With this in mind, EPA views the following types of

programs, if submitted to and approved by EPA, as available to

agencies seeking to establish federally-enforceable potential to

emit limits:1

1. Federally-enforceable State operating permit programs

(FESOPs) (non-title V). For complex sources with numerous and

varying emission points, case-by-case permitting is generally

needed for the establishment of limitations on the source's

potential to emit. Such case-by-case permitting is often

accomplished through a non-title V federally-enforceable State

operating permit program. This type of permit program, and its

basic elements, are described in guidance published in the

Federal Register on June 28, 1989 (54 FR 27274). In short, the

program must: (a) be approved into the SIP, (b) impose legal

obligations to conform to the permit limitations, (c) provide for

limits that are enforceable as a practical matter, (d) be issued

in a process that provides for review and an opportunity for

1This is not an exhaustive list of considerations affecting

potential to emit. Other federally-enforceable limits can be

used, for example, source-specific SIP revisions. For brevity,

we have included those which have the widest applicability.
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comment by the public and by EPA, and (e) ensure that there is no

relaxation of otherwise applicable Federal requirements. The EPA

believes that these type of programs can be used for both

criteria pollutants and hazardous air pollutants, as described in

the memorandum, "Approaches to Creating Federally-Enforceable

Emissions Limits," November 3, 1993. This memorandum (referred

to below as the November 1993 memorandum) is included for your

information as Attachment 1. There are a number of important

clarifications with respect to hazardous air pollutants

subsequent to the November 1993 memorandum which are discussed

below (see section entitled "Limitations on Hazardous Air

Pollutants"). 

2. Limitations established by rules. For less complex

plant sites, and for source categories involving relatively few

operations that are relatively similar in nature, case-by-case

permitting may not be the most administratively efficient

approach to establishing federally-enforceable restrictions. One

approach that has been used is to establish a general rule which

creates federally-enforceable restrictions at one time for many

sources (these rules have been referred to as "exclusionary"

rules and by some permitting agencies as "prohibitory" rules). A

specific suggested approach for volatile organic compounds (VOC)

limits by rule was described in EPA's memorandum dated October

15, 1993 entitled "Guidance for State Rules for Optional

Federally-Enforceable Emissions Limits Based Upon Volatile

Organic Compound (VOC) Use." An example of such an exclusionary

rule is a model rule developed for use in California. (The

California model rule is attached, along with a discussion of its

applicability to other situations--see Attachment 2). 

Exclusionary rules are included in a State's SIP and generally

become effective upon approval by EPA. 

3. General permits. A concept similar to the exclusionary

rule is the establishment of a general permit for a given source

type. A general permit is a single permit that establishes terms

and conditions that must be complied with by all sources subject

to that permit. The establishment of a general permit provides

for conditions limiting potential to emit in a one-time

permitting process, and thus avoids the need to issue separate

permits for each source within the covered source type or

category. Although this concept is generally thought of as an

element of a title V permit program, there is no reason that a

State or local agency could not submit a general permit program

as a SIP submittal aimed at creating potential to emit limits for

groups of sources. Additionally, general permits can be issued

under the auspices of a SIP-approved FESOP. The advantage of a

general permit, when compared to an exclusionary rule, is that

upon approval by EPA of the State's permit program, a 
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general permit could be written for one or more additional source

types without triggering the need for the formal SIP revision

process. 

4. Construction permits. Another type of case-by-case

permit is a construction permit. These permits generally cover

new and modified sources, and States have developed such permit

programs as an element of their SIP's. As described in the

November 1993 memorandum, these State major and minor new source

review (NSR) construction permits can provide for federallyenforceable limitations on a source's potential to emit. Further

discussion of the use of minor source NSR programs is contained

in EPA's letter to Jason Grumet, NESCAUM, dated November 2, 1994,

which is contained in Attachment 3. As noted in this letter, the

usefulness of minor NSR programs for the creation of potential to

emit limitations can vary from State to State, and is somewhat

dependent on the scope of a State's program. 

5. Title V permits. Operating permits issued under the

Federal title V operating permits program can, in some cases,

provide a convenient and readily available mechanism to create

federally-enforceable limits. Although the applicability date

for part 70 permit programs is generally the driving force for

most of the current concerns with respect to potential to emit,

there are other programs, such as the section 112 air toxics

program, for which title V permits may themselves be a useful

mechanism for creating potential to emit limits. For example,

many sources will be considered to be major by virtue of

combustion emissions of nitrogen oxides or sulfur dioxide, and

will be required to obtain part 70 permits. Such permits could

be used to establish federally-enforceable limitations that could

ensure that the source is not considered a major source of

hazardous air pollutants.

Practicable Enforceability

If limitations--whether imposed by SIP rules or through

individual or general permits--are incomplete or vague or

unsupported by appropriate compliance records, enforcement by the

States, citizens and EPA would not be effective. Consequently,

in all cases, limitations and restrictions must be of sufficient

quality and quantity to ensure accountability (see 54 FR 27283).

The EPA has issued several guidance documents explaining the

requirements of practicable enforceability (e.g., "Guidance on

Limiting Potential to Emit in New Source Permitting," June 13,

1989; memorandum from John Rasnic entitled "Policy Determination

on Limiting Potential to Emit for Koch Refining Company's Clean

Fuels Project," March 13, 1992). In general, practicable
6

enforceability for a source-specific permit means that the

permit's provisions must specify: (1) A technically-accurate

limitation and the portions of the source subject to the 

limitation; (2) the time period for the limitation (hourly,

daily, monthly, and annual limits such as rolling annual limits); 

and (3) the method to determine compliance including appropriate

monitoring, recordkeeping, and reporting. For rules and general

permits that apply to categories of sources, practicable

enforceability additionally requires that the provisions:

(1) identify the types or categories of sources that are covered

by the rule; (2) where coverage is optional, provide for notice

to the permitting authority of the source's election to be

covered by the rule; and (3) specify the enforcement consequences

relevant to the rule. More specific guidance on these

enforceability principles as they apply to rules and general

permits is provided in Attachment 4.

Limitations on Hazardous Air Pollutants (HAP)

There are a number of important points to recognize with

respect to the ability of existing State and local programs to

create limitations for the 189 HAP listed in (or pursuant to)

section 112(b) of the Act, consistent with the definitions of

"potential to emit" and "federally-enforceable" in 40 CFR 63.2

(promulgated March 16, 1994, 59 FR 12408 in the part 63 General

Provisions). The EPA believes that most State and local programs

should have broad capabilities to handle the great majority of

situations for which a potential to emit limitation on HAP is

needed. 

First, it is useful to note that the definition of potential

to emit for the Federal air toxics program (see the subpart A

"general provisions," section 63.2) considers, for purposes of

controlling HAP emissions, federally-enforceable limitations on

criteria pollutant emissions if "the effect such limitations

would have on "[hazardous air pollutant] . . . emissions" is

federally-enforceable (emphasis added). There are many examples

of such criteria pollutant emission limits that are present in

federally-enforceable State and local permits and rules. 

Examples would include a limitation constraining an operation to

one (time limit specified) shift per day or limitations that

effectively limit operations to 2000 hours per year. Other

examples would include limitations on the amount of material

used, for example a permit limitation constraining an operation

to using no more than 100 gallons of paint per month. 

Additionally, federally-enforceable permit terms that, for

example, required an incinerator to be operated and maintained at

no less than 1600 degrees would have an obvious "effect" on the

HAP present in the inlet stream. 
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Another federally-enforceable way criteria pollutant

limitations affect HAP can be described as a "nested" HAP limit

within a permit containing conditions limiting criteria

pollutants. For example, the particular VOC's within a given

operation may include toluene and xylene, which are also HAP. If

the VOC-limiting permit has established limitations on the amount

of toluene and xylene used as the means to reduce VOC, those

limitations would have an obvious "effect" on HAP as well. 

In cases as described above, the "effect" of criteria

pollutant limits will be straightforward. In other cases,

information may be needed on the nature of the HAP stream

present. For example, a limit on VOC that ensured total VOC's of

20 tons per year may not ensure that each HAP present is less

than 10 tons per year without further investigation. While the

EPA intends to develop further technical guidance on situations

for which additional permit terms and conditions may be needed to

ensure that the "effect" is enforceable as a practical matter, 

the EPA intends to rely on State and local agencies to employ

care in drafting enforceable requirements which recognize obvious

environmental and health concerns. 

There are, of course, a few important pollutants which are

HAP but are not criteria pollutants. Example of these would

include methylene chloride and other pollutants which are

considered nonreactive and therefore exempt from coverage as

VOC's. Especially in cases where such pollutants are the only

pollutants present, criteria pollutant emission limitations may

not be sufficient to limit HAP. For such cases, the State or

local agency will need to seek program approval under section

112(l) of the Act.

Section 112(l) provides a clear mechanism for approval of

State and local air toxics programs for purposes of establishing

HAP-specific PTE limits. The EPA intends, where appropriate,

that in approving permitting programs into the SIP, to add

appropriate language citing approval pursuant to section 112(l)

as well. An example illustrating section 112(l) approval is the

approval of the State of Ohio's program for limiting potential to

emit (see 59 FR 53587, October 25, 1994). In this notice, EPA

granted approval under section 112(l) for hazardous air

pollutants aspects of a State program for limiting potential to

emit. Such language can be added to any federally-enforceable

State operating permit program, exclusionary rule, or NSR program

update SIP approval notice so long as the State or local program

has the authority to regulate HAP and meets other section 112(l)

approval criteria. Transition issues related to such 

section 112(l) approvals are discussed below. 
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Determination of Maximum Capacity

While EPA and States have been calculating potential to emit

for a number of years, EPA believes that it is important at this

time to provide some clarification on what is meant in the

definition of potential to emit by the "maximum capacity of a

stationary source to emit under its physical and operational

design." Clearly, there are sources for which inherent physical

limitations for the operation restrict the potential emissions of

individual emission units. Where such inherent limitations can

be documented by a source and confirmed by the permitting agency,

EPA believes that States have the authority to make such

judgements and factor them into estimates of a stationary

source's potential to emit.

The EPA believes that the most straightforward examples of

such inherent limitations is for single-emission unit type

operations. For example, EPA does not believe that the "maximum

capacity" language requires that owner of a paint spray booth at

a small auto body shop must assume that (even if the source could

be in operation year-round) spray equipment is operated 8760

hours per year in cases where there are inherent physical

limitations on the number of cars that can be painted within any

given period of time. For larger sources involving multiple

emissions units and complex operations, EPA believes it can be

more problematic to identify the inherent limitations that may

exist.

The EPA intends, within its resource constraints, to issue

technical assistance in this area by providing information on the

type of operational limits that may be considered acceptable to

limit the potential to emit for certain individual small source

categories.

Transition Guidance for Section 112 and Title V Applicability

Most, if not all, States have recognized the need to develop

options for limiting the potential emissions of sources and are

moving forward with one or more of the strategies described in

the preceding sections in conjunction with the submission and

implementation of their part 70 permit programs. However, EPA is

aware of the concern of States and sources that title V or

section 112 implementation will move ahead of the development and

implementation of these options, leaving sources with actual

emissions clearly below the major source thresholds potentially

subject to part 70 and other major source requirements. Gaps

could theoretically occur during the time period it takes for a

State program to be designed and administratively adopted by the

State, approved into the SIP by EPA, and implemented as needed to
9

cover individual sources. 

The EPA is committed to aiding all States in developing and

implementing adequate, streamlined, and cost-effective vehicles

for creating federally-enforceable limits on a source's potential

emissions by the time that section 112 or title V requirements

become effective. To help bridge any gaps, EPA will expedite its

reviews of State exclusionary rules and operating permit rules

by, among other things, coordinating the approval of these rules

with the approval of the State's part 70 program and by using

expeditious approval approaches such as "direct final" Federal

Register notices to ensure that approval of these programs does

not lag behind approval of the part 70 program.

In addition, in such approval notices EPA will affirm any

limits established under the State's program since its adoption

by the State but prior to Federal approval if such limits were

established in accordance with the procedures and requirements of

the approved program. An example of language affirming such

limits was recently used in approving an Illinois SIP revision

(see 57 FR 59931, included as Attachment 5).

The EPA remains concerned that even with expedited approvals

and other strategies, sources may face gaps in the ability to

acquire federally-enforceable potential to emit limits due to

delays in State adoption or EPA approval of programs or in their

implementation. In order to ensure that such gaps do not create

adverse consequences for States or for sources, EPA is announcing

a transition policy for a period up to two years from the date of

this memorandum. The EPA intends to make this transition policy

available at the discretion of the State or local agency to the

extent there are sources which the State believes can benefit

from such a transition policy. The transition period will extend

from now until the gaps in program implementation are filled, but

no later than January 1997. Today's guidance, which EPA intends

to codify through a notice and comment rulemaking, provides

States discretion to use the following options for satisfying

potential to emit requirements during this transition period.

1. Sources maintaining emissions below 50 percent of all

applicable major source requirements. For sources that typically

and consistently maintain emissions significantly below major

source levels, relatively few benefits would be gained by making

such sources subject to major source requirements under the Act. 

For this reason, many States are developing exclusionary rules

and general permits to create simple, streamlined means to ensure

that these sources are not considered major sources. To ease the

burden on States' implementation of title V, and to ensure that

delays in EPA's approval of these types of programs will not
10

cause an administrative burden on the States, EPA is providing a

2-year transition period for sources that maintain their actual

emissions, for every consecutive 12-month period (beginning with

the 12 months immediately preceding the date of this memorandum),

at levels that do not exceed 50 percent of any and all of the

major stationary source thresholds applicable to that source. A

source that exceeds the 50 percent threshold, without complying

with major source requirements of the Act (or without otherwise

limiting its potential to emit), could be subject to enforcement. 

For this 2-year period, such sources would not be treated as

major sources and would not be required to obtain a permit that

limits their potential to emit. To qualify under this transition

policy, sources must maintain adequate records on site to

demonstrate that emissions are maintained below these thresholds

for the entire as major sources and would not be required to

obtain a permit that limits their potential to emit that would be

considered to be adequate during this transition period. 

Consistent with the California approach, EPA believes it is

appropriate for the amount of recordkeeping to vary according to

the level of emissions (see paragraphs 1.2 and 4.2 of the

attached rule). 

2. Larger sources with State limits. For the 2-year

transition period, restrictions contained in State permits issued

to sources above the 50 percent threshold would be treated by EPA

as acceptable limits on potential to emit, provided: (a) the

permit is enforceable as a practical matter; (b) the source owner

submits a written certification to EPA that it will comply with

the limits as a restriction on its potential to emit; and (c) the

source owner, in the certification, accepts Federal and citizen

enforcement of the limits (this is appropriate given that the

limits are being taken to avoid otherwise applicable Federal

requirements). Such limits will be valid for purposes of

limiting potential to emit from the date the certification is

received by EPA until the end of the transition period. States

interested in making use of this portion of the transition policy

should work with their Regional Office to develop an appropriate

certification process.

3. Limits for noncriteria HAP. For noncriteria HAP for

which no existing federally-approved program is available for the

creation of federally-enforceable limits, the 2-year transition

period provides for sufficient time to gain approval pursuant to

section 112(l). For the 2-year transition period, State

restrictions on such noncriteria pollutants issued to sources

with emissions above the 50 percent threshold would be treated by

EPA as limiting a source's potential to emit, provided that: 

(a) the restrictions are enforceable as a practical matter; 

(b) the source owner submits a written certification to EPA that
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it will comply with the limits as a restriction on its potential

to emit; and (c) the source owner, in the certification, accepts

Federal and citizen enforcement of the limits. Such limits will

be valid for purposes of limiting potential to emit from the date

the certification is received by EPA until the end of the

transition period.

The Regional Offices should send this memorandum, including

the attachments, to States within their jurisdiction. Questions

concerning specific issues and cases should be directed to the

appropriate Regional Office. Regional Office staff may contact

Timothy Smith of the Integrated Implementation Group at 

919-541-4718, or Clara Poffenberger with the Air Enforcement

Division at 202-564-8709.

Attachments

cc: Air Branch Chief, Region I-X

Regional Counsels 
Attachment 1

November 3, 1993 memorandum

November 3, 1993

MEMORANDUM

SUBJECT: Approaches to Creating Federally-Enforceable

Emissions Limits

FROM: John S. Seitz, Director

Office of Air Quality Planning and Standards (MD-10)

TO: Director, Air, Pesticides and Toxics 

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation and Toxics Division,

Region III

Director, Air and Radiation Division,

Region V

Director, Air, Pesticides and Toxics Division,

Region VI

Director, Air and Toxics Division, 

Regions VII, VIII, IX, and X

The new operating permits program under title V of the Clean

Air Act (Act), combined with the additional and lower thresholds

for "major" sources also provided by the 1990 Amendments to the

Act, has led to greatly increased interest by State and local air

pollution control agencies, as well as sources, in obtaining

federally-enforceable limits on source potential to emit air

pollutants. Such limits entitle sources to be considered "minor"

for the purposes of title V permitting and various other

requirements of the Act. Numerous parties have identified this

as a high priority concern potentially involving thousands of

sources in each of the larger States.

The issue of creating federally-enforceable emissions limits

has broad implications throughout air programs. Although many of

the issues mentioned above have arisen in the context of the

title V permits program, the same issues exist for other

programs, including those under section 112 of the Act. As

discussed below, traditional approaches to creating federallyenforceable emissions limits may be unnecessarily burdensome and

time-consuming for certain types and sizes of sources. In
addition, they have been of limited usefulness with respect to

creating such limits for emissions of hazardous air pollutants

(HAP's). 

The purpose of this memorandum is to respond to these needs

by announcing the availability of two further approaches to

creating federally-enforceable emissions limits: the extension

of existing criteria pollutant program mechanisms for HAP program

purposes, and the creation of certain classes of standardized

emissions limits by rule. We believe that these options are

responsive to emerging air program implementation issues and

provide a reasonable balance between the need for administrative

streamlining and the need for emissions limits that are

technically sound and enforceable.

Background

Various regulatory options already exist for the creation of

federally-enforceable limits on potential to emit. These were

summarized in a September 18, 1992 memorandum from John Calcagni,

Director, Air Quality Management Division. That memorandum

identified the five regulatory mechanisms generally seen as

available. These are: State major and minor new source review

(NSR) permits [if the NSR program has been approved into the

State implementation plan (SIP) and meets certain procedural

requirements]; operating permits based on programs approved into

the SIP pursuant to the criteria in the June 28, 1989 Federal

Register (54 FR 27274); and title V permits (including general

permits). Also available are SIP limits for individual sources

and limits for HAP's created through a State program approved

pursuant to section 112(l) of the Act.

Regional Office and State air program officials realize that

these five options are generally workable, but feel that the

programs emerging from the 1990 Amendments present certain

further needs that are not well met. They note that NSR is not

always available, title V permitting can be more rigorous than

appropriate for those sources that are in fact quite small, and

that general permits have limitations in their usefulness. The

use of State operating permits approved into the SIP pursuant to

the June 28, 1989 Federal Register is generally considered to be

a promising option for some of these transactions; however, these

programs do not regulate toxics directly.

State Operating Permits for Both Criteria Pollutants

and HAP's

As indicated above, State operating permits issued by

programs approved into the SIP pursuant to the process provided

in the June 28, 1989 Federal Register are recognized as federally
enforceable. This is a useful option, but has historically been

viewed as limited in its ability to directly create emissions

limits for HAP's because of the SIP focus on criteria pollutants.

Since that option was created, however, section 112 of the

Act has been rewritten, creating significant new regulatory

requirements and conferring additional responsibilities and

authorities upon the Environmental Protection Agency (EPA) and

the States. Section 112 now mandates a wide range of activities:

source-specific preconstruction reviews, areawide approaches to

controlling risk, provisions for permitting pursuant to the 

title V permitting program, and State program provisions in

section 112(l) that are similar to aspects of the SIP program. A

result of these changes is that implementation of toxics programs

will entail the use of many of the same administrative mechanisms

as have been in use for the criteria pollutant programs.

Upon further analysis of these new program mandates and

corresponding authorities, EPA concludes that section 112 of the

Act, including section 112(l), authorizes it to recognize these

same State operating permits programs for the creation of

federally-enforceable emissions limits in support of the

implementation of section 112. Congress recognized, and

longstanding State practice confirms, that operating permits 

are core-implementing mechanisms for air quality program

requirements. This was EPA's basis for concluding that 

section 110 of the Act authorizes the recognition and approval

into the SIP of operating permits pursuant to the June 28, 1989

promulgation, even though section 110 did not expressly provide

for such a program. Similarly, broad provision of section 112(l)

for "a program for the implementation and enforcement . . . of

emission standards and other requirements for air pollutants

subject to this section" provides a sound basis for EPA

recognition of State operating permits for implementation and

enforcement of section 112 requirements in the same manner

as these permitting processes were recognized pursuant to 

section 110.

In implementing this authority to approve State operating

permits programs pursuant to section 112, it should be noted that

the specific criteria for what constitutes a federallyenforceable permit are also the same as for the existing SIP

programs. The June 28, 1989 Federal Register essentially

addressed in a generic sense the core criteria for creating

federally-enforceable emissions limits in operating permits: 

appropriate procedural mechanisms, including public notice and

opportunity for comment, statutory authority for EPA approval of

the State program, and enforceability as a practical matter. The

EPA did this in the context of SIP development, not because these

criteria are specific to the SIP, but because section 110 of the
Act was seen as our only certain statutory basis for this prior

to the 1990 Amendments. Based on the discussion above, States

can extend or develop State operating permits programs for toxics

pursuant to the criteria set forth in the June 28, 1989 Federal

Register. The EPA is also evaluating analogous opportunities to

enhance State NSR programs to address toxics and will address

this in future guidance.

This is a significant opportunity to limit directly the

emissions of HAP's. It also offers the advantage of the

administrative efficiencies that arise from using existing

administrative mechanisms, as opposed to creating additional

ones.

States are encouraged to consult with EPA Regional Offices

to discuss the details of adapting their current programs to

carry out these additional functions. The EPA will consider

State permitting programs meeting the criteria in the June 28,

1989 Federal Register as being approvable for HAP program

functions as well. States may submit their programs for

implementing this process with their part 70 program submittals,

or at such other time as they choose. The EPA has various

options for administratively recognizing these State program

submittals. The EPA plans initially to review these State

programs as SIP review actions, but with official recognition

pursuant to authorities in both sections 110 and 112. Once

rulemaking pursuant to section 112(l) of the Act is completed,

EPA expects to use the process developed in that rule for

approving State programs for HAP's. The section 112(l) process

may be especially useful prior to EPA approval and implementation

of the State title V programs. The reader may wish to refer to

the process for certain section 112(l) approvals proposed on May

19, 1993 (58 FR 29296) (see section 63.91).

The General Provisions (40 CFR part 63) establish the

applicability framework for the implementation of section 112. 

In the final rule, EPA will indicate that State operating permits

programs which meet the procedural requirements of the June 28,

1989 Federal Register can be used to develop federallyenforceable emissions limits for HAP's, thereby limiting a

source's potential to emit. In addition, after we gain

implementation experience, EPA will be evaluating the usefulness

of further rulemaking to define more specific criteria by which

this process may be used in the implementation of programs under

section 112 of the Act. Any such rulemaking could similarly be

incorporated into the General Provisions in part 63.

State-Standardized Processes Created by Rule to Establish

Source-Specific, Federally-Enforceable Emissions Limits
State air program officials have highlighted specific types

of sources that are of particular administrative concern because

of their nature and number. These include sources whose

emissions are primarily volatile organic compounds (VOC) arising

from use of solvents or coatings, such as automobile body shops. 

Another example is fuel-burning sources that have low actual

emissions because of limited hours of operation, but with the

potential to emit sulfur dioxide in amounts sufficient to cause

them to be classified as major sources. 

The EPA recognizes that emissions limitations for some

processes can be created through standardized protocols. For

example, limitations on potential to emit could be established

for certain VOC sources on the basis of limits on solvent use,

backed up by recordkeeping and by periodic reporting. Similarly,

limitations on sulfur dioxide emissions could be based on

specified sulfur content of fuel and the source's obligation to

limit usage to certain maximum amounts. Limits on hours of

operation may be acceptable for certain others sources, such as

standby boilers. In all cases, of course, the technical

requirements would need to be supported by sufficient compliance

procedures, especially monitoring and reporting, to be considered

enforceable.

The EPA concludes that such protocols could be relied on to

create federally-enforceable limitations on potential to emit if

adopted through rulemaking and approved by EPA. Although such an

approach is appropriate for only a limited number of source

categories, these categories include large numbers of sources,

such as dry cleaners, auto body shops, gas stations, printers,

and surface coaters. If such standardized control protocols are

sufficiently reliable and replicable, EPA and the public need not

be involved in their application to individual sources, as long

as the protocols themselves have been subject to notice and

opportunity to comment and have been approved by EPA into the

SIP.

To further illustrate this concept and to provide

implementation support to the States, EPA has recently released

guidance on one important way of using this process. This

document, entitled "Guidance for State Rules for Optional

Federally-Enforceable Emissions Limits Based on Volatile Organic

Compound Use," was issued by D. Kent Berry, Acting Director, Air

Quality Management Division, on October 15, 1993. It describes

approvable processes by which States can create federallyenforceable emissions limits for VOC for large numbers of sources

in a variety of source categories.

States have flexibility in their choice of administrative

process for implementation. In some cases, it may be adequate
for a State to apply these limits to individual sources through a

registration process rather than a permit. A source could simply

submit a certification to the State committing to comply with the

terms of an approved protocol. Violations of these

certifications would constitute SIP violations, in the case of

protocols approved into the SIP, and be subject to the same

enforcement mechanisms as apply in the case of any other SIP

violation. Such violations would, of course, also subject the

source to enforcement for failure to comply with the requirements

that apply to major sources, such as the requirement to obtain a

title V permit or comply with various requirements of section 112

of the Act.

Some States have also indicated an interest in more

expansive approaches to implementing this concept, such as making

presumptive determinations of control equipment efficiency with

respect to particular types of sources and pollutants. While

such approaches are more complicated and present greater numbers

of concerns in the EPA review process, they offer real potential

if properly crafted. The EPA will evaluate State proposals and

approve them if they are technically sound and enforceable as a

practical matter.

States may elect to use this approach to create federallyenforceable emissions limits for sources of HAP's as well. Based

on the same authorities in section 112 of the Act, as cited above

in the case of operating permits, EPA can officially recognize

such State program submittals. As with the operating permits

option discussed in the preceding section, EPA plans initially to

review these activities as SIP revisions, but with approval

pursuant to both sections 110 and 112 of the Act, and approve

them through the section 112(l) process when that rule is final.

Implementation Guidance

As indicated above, the creation of federally-enforceable

limits on a source's potential to emit involves the

identification of the procedural mechanisms for these efforts,

including the statutory basis for their approval by EPA, and the

technical criteria necessary for their implementation. Today's

guidance primarily addresses the procedural mechanisms available

and the statutory basis for EPA approval.

The EPA will be providing further information with respect

to the implementation of these concepts. As described above, the

first portion of this guidance, addressing limits on VOC

emissions, was issued on October 15, 1993. My office is

currently working with Regional Offices and certain States in

order to assist in the development of program options under

consideration by those States. We will provide technical and
regulatory support to other State programs and will make the

results of these efforts publicly available through the Office of

Air Quality Planning and Standards (OAQPS) Technology Transfer

Network bulletin board. 

We will provide further support through the release of a

document entitled "Enforceability Requirements for Limiting

Potential to Emit Through SIP Rules and General Permits," which

is currently undergoing final review within EPA. In addition,

EPA will be highlighting options for use of existing technical

guidance with respect to creating sound and enforceable emissions

limits. An important example of such guidance is the EPA "Blue

Book," which has been in use by States for the past 5 years as

part of their VOC control programs. 

States are encouraged to discuss program needs with their

EPA Regional Offices. The OAQPS will work with them in

addressing approvals. As indicated, additional technical

guidance for implementing these approaches is underway and will

be made publicly available soon. For further information, please

call Kirt Cox at (919) 541-5399.

cc: Air Branch Chief, Regions I-X

Regional Counsel, Regions I-X

OAQPS Division Directors

A. Eckert

M. Winer

A. Schwartz

E. Hoerath
Attachment 2 

California Example Rule 

Background

State agencies and local agencies (such as the Air Pollution

Control Districts in California) can adopt rules which place

emissions limitations on a category of sources through a

combination of limitations and compliance requirements. These

rules, if practicably enforceable, adopted with adequate public

process and approved into the SIP, can validly limit potential to

emit. Moreover, because State or local rules can cover many

sources with a single regulatory action, they are well-suited to

cover large populations of smaller sources. Many States are

finding that a combination of SIP rules or general permits for

smaller sources combined with individual permits for larger

sources provides the simplest means of ensuring that minor source

emissions are adequately limited. 

Discussion of California Rule

The EPA, the California Air Pollution Control Officers

Association and the California Air Resources Board recently

completed development of a model rule for use by the California

Air Pollution Control Districts. Because the rule contains

several innovations, including covering all source categories,

and should prove to be an inexpensive and efficient means of

limiting the potential emissions of thousands of sources in

California, the EPA believes that parts of the rule may be

helpful for other States to review and consider. 

The proposed rule is designed to place smaller sources under

annual emissions limits which restrict their "potential to emit"

and thus their exposure to "major source" requirements of the

Clean Air Act. The rule ensures compliance with the annual limit

through a series of recordkeeping and reporting requirements. 

These requirements are tapered to reduce burdens as source size

decreases. The rule creates three levels of responsibility. The

first tier requires both recordkeeping and reporting. The second

tier requires only recordkeeping with no reporting. For

instance, sources that emit only attainment pollutants which

limit their emissions to below 25 tons per year have no reporting

requirement. For sources under 5 tons per year (or 2 tons per

year for a single hazardous air pollutant), there is no specified

recordkeeping or reporting requirements although these sources

must still maintain sufficient records to demonstrate their

compliance with the rule.

To the extent possible, the recordkeeping requirements are

itemized by source category and are designed to take advantage of
records that sources are already likely to maintain. Through

these measures, the rule should assure the public that the

sources subject to the rule are properly maintaining their

emissions below major source levels, while maximizing source

flexibility and minimizing paperwork.

There are other safeguards built into the rule and in

California's overall regulatory scheme which add to the EPA's

confidence that the proposal can work. The rule applies only to

sources that agree to limit their emissions to 50 percent or less

of the major source threshold. Sources with emissions above this

level must either comply with all applicable "major source"

requirements or secure a source-specific, federally-enforceable

Air Pollution Control District permit that properly limits

emissions to levels below major source thresholds. Some sources

may be able to qualify for an "alternative operation limit" which

places simple operating limits on a source's combustion of fuel,

sale of gasoline or use of a solvent. Because of the ease with

which compliance can be tracked with operational limits, the rule

allows sources using these limits to go up to 80 percent of the

major source threshold. Either way, EPA believes that the rule

creates a sufficient compliance buffer.

Moreover, California has an extensive permit and inspection

infrastructure that increases EPA's confidence that the rule will

prove adequate for limiting emissions. California law requires

that, upon annual renewal, each permit be reviewed to determine

that the permit conditions are adequate to assure compliance with

district rules and other applicable requirements. In addition,

most California Air Pollution Control Districts have an extensive

inspection program which means that compliance with the rule will

be spot checked by inspectors visiting the source.

Finally, the rule is designed to provide smaller sources

with a federally-enforceable means of limiting their potential

emissions. The rule excludes sources that already have a

federally enforceable operating permit, and it cannot be used to

avoid complying with an permit required by the Air Pollution

Control Districts.

Aside from these general observations, EPA did have a number

of comments regarding specific language included in the rule. 

The three most significant comments are set forth below. 

However, States interested in using this rule as a model should

be aware that it was specifically designed to fit with California

State law and existing SIP provisions and that States may wish to

consider making other changes to reflect their individual needs

and requirements. 
Section 2.7: In a PM-10 nonattainment area, PM-10

precursors may need to be included when determining whether

a source is major as required by section 189(e) of the Clean

Air Act. Districts adopting this model rule should consider

whether the definition of "Major Source" in section 2.7

should be augmented to include sources of PM-10 precursors. 

Section 4.2(D): The rule allows sources using air

pollution control equipment to demonstrate compliance

through the maintenance of general records on the unit and

its operations. EPA has always been concerned with this

provision since many pollution control units are only

effective if specific operating procedures are followed. 

These specifics are best set and tracked in a sourcespecific, federally enforceable permit. For this reason,

section 1.3 sunsets the applicability of the draft rule,

after January 1, 1999, to pollution control equipment. For

the coverage to continue beyond that date, a district must

extend the provision. The EPA will disapprove the extension

if the experience with the rule demonstrates that more

specific conditions are needed to ensure that pollution

control devices are being used properly and continuously.

Section 4.2(E): In general, EPA does not favor the use of

generic or catch-all recordkeeping requirements for

compliance purposes. There is a fear that the records

necessary to show compliance for individual source

categories will not be specified by the generic provision

and thus will not be maintained. For this reason, EPA urges

the Board and the Districts to evaluate regularly whether

specific recordkeeping requirements should be developed for

additional categories. As we noted during our negotiations,

EPA will evaluate this question after the rule is in effect

for three years and the EPA may seek -- through a SIP call

or through other mechanisms -- to require additional

recordkeeping requirements if there are implementation

problems with this generic category. The districts may wish

to add to the rule a provision which would authorize them to

add recordkeeping requirements for additional source

categories without a further SIP revision.
State of California 

Proposed Rule to Limit 

Potential to Emit 

January 11, 1995 

1.0 APPLICABILITY 

1.1 General Applicability: This rule shall apply to any

stationary source which would, if it did not comply with the

limitations set forth in this rule, have the potential to

emit air contaminants equal to or in excess of the threshold

for a major source of regulated air pollutants or a major

source of hazardous air pollutants (HAPs) and which meets

one of the following conditions:

A. In every 12-month period, the actual emissions of the

stationary source are less than or equal to the

emission limitations specified in section 3.1 below; or

B. In every 12-month period, at least 90 percent of the

emissions from the stationary source are associated

with an operation limited by any one of the alternative

operational limits specified in section 6.1 below.

1.2 Stationary Source with De Minimis Emissions: The

recordkeeping and reporting provisions in sections 4.0, 5.0

and 6.0 below shall not apply to a stationary source with de

minimis emissions or operations as specified in either

subsection A or B below:

A. In every 12-month period, the stationary source emits

less than or equal to the following quantities of

emissions:

1. 5 tons per year of a regulated air pollutant

(excluding HAPs), 

2. 2 tons per year of a single HAP,

3. 5 tons per year of any combination of HAPs, and

4. 20 percent of any lesser threshold for a single

HAP that the United States Environmental

Protection Agency (U.S. EPA) may establish by

rule.

B. In every 12-month period, at least 90 percent of the

stationary source's emissions are associated with an

operation for which the throughput is less than or
equal to one of the quantities specified in subsections

1 through 9 below:

1. 1,400 gallons of any combination of solventcontaining materials but no more than 550 gallons

of any one solvent-containing material, provided

that the materials do not contain the following: 

methyl chloroform (1,1,1-trichloroethane),

methylene chloride (dichloromethane),

tetrachloroethylene (perchloroethylene), or

trichloroethylene;

2. 750 gallons of any combination of solventcontaining materials where the materials contain

the following: methyl chloroform (1,1,1-

trichloroethane), methylene chloride

(dichloromethane), tetrachloroethylene

(perchloroethylene), or trichloroethylene, but not

more than 300 gallons of any one solventcontaining material;

3. ____ gallons of solvent-containing (or volatile

organic compound containing) material used at a

paint spray unit(s);2

4. 4,400,000 gallons of gasoline dispensed from

equipment with Phase I and II vapor recovery

systems;

5. 470,000 gallons of gasoline dispensed from

equipment without Phase I and II vapor recovery

systems;

6. 1,400 gallons of gasoline combusted;

7. 16,600 gallons of diesel fuel combusted;

8. 500,000 gallons of distillate oil combusted, or

9. 71,400,000 cubic feet of natural gas combusted.

Within 30 days of a written request by the District or the

U.S. EPA, the owner or operator of a stationary source not

maintaining records pursuant to sections 4.0 or 6.0 shall

demonstrate that the stationary source's emissions or

throughput are not in excess of the applicable quantities

set forth in subsection A or B above.

2To be determined based on district SIP rules 
1.3 Provision for Air Pollution Control Equipment: The owner or

operator of a stationary source may take into account the

operation of air pollution control equipment on the capacity

of the source to emit an air contaminant if the equipment is

required by Federal, State, or District rules and

regulations or permit terms and conditions. The owner or

operator of the stationary source shall maintain and operate

such air pollution control equipment in a manner consistent

with good air pollution control practice for minimizing

emissions. This provision shall not apply after January 1,

1999 unless such operational limitation is federally

enforceable or unless the District Board specifically

extends this provision and it is submitted to the U.S. EPA. 

Such extension shall be valid unless, and until, the U.S.

EPA disapproves the extension of this provision.

1.4 Exemption, Stationary Source Subject to Rule ____ (District

Title V rule): This rule shall not apply to the following

stationary sources:

A. Any stationary source whose actual emissions,

throughput, or operation, at any time after the

effective of this rule, is greater than the quantities

specified in sections 3.1 or 6.1 below and which meets

both of the following conditions:

1. The owner or operator has notified the District at

least 30 days prior to any exceedance that s/he

will submit an application for a Part 70 permit,

or otherwise obtain federally-enforceable permit

limits, and

2. A complete Part 70 permit application is received

by the District, or the permit action to otherwise

obtain federally-enforceable limits is completed,

within 12 months of the date of notification.

However, the stationary source may be immediately

subject to applicable federal requirements, including

but not limited to, a maximum achievable control

technology (MACT) standard.

B. Any stationary source that has applied for a Part 70

permit in a timely manner and in conformance with Rule

____ (the District's Title V rule), and is awaiting

final action by the District and U.S. EPA.

C. Any stationary source required to obtain an operating

permit under Rule ____ (the District's Title V rule)

for any reason other than being a major source.
D. Any stationary source with a valid Part 70 permit.

Notwithstanding subsections B and D above, nothing in this

section shall prevent any stationary source which has had a

Part 70 permit from qualifying to comply with this rule in

the future in lieu of maintaining an application for a Part

70 permit or upon rescission of a Part 70 permit if the

owner or operator demonstrates that the stationary source is

in compliance with the emissions limitations in section 3.1

below or an applicable alternative operational limit in

section 6.1 below.

1.5 Exemption, Stationary Source with a Limitation on Potential

to Emit: this rule shall not apply to any stationary source

which has a valid operating permit with federallyenforceable conditions or other federally-enforceable limits

limiting its potential to emit to below the applicable

threshold(s) for a major source as defined in sections 2.7

and 2.8 below. 

1.6 Within three years of the effective date of Rule ____

(District Title V rule), the District shall maintain and

make available to the public upon request, for each

stationary source subject to this rule, information

identifying the provisions of this rule applicable to the

source.

1.7 This rule shall not relieve any stationary source from

complying with requirements pertaining to any otherwise

applicable preconstruction permit, or to replace a condition

or term of any preconstruction permit, or any provision of a

preconstruction permitting program.3 This does not preclude

issuance of any preconstruction permit with conditions or

terms necessary to ensure compliance with this rule.

3For example, PSD, NSR, and ATC 
2.0 DEFINITIONS 

All terms shall retain the definitions provided under 40 CFR

Part 70.2 [alternatively, the District Title V rule] unless

otherwise defined herein.

2.1 12-month period: A period of twelve consecutive months

determined on a rolling basis with a new 12-month period

beginning on the first day of each calendar month.

2.2 Actual Emissions: The emissions of a regulated air

pollutant from a stationary source for every 12-month

period. Valid continuous emission monitoring data or source

test data shall be preferentially used to determine actual

emissions. In the absence of valid continuous emissions

monitoring data or source test data, the basis for

determining actual emissions shall be: throughputs of

process materials; throughputs of materials stored; usage of

materials; data provided in manufacturer's product

specifications, material volatile organic compound (VOC)

content reports or laboratory analyses; other information

required by this rule and applicable District, State and

Federal regulations; or information requested in writing by

the District. All calculations of actual emissions shall

use U.S. EPA, California Air Resources Board (CARB) or

District approved methods, including emission factors and

assumptions. 

2.3 Alternative Operational Limit: A limit on a measurable

parameter, such as hours of operation, throughput of

materials, use of materials, or quantity of product, as

specified in Section 6.0, Alternative Operational Limit and

Requirements. 

2.4 Emission Unit: Any article, machine, equipment, operation,

contrivance or related groupings of such that may produce

and/or emit any regulated air pollutant or hazardous air

pollutant. 

2.5 Federal Clean Air Act: The federal Clean Air Act (CAA) as

amended in 1990 (42 U.S.C. section 7401 et seq.) and its

implementing regulations. 

2.6 Hazardous Air Pollutant: Any air pollutant listed pursuant

to section 112(b) of the federal Clean Air Act.

2.7 Major Source of Regulated Air Pollutants (excluding HAPs): A

stationary source that emits or has the potential to emit a

regulated air pollutant (excluding HAPs) in quantities equal
to or exceeding the lesser of any of the following

thresholds:

A. 100 tons per year (tpy) of any regulated air pollutant;

B. 50 tpy of volatile organic compounds or oxides of

nitrogen for a federal ozone nonattainment area

classified as serious, 25 tpy for an area classified as

severe, or 10 tpy for an area classified as extreme;

and

C. 70 tpy of PM10 for a federal PM10 nonattainment area

classified as serious.

Fugitive emissions of these pollutants shall be considered

in calculating total emissions for stationary sources in

accordance with 40 CFR Part 70.2 "Definitions- Major

source(2)."

2.8 Major Source of Hazardous Air Pollutants: A stationary

source that emits or has the potential to emit 10 tons per

year or more of a single HAP listed in section 112(b) of the

CAA, 25 tons per year or more of any combination of HAPs, or

such lesser quantity as the U.S. EPA may establish by rule. 

Fugitive emissions of HAPs shall be considered in

calculating emissions for all stationary sources. The

definition of a major source of radionuclides shall be

specified by rule by the U.S. EPA .

2.9 Part 70 Permit: An operating permit issued to a stationary

source pursuant to an interim, partial or final Title V

program approved by the U.S. EPA.

2.10 Potential to Emit: The maximum capacity of a stationary

source to emit a regulated air pollutant based on its

physical and operational design. Any physical or

operational limitation on the capacity of the stationary

source to emit a pollutant, including air pollution control

equipment and restrictions on hours of operation or on the

type or amount of material combusted, stored, or processed,

shall be treated as part of its design only if the

limitation is federally enforceable. 

2.11 Process Statement: An annual report on permitted emission

units from an owner or operator of a stationary source

certifying under penalty of perjury the following: 

throughputs of process materials; throughputs of materials

stored; usage of materials; fuel usage; any available

continuous emissions monitoring data; hours of operation;
and any other information required by this rule or requested

in writing by the District.

2.12 Regulated Air Pollutant: The following air pollutants are

regulated:

A. Oxides of nitrogen and volatile organic compounds;

B. Any pollutant for which a national ambient air quality

standard has been promulgated;

C. Any Class I or Class II ozone depleting substance

subject to a standard promulgated under Title VI of the

federal Clean Air Act;

D. Any pollutant that is subject to any standard

promulgated under section 111 of the federal Clean Air

Act; and

E. Any pollutant subject to a standard or requirement

promulgated pursuant to section 112 of the federal

Clean Air Act, including:

1. Any pollutant listed pursuant to section 112(r)

(Prevention of Accidental Releases) shall be

considered a regulated air pollutant upon

promulgation of the list.

2. Any HAP subject to a standard or other requirement

promulgated by the U.S. EPA pursuant to section

112(d) or adopted by the District pursuant to

112(g) and (j) shall be considered a regulated air

pollutant for all sources or categories of

sources: 1) upon promulgation of the standard or

requirement, or 2) 18 months after the standard or

requirement was scheduled to be promulgated

pursuant to section 112(e)(3).

3. Any HAP subject to a District case-by-case

emissions limitation determination for a new or

modified source, prior to the U.S. EPA

promulgation or scheduled promulgation of an

emissions limitation shall be considered a

regulated air pollutant when the determination is

made pursuant to section 112(g)(2). In case-bycase emissions limitation determinations, the HAP

shall be considered a regulated air pollutant only

for the individual source for which the emissions

limitation determination was made. 
3.0 EMISSION LIMITATIONS 

3.1 Unless the owner or operator has chosen to operate the

stationary source under an alternative operational limit

specified in section 6.1 below, no stationary source

subject to this rule shall emit in every 12-month period

more than the following quantities of emissions:

A. 50 percent of the major source thresholds for regulated

air pollutants (excluding HAPs),

B. 5 tons per year of a single HAP,

C. 12.5 tons per year of any combination of HAPs, and 

D. 50 percent of any lesser threshold for a single HAP as

the U.S. EPA may establish by rule.

3.2 The APCO shall evaluate a stationary source's compliance

with the emission limitations in section 3.1 above as part

of the District's annual permit renewal process required by

Health & Safety Code section 42301(e). In performing the

evaluation, the APCO shall consider any annual process

statement submitted pursuant to Section 5.0, Reporting

Requirements. In the absence of valid continuous emission

monitoring data or source test data, actual emissions shall

be calculated using emissions factors approved by the U.S.

EPA , CARB, or the APCO. 

3.3 Unless the owner or operator has chosen to operate the

stationary source under an alternative operational limit

specified in section 6.1 below, the owner or operator of a

stationary source subject to this rule shall obtain any

necessary permits prior to commencing any physical or

operational change or activity which will result in actual

emissions that exceed the limits specified in section 3.1

above.

4.0 RECORDKEEPING REQUIREMENTS 

Immediately after adoption of this rule, the owner or

operator of a stationary source subject to this rule shall

comply with any applicable recordkeeping requirements in

this section. However, for a stationary source operating

under an alternative operational limit, the owner or

operator shall instead comply with the applicable

recordkeeping and reporting requirements specified in

Section 6.0, Alternative Operational Limit and Requirements. 

The recordkeeping requirements of this rule shall not
replace any recordkeeping requirement contained in an

operating permit or in a District, State, or Federal rule or

regulation. 

4.1. A stationary source previously covered by the provisions in

section 1.2 above shall comply with the applicable

provisions of section 4.0 above and sections 5.0 and 6.0

below if the stationary source exceeds the quantities

specified in section 1.2.A above.

4.2 The owner or operator of a stationary source subject to this

rule shall keep and maintain records for each permitted

emission unit or groups of permitted emission units4

sufficient to determine actual emissions. Such information

shall be summarized in a monthly log, maintained on site for

five years, and be made available to District, CARB, or U.S.

EPA staff upon request.

A. Coating/Solvent Emission Unit

The owner or operator of a stationary source subject to

this rule that contains a coating/solvent emission

unit or uses a coating, solvent, ink or adhesive shall

keep and maintain the following records:

1. A current list of all coatings, solvents, inks and

adhesives in use. This list shall include: 

information on the manufacturer, brand, product

name or code, VOC content in grams per liter or

pounds per gallon, HAPS content in grams per liter

or pounds per gallon, or manufacturer's product

specifications, material VOC content reports or

laboratory analyses providing this information;

2. A description of any equipment used during and

after coating/solvent application, including type,

make and model; maximum design process rate or

throughput; control device(s) type and description

(if any); and a description of the coating/solvent

application/drying method(s) employed;

3. A monthly log of the consumption of each solvent

(including solvents used in clean-up and surface

preparation), coating, ink and adhesive used; and

4In some cases it may be appropriate to keep records on groups of emission units which are 

connected in series. Examples are internal combustion engines in the oil fields with a common 

fuel line, or a series of paint spray booths with a common feed. 
4. All purchase orders, invoices, and other documents

to support information in the monthly log.

B. Organic Liquid Storage Unit

The owner or operator of a stationary source subject to

this rule that contains a permitted organic liquid

storage unit shall keep and maintain the following

records: 

1. A monthly log identifying the liquid stored and

monthly throughput; and

2. Information on the tank design and specifications

including control equipment. 

C. Combustion Emission Unit

The owner or operator of a stationary source subject to

this rule that contains a combustion emission unit

shall keep and maintain the following records:

1. Information on equipment type, make and model,

maximum design process rate or maximum power

input/output, minimum operating temperature (for

thermal oxidizers) and capacity, control device(s)

type and description (if any) and all source test

information; and 

2. A monthly log of hours of operation, fuel type,

fuel usage, fuel heating value (for non-fossil

fuels; in terms of BTU/lb or BTU/gal), percent

sulfur for fuel oil and coal, and percent nitrogen

for coal.

D. Emission Control Unit

The owner or operator of a stationary source subject to

this rule that contains an emission control unit shall

keep and maintain the following records:

1. Information on equipment type and description,

make and model, and emission units served by the

control unit;

2. Information on equipment design including where

applicable: pollutant(s) controlled; control

effectiveness; maximum design or rated capacity;

inlet and outlet temperatures, and concentrations

for each pollutant controlled; catalyst data
(type, material, life, volume, space velocity,

ammonia injection rate and temperature); baghouse

data (design, cleaning method, fabric material,

flow rate, air/cloth ratio); electrostatic

precipitator data (number of fields, cleaning

method, and power input); scrubber data (type,

design, sorbent type, pressure drop); other design

data as appropriate; all source test information;

and

3. A monthly log of hours of operation including

notation of any control equipment breakdowns,

upsets, repairs, maintenance and any other

deviations from design parameters.

E. General Emission Unit

The owner or operator of a stationary source

subject to this rule that contains an emission

unit not included in subsections A, B or C above

shall keep and maintain the following records:

1. Information on the process and equipment

including the following: equipment type,

description, make and model; maximum design

process rate or throughput; control device(s)

type and description (if any); 

2. Any additional information requested in

writing by the APCO;

3. A monthly log of operating hours, each raw

material used and its amount, each product

produced and its production rate; and 

4. Purchase orders, invoices, and other

documents to support information in the

monthly log. 

5.0 REPORTING REQUIREMENTS 

5.1 At the time of annual renewal of a permit to operate under

Rule _____ (the District's general permitting rule), each

owner or operator of a stationary source subject to this

rule shall submit to the District a process statement. The

statement shall be signed by the owner or operator and

certify that the information provided is accurate and true.
5.2 For the purpose of determining compliance with this rule,

this requirement shall not apply to stationary sources which

emit in every 12-month period less than or equal to the

following quantities:

A. For any regulated air pollutant (excluding HAPs),

1. 25 tons per year including a regulated air

pollutant for which the District has a federal

area designation of attainment, unclassified,

transitional, or moderate nonattainment,

2. 15 tons per year for a regulated air pollutant for

which the District has a federal area designation

of serious nonattainment,

3. 6.25 tons per year for a regulated air pollutant

for which the District has a federal area

designation of severe nonattainment, 

B. 2.5 tons per year of a single HAP,

C. 6.25 tons per year of any combination of HAPs, and

D. 25 percent of any lesser threshold for a single HAP as

the U.S. EPA may establish by rule.

5.3 A stationary source previously covered by provisions in

section 5.2 above shall comply with the provisions of

section 5.1 above if the stationary source exceeds the

quantities specified in section 5.2.

5.4 Any additional information requested by the APCO under

section 5.1 above shall be submitted to the APCO within 30

days of the date of request.
6.0 ALTERNATIVE OPERATIONAL LIMIT AND REQUIREMENTS 

[The District may propose additional alternative operational

limits]

The owner or operator may operate the permitted emission

units at a stationary source subject to this rule under any

one alternative operational limit, provided that at least 90

percent of the stationary source's emissions in every 12-

month period are associated with the operation(s) limited by

the alternative operational limit. 

6.1 Upon choosing to operate a stationary source subject to this

rule under any one alternative operational limit, the owner

or operator shall operate the stationary source in

compliance with the alternative operational limit and comply

with the specified recordkeeping and reporting requirements.

A. The owner or operator shall report within 24 hours to

the APCO any exceedance of the alternative operational

limit.

B. The owner or operator shall maintain all purchase

orders, invoices, and other documents to support

information required to be maintained in a monthly log. 

Records required under this section shall be maintained

on site for five years and be made available to

District or U.S. EPA staff upon request.

C. Gasoline Dispensing Facility Equipment with Phase I and

II Vapor Recovery Systems

The owner or operator shall operate the gasoline

dispensing equipment in compliance with the following

requirements:

1. No more than 7,000,000 gallons of gasoline shall

be dispensed in every 12-month period.

2. A monthly log of gallons of gasoline dispensed in

the preceding month with a monthly calculation of

the total gallons dispensed in the previous 12

months shall be kept on site. 

3. A copy of the monthly log shall be submitted to

the APCO at the time of annual permit renewal. 

The owner or operator shall certify that the log

is accurate and true.

D. Degreasing or Solvent-Using Unit
The owner or operator shall operate the degreasing or

solvent-using unit(s) in compliance with the following

requirements:

1. a. If the solvents do not include methyl

chloroform (1,1,1-trichloroethane), methylene

chloride (dichloromethane),

tetrachloroethylene (perchloroethylene), or

trichloroethylene, no more than 5,400 gallons

of any combination of solvent-containing

materials and no more than 2,200 gallons of

any one solvent-containing material shall be

used in every 12-month period,.

b. If the solvents include methyl chloroform

(1,1,1-trichloroethane), methylene chloride

(dichloromethane), tetrachloroethylene

(perchloroethylene), or trichloroethylene, no

more than 2,900 gallons of any combination of

solvent-containing materials and no more than

1,200 gallons of any one solvent-containing

material shall be used in every 12-month

period. 

2. A monthly log of amount and type of solvent used

in the preceding month with a monthly calculation

of the total gallons used in the previous 12

months shall be kept on site. 

3. A copy of the monthly log shall be submitted to

the APCO at the time of annual permit renewal. 

The owner or operator shall certify that the log

is accurate and true.

E. Paint Spraying Unit5

The owner or operator shall operate the paint spraying

unit(s) in compliance with the following requirements:

1. The total usage rate of all VOC-containing

materials, including but not limited to, coatings,

thinners, reducers, and cleanup solution shall not

exceed _____ gallons in every 12-month period. 

2. A monthly log of the gallons of VOC-containing

materials used in the preceding month with a

5To be determined based on District SIP rules 
monthly calculation of the total gallons used in

the previous 12 months shall be kept on site. 

3. A copy of the monthly log shall be submitted to

the APCO at the time of annual permit renewal. 

The owner or operator shall certify that the log

is accurate and true.

F. Diesel-Fueled Emergency Standby Engine(s) with Output

Less Than 1,000 Brake Horsepower

[Depending on the District's federal ozone attainment

status, the District will adopt either subsection 1.a,

1.b, or 1.c below.]

The owner or operator shall operate the emergency

standby engine(s) in compliance with the following

requirements:

1. a. For a federal ozone area designation of

attainment, unclassified, transitional, or

moderate nonattainment, the emergency standby

engine(s) shall not operate more than 5,200

hours in every 12-month period and shall not

use more than 265,000 gallons of diesel fuel

in every 12-month period.

b. For a federal ozone nonattainment area

classified as serious, the emergency standby

engine(s) shall not operate more than 2,600

hours in every 12-month period and shall not

use more than 133,000 gallons of diesel fuel

in every 12-month period.

c. For a federal ozone nonattainment area

classified as severe, the emergency standby

engine(s) shall not operate more than 1,300

hours in 12-month period and shall not use

more than 66,000 gallons of diesel fuel in

every 12-month period.

2. A monthly log of hours of operation, gallons of

fuel used, and a monthly calculation of the total

hours operated and gallons of fuel used in the

previous 12 months shall be kept on site. 

3. A copy of the monthly log shall be submitted to

the APCO at the time of annual permit renewal. 

The owner or operator shall certify that the log

is accurate and true.
6.2 The owner or operator of a stationary source subject to this

rule shall obtain any necessary permits prior to commencing

any physical or operational change or activity which will

result in an exceedance of an applicable operational limit

specified in section 6.1 above.

7.0 VIOLATIONS 

7.1 Failure to comply with any of the applicable provisions of

this rule shall constitute a violation of this rule. Each

day during which a violation of this rule occurs is a

separate offense.

7.2 A stationary source subject to this rule shall be subject to

applicable federal requirements for a major source,

including Rule ____ (District Title V rule) when the

conditions specified in either subsections A or B below,

occur:

A. Commencing on the first day following every 12-month

period in which the stationary source exceeds a limit

specified in section 3.1 above and any applicable

alternative operational limit specified in section 6.1,

above, or

B. Commencing on the first day following every 12-month

period in which the owner or operator can not

demonstrate that the stationary source is in compliance

with the limits in section 3.1 above or any applicable

alternative operational limit specified in section 6.1

above.
Attachment 3

November 2, 1994 Letter Describing Use of Minor NSR Programs

Mr. Jason Grumet

Executive Director, Northeast States

for Coordinated Air Use Management

129 Portland Street

Boston, Massachusetts 02114

Dear Mr. Grumet:

This is in response to Mr. Michael Bradley's March 22, 1994

letter to Mary Nichols seeking clarification of the Federal

enforceability of State's existing minor new source review (NSR)

programs. It is my understanding that some of the NESCAUM States

are interested in using their existing minor NSR programs to

limit a source's potential to emit so as to allow sources to

legally avoid being considered a major source for title V

purposes. 

In my November 3, 1993 memorandum entitled "Approaches to

Creating Federally-Enforceable Emission Limits," I described

approaches that States could use to limit a source's potential to

emit for title V purposes. While a number of approaches are

acceptable, the Environmental Protection Agency (EPA) has

promoted the use of State operating permits programs approved

under sections 110 and 112(l), pursuant to the criteria set forth

in the June 28, 1989 Federal Register. Among other things, these

criteria include an opportunity for public and EPA review and

require that permit conditions be practically enforceable. 

Several States have followed EPA's recommendation and have either

adopted these requirements or are in the process of doing so.

The Agency recognizes the use of other approaches as well. 

In response to your question, EPA's position is that minor NSR

permits issued under programs that have already been approved

into the State implementation plan (SIP) are federally

enforceable. Thus, EPA allows the use of federally-enforceable

minor NSR permits to limit a source's potential to emit provided

that the scope of a State's program allows for this and that the

minor NSR permits are in fact enforceable as a practical matter. 

Because minor NSR programs are essentially preconstruction

review programs for new sources and modifications to existing

sources, minor NSR programs can generally be used to limit a 
2

source's potential emissions when such limits are taken in

conjunction with a preconstruction permit action. In addition,

please note that the term "modification" generally encompasses

both physical changes and changes in the method of operation at

an existing source (see Clean Air Act section 111(a)(4)). Thus,

the scope of some, though not all, minor NSR programs is broad

enough to be used to also limit a source's potential to emit for

nonconstruction-related events. This occurs where the

modification component of State programs extends to both physical

changes and changes in the method of operation. In these cases,

where a voluntary reduction in the method of operation (e.g.,

limit in hours of operation or production rate) by itself is

considered a modification for minor NSR permitting, a source may

reduce its hours of operation or production rate and make such a

change federally enforceable through limits in its minor NSR

permit. 

Some States' minor NSR programs are written so as to

preclude a source from limiting its potential to emit absent an

increase in emissions. There may be other limitations on the

scope of these programs as well. Since there is considerable

variation among State minor NSR programs, a review of any

individual State program would be necessary to determine its

ability to limit a source's potential to emit. It may be

beneficial for States to contact the appropriate EPA Regional

Office if there are questions about the scope of the SIP-approved

minor NSR program.

Minor NSR programs have generally been used in the past to

limit a source's potential to emit for criteria pollutants. 

There is a growing need for sources to limit their potential to

emit for toxic pollutants as well. The EPA is currently

considering ways in which a State may limit the potential to emit

of toxic pollutants, including possible uses of existing minor

NSR programs. I plan to keep you and others aware of our efforts

in this regard.

You should also be aware that a recent court ruling has

called into question the Federal enforceability of a State minor

NSR permit that does not meet the public participation

requirements of current EPA regulations despite SIP approval of

the State's program [see United States v. Marine Shale

Processors, No. 90-1240 (E.D. La.) (bench ruling), June 15,

1994]. In that case involving extensive alleged violations of

the permit terms, the court held that EPA could not enforce the

terms of the minor NSR permit. The court subsequently ruled that

the company could not rely on the permit to limit its potential

to emit, and thus was liable for having failed to obtain a major 
3

NSR permit. The outcome of this case suggests that States should

proceed cautiously in relying on minor NSR programs to limit

potential to emit where the program does not actually provide

public participation.

In summary, EPA has provided guidance on approaches that are

available to limit a source's potential to emit. The Agency

recommends approaches that meet the criteria set forth in the

June 28, 1989 Federal Register. Many States are taking action to

adopt such programs. With respect to minor NSR permits, EPA

believes that permits conditions issued in accordance with

existing State minor NSR programs that have been approved into

the SIP, and which are enforceable as a practical matter, are

federally enforceable and can be used to limit potential to emit. 

Caution is advised, however, with respect to permits that do not

meet procedural requirements. These programs are primarily

preconstruction review programs although in many cases they can

also limit a source's potential to emit in conjunction with

operational changes. 

As you have noted, title V issues are complicated and

resource intensive. In order for the title V program to be

successfully implemented, it is important that States and EPA 

work cooperatively in developing operating permits programs. 

Your comments and recommendations on program development issues

are welcome. 

We appreciate this opportunity to be of service and trust

that this information will be helpful to you.

Sincerely,

John S. Seitz

Director

Office of Air Quality Planning

and Standards

cc: Air Division Director, Regions I-X
Attachment 4

January 25, 1995 Guidance on Practicable Enforceability

SUBJECT: Guidance on Enforceability Requirements for Limiting

Potential to Emit through SIP and §112 Rules and

General Permits

FROM: Kathie A. Stein, Director

Air Enforcement Division

TO: Director, Air, Pesticides and Toxics 

Management Division, Regions I and IV

Director, Air and Waste Management Division,

Region II

Director, Air, Radiation and Toxics Division,

Region III

Director, Air and Radiation Division,

Region V

Director, Air, Pesticides and Toxics Division,

Region VI

Director, Air and Toxics Division,

Regions VII, VIII, IX, and X

Attached is a guidance document developed over the past year

by the former Stationary Source Compliance Division in

coordination with the Air Enforcement Division, Office of Air

Quality Planning and Standards, OAR's Office of Policy Analysis

and Review, and the Office of General Counsel, as well as with

significant input from several Regions. 

A number of permitting authorities have begun discussions

with or have submitted programs for review by EPA that would

provide alternative mechanisms for limiting potential to emit. 

Several authorities have submitted SIP rules and at least one

State has been developing a State general permit approach. We

believe that this guidance is important to assist the EPA Regions

as well as States in approving and developing such approaches. 

For additional information regarding this guidance, please

contact me or Clara Poffenberger of my staff at (202) 564-8709.

cc: John Rasnic, Director

Manufacturing, Energy, and Transportation Division

Office of Compliance

Air Branch Chiefs, Regions I - X
Enforceability Requirements for Limiting Potential to Emit 

Through SIP and §112 Rules and General Permits 

Introduction

As several EPA guidances describe, there are several

mechanisms available for sources to limit potential to emit. EPA

guidances have also described the importance of practical

enforceability of the means used to limit potential to emit. 

This guidance is intended to provide additional guidance on

practical enforceability for such limits. We provide references

for guidances on practical enforceability for permits and rules

in general and provide guidance in this document for application

of the same principles to "limitations established by rule or

general permit," as described in the guidance document issued

January 25, 1995, entitled "Options for Limiting Potential to

Emit (PTE) of a Stationary Source under section 112 and Title V

of the Clean Air Act (Act)." The description is as follows:
Limitations established by rules. For less complex

plant sites, and for source categories involving

relatively few operations that are similar in nature,

case-by-case permitting may not be the most

administratively efficient approach to establishing

federally enforceable restrictions. One approach that

has been used is to establish a general rule which

creates federally enforceable restrictions at one time

for many sources (these rules have been referred to as

"prohibitory" or "exclusionary" rules1). The concept

of exclusionary rules is described in detail in the

November 3, 1993 memorandum ["Approaches to Creating

Federally Enforceable Emissions Limits," from John S.

Seitz]. A specific suggested approach for VOC limits

by rule was described in EPA's memorandum dated October

15, 1993 entitled "Guidance for State Rules for

Optional Federally-Enforceable Emissions Limits Based

Upon Volatile Organic Compound (VOC) Use." An example

of such an exclusionary rule is a model rule developed

for use in California. (The California model rule is

attached, along with a discussion of its applicability

to other situations--see Attachment 2). Exclusionary

rules are included in a State's SIP or 112 program and

generally become effective upon approval by the EPA. 

General permits. A concept similar to the exclusionary

rule is the establishment of a general permit for a

given source type. A general permit is a single permit

that establishes terms and conditions that must be

complied with by all sources subject to that permit. 

The establishment of a general permit could provide for

emission limitations in a one-time permitting process,

and thus avoid the need to issue separate permits for

each source. Although this concept is generally

thought of as an element of Title V permit programs,

there is no reason that a State or local agency could

not submit a general permit program as a SIP submittal

aimed at creating synthetic minor sources. 

Additionally, FESOP [Federally Enforceable State

Operating Permit, usually referring to Title I State

Operating Permit Programs approved under the criteria

established by EPA in the June 28, 1989 Federal

Register notice, 54 FR 27274] programs can include

general permits as an element of the FESOP program

being approved into the SIP. The advantage of a SIP

general permit, when compared to an exclusionary rule,

1 The EPA prefers the term "exclusionary rule" in that this

phrase is a less ambiguous description of the overall purpose of

these rules. 
is that upon approval by the EPA of the State's general

permit program, a general permit could be written for

an additional source type without triggering the need

for the formal SIP revision process. (January 25, 1995,

Seitz and Van Heuvelen memorandum, page 4.)

SIP or § 112 Rules

Source-category standards approved in the SIP or under 112,

if enforceable as a practical matter, can be used as federally

enforceable limits on potential to emit. Such provisions require

public participation and EPA review. Once a specific source

qualifies under the applicability requirements of the sourcecategory rule, additional public participation is not required to

make the limits federally enforceable as a matter of legal

sufficiency since the rule itself underwent public participation

and EPA review. The rule must still be enforceable as a

practical matter in order to be considered federally enforceable. 

A source that violates this type of rule limiting potential to

emit below major source thresholds or is later determined not to

qualify for coverage under the rule, could be subject to

enforcement action for violation of the rule and for constructing

or operating without a proper permit (a part 70 permit, a New

Source Review permit, or operating without meeting §112

requirements, or any combination thereof).

General Permits

The Title V regulations set out provisions for general

permits covering numerous similar sources. The primary purpose

of general permits is to provide a permitting alternative where

the normal permitting process would be overly burdensome, such as

for area sources under section 112. General permits may be

issued to cover any category of numerous similar sources,

including major sources, provided that such sources meet certain

criteria laid out in 40 CFR part 70. Sources may be issued

general permits strictly for the purpose of avoiding

classification as a major source. In other words, general

permits may be used to limit the potential to emit for numerous

similar sources. However, general permits must also meet both

legal and practical federal enforceability requirements. 

With respect to legal sufficiency, the operating permit

regulations provide that once the general permit has been issued

after opportunity for public participation and EPA and affected

State review, the permitting authority may grant or deny a

source’s request to be covered by a general permit without

further public participation or EPA or affected State review. 

The action of granting or denying the source’s request is not

subject to judicial review. A general permit does not carry a
permit shield. A source may be subject to enforcement action for

operating without a part 70 permit if the source is later

determined not to qualify for coverage under the general permit. 

Sources covered by general permits must comply with all part 70

requirements. 

State SIP or 112(l) General Permits

Another mechanism available to limit potential to emit is a

general permit program approved into the SIP or under section

112(l), the hazardous air pollutant program authority. This

mechanism allows permitting authorities to issue and revise

general permits consistent with SIP or 112(l) program

requirements without going through the SIP or 112(l) approval

process for each general permit or revision of a general permit. 

The program is also separate from title V, like title I state

operating permits, and issuance and revisions of the permits are

not required to comply with title V procedures. 

Once a program is approved, issuing and revising general

permits should be significantly less burdensome and timeconsuming for State legislative and rulemaking authorities. The

EPA review should also be less burdensome and time-consuming. 

After a program is approved, permitting authorities have the

flexibility to submit and issue general permits as needed rather

than submitting them all at once as part of a SIP submittal. 

Given the reduced procedural burden, permitting authorities

should be able to issue general permits to small groups or

categories or sources rather than attempt to cover broad

categories with a generic rule. We anticipate that specific

permit requirements for general permits may be readily developed

with the assistance of interested industry groups.

The State general permit approach may allow sources to meet

the federal enforceability requirements more easily than other

approaches. However, to use this approach, States must have a

federally enforceable program that provides the State the

authority to issue such permits; to accomplish this, EPA must

approve the program into the SIP or pursuant to section 112(l) of

the Clean Air Act.

Enforceability Principles

In 1989, in response to challenges from the Chemical

Manufacturers Association and other industry groups, EPA

reiterated its position that controls and limitations used to

limit a source's potential to emit must be federally enforceable. 

See 54 FR 27274 (June 28, 1989). Federally enforceable limits

can be established by Clean Air Act programs such as NSPS,

NESHAPs, MACTs, and SIP requirements. However, source-specific
limits are generally set forth in permits. Generally, to be 

considered federally enforceable, the permitting program must be 

approved by EPA into the SIP and include provisions for public 

participation. In addition, permit terms and conditions must be 

practicably enforceable to be considered federally enforceable. 

EPA provided specific guidance on federally enforceable permit 

conditions in a June 13, 1989 policy memo ?Limiting Potential to 

Emit in New Source Permitting” from John Seitz and in the June 

28, 1989 Federal Register notice (54 FR 27274). Additional 

guidance can also be found in United States v. Louisiana Pacific, 

682 F. Supp. 1122 (D. Colo. 1987), 682 F. Supp 1141 (D. Colo. 

1988), which led to these guidance statements and a number of 

other memoranda covering practicable enforceability as it relates 

to rolling averages, short-term averages, and emission caps. See 

?Use of Long Term Rolling Averages to Limit Potential to Emit,” 

from John B. Rasnic to David Kee, February 24, 1992; ?Limiting 

Potential to Emit” from Mamie Miller to George Czerniak, August 

5, 1992; ?Policy Determination on Limiting Potential to Emit for 

Koch Refining Company’s Clean Fuels Project”, from John B. Rasnic 

to David Kee, March 13, 1992; and ?3M Tape Manufacturing Division 

Plant, St. Paul, Minnesota” from John B. Rasnic to David Kee, 

July 14, 1992. 

In 1987, EPA laid out enforceability criteria that SIP rules 

must meet. See ?Review of State Implementation Plans and 

Revisions for Enforceability and Legal Sufficiency” from Michael 

Alushin, Alan Eckert, and John Seitz, September 3, 1987 (1987 SIP 

memo). The criteria include clear statements as to 

applicability, specificity as to the standard that must be met, 

explicit statements of the compliance time frames (e.g. hourly, 

daily, monthly, or 12-month averages, etc.), that the time frame 

and method of compliance employed must be sufficient to protect 

the standard involved, recordkeeping requirements must be 

specified, and equivalency provisions must meet certain 

requirements. 

Based on these precedents, this guidance describes six

enforceability criteria which a rule or a general permit must

meet to make limits enforceable as a practical matter. In

general, practical enforceability for a source-specific permit

term means that the provision must specify (1) a technically

accurate limitation and the portions of the source subject to the

limitation; (2) the time period for the limitation (hourly,

daily, monthly, annually); and (3) the method to determine

compliance including appropriate monitoring, recordkeeping and

reporting. For rules and general permits that apply to

categories of sources, practical enforceability additionally

requires that the provision (4) identify the categories of

sources that are covered by the rule; (5) where coverage is

optional, provide for notice to the permitting authority of the
source's election to be covered by the rule; and (6) recognize

the enforcement consequences relevant to the rule. 

This guidance will address requirements (4) and (5) first as

they are concepts that are unique to rules and general permits. 

A. Specific Applicability

Rules and general permits designed to limit potential to

emit must be specific as to the emission units or sources covered

by the rule or permit. In other words, the rule or permit must

clearly identify the category(ies) of sources that qualify for

the rule’s coverage. The rule must apply to categories of

sources that are defined specifically or narrowly enough so that

specific limits and compliance monitoring techniques can be

identified and achieved by all sources in the categories defined. 

A rule or general permit that covers a homogeneous group of

sources should allow standards to be set that limit potential to

emit and provide the specific monitoring requirements.

(Monitoring is more fully addressed in section D.) The State can

allow for generic control efficiencies where technically sound

and appropriate, depending on the extent of the application and

ability to monitor compliance with resultant emission limits. 

Similarly, specific and narrow applicability may allow generic

limits on material usage or limits on hours of operation to be

sufficient. For example, a rule or general permit that applies

to fossil-fuel fired boilers of a certain size may allow for

limits on material usage, such as fuel-type and quantity. A rule

or general permit that applies only to standby diesel generators

or emergency generators may allow restrictions on hours of

operation to limit potential to emit. The necessary compliance

terms (i.e., monitoring or recordkeeping) associated with any of

these limits, such as with hours of operation, can readily be

specified in the rule or the general permit itself.

General permits under Title V are assumed to include this

enforceability principle because the Part 70 regulations set out

specific criteria that States should consider in developing their

general permit provisions (See 57 FR 32278). These factors

include requirements that 

?categories of sources covered by general permits 

should be generally homogenous in terms of operations, 

processes, and emissions. All sources in the category 

should have essentially similar operations or processes 

and emit pollutants with similar characteristics.” 

Another factor stated is ?sources should be subject to the same 

or substantially similar requirements governing operation, 

emissions, monitoring, reporting, or recordkeeping.” Examples of 
source categories appropriate for general permits include: 

degreasers, dry cleaners, small heating systems, sheet fed

printers, and VOC storage tanks (see 57 FR 32278). 

B. Reporting or Notice to Permitting Authority

The rule or general permit should provide specific reporting

requirements as part of the compliance method. Although the

compliance method for all sources must include recordkeeping

requirements, the permitting authority may make a determination

that reporting requirements for small sources would provide

minimal additional compliance assurance. Where ongoing reporting

requirements are determined not to be reasonable for a category

of sources, the rule or general permit should still provide that

the source notify the permitting authority of its coverage by the

rule or the permit. In the limited situation where all the

sources described in a source category are required to comply

with the all of the provisions of a rule or general permit,

notice is not needed. However, where there are no reporting

requirements and no opt-in provisions, the permitting authority

must provide the public with the names and locations of sources

subject to the rule or permit.

For Title V general permits, Part 70 requires sources to

submit an application for a general permit which must be approved

or disapproved by the permitting authority. For SIP or §112

rules and SIP or §112 general permits, in response to receiving

the notice or application, the permitting authority may issue an

individual permit, or alternatively, a letter or certification. 

The permitting authority may also determine initially whether it

will issue a response for each individual application or notice,

and may initially specify a reasonable time period after which a

source that has submitted an application or notice will be deemed

to be authorized to operate under the general permit or SIP or

§112 rule.
C. Specific Technically Accurate Limits

The rule or general permit issued pursuant to the SIP or

§112 must specify technically accurate limits on the potential to

emit. The rule or general permit must clearly specify the limits

that apply, and include the specific associated compliance

monitoring. (The compliance monitoring requirements are

discussed further in the next section.) The standards or limits

must be technically specific and accurate to limit potential to

emit, identifying any allowed deviations.

The 1987 policy on SIP enforceability states that 

limitations ?must be sufficiently specific so that a source is 

fairly on notice as to the standard it must meet.” For example, 

?alternative equivalent technique” provisions should not be 

approved without clarification concerning the time period over 

which equivalency is measured as well as whether the equivalency 

applies on a per source or per line basis or is facility-wide. 

Further, for potential to emit limitations, the standards

set must be technically sufficient to provide assurance to EPA

and the public that they actually represent a limitation on the

potential to emit for the category of sources identified. Any

presumption for control efficiency must be technically accurate

and the rule must provide the specific parameters as enforceable

limits to assure that the control efficiency will be met. For

example, rules setting presumptive efficiencies for incineration

controls applied to a specific or broad category must state the

operating temperature limits or range, the air flow, or any other

parameters that may affect the efficiency on which the

presumptive efficiency is based. Similarly, material usage

limits such as fuel limits, as stated above, require specifying

the type of fuel and may require specifying other operating

parameters. 

A rule that allows sources to submit the specific parameters

and associated limits to be monitored may not be enforceable

because the rule itself does not set specific technical limits. 

The submission of these voluntarily accepted limits on parameters

or monitoring requirements would need to be federally

enforceable. Absent a source-specific permit and appropriate

review and public participation of the limits, such a rule is not

consistent with the EPA’s enforceability principles. 

D. Specific Compliance Monitoring

The rule must specify the methods to determine compliance. 

Specifically, the rule must state the monitoring requirements,

recordkeeping requirements, reporting requirements, and test

methods as appropriate for each potential to emit limitation; and
clarify which methods are used for making a direct determination 

of compliance with the potential to emit limitations. 

?Monitoring” refers to many different types of data collection, 

including continuous emission or opacity monitoring, and 

measurements of various parameters of process or control devices 

(e.g. temperature, pressure drop, fuel usage) and recordkeeping 

of parameters that have been limited, such as hours of operation, 

production levels, or raw material usage. Without a verifiable 

plantwide emission limit, verifiable emission limits must be 

assigned to each unit or group of units subject to the rule or 

general permit. Where monitoring cannot be used to determine 

emissions directly, limits on appropriate operating parameters 

must be established for the units or source, and monitoring must 

verify compliance with those limits. The monitoring must be 

sufficient to yield data from the relevant time period that is 

representative of the source’s compliance with the standard or 

limit. Continuous emissions monitoring, especially in the case 

of smaller sources, is not required. 

E. Practicably Enforceable Averaging Times

The averaging time for all limits must be practicably 

enforceable. In other words, the averaging time period must 

readily allow for determination of compliance. EPA policy 

expresses a preference toward short term limits, generally daily 

but not to exceed one month. However, EPA policy allows for 

rolling limits not to exceed 12 months or 365 days where the 

permitting authority finds that the limit provides an assurance 

that compliance can be readily determined and verified. See June 

13, 1989 ?Guidance on Limiting Potential to Emit,” February 24, 

1992 Memorandum ?Use of Long Term Rolling Averages to Limit 

Potential to Emit” from John Rasnic to David Kee, and March 13, 

1992 ?Policy Determination on Limiting Potential to Emit for Koch 

Refining Company’s Clean Fuels Project” from John B. Rasnic to 

David Kee, stating that determinations to allow an annual rolling 

average versus a shorter term limit must be made on a case by 

case basis. Various factors weigh in favor of allowing a long 

term rolling average, such as historically unpredictable 

variations in emissions. Other factors may weigh in favor of a 

shorter term limit, such as the inability to set interim limits 

during the first year. The permitting agency must make a 

determination as to what monitoring and averaging period is 

warranted for the particular source-category in light of how 

close the allowable emissions would be to the applicability 

threshold. 

F. Clearly Recognized Enforcement

Violations of limits imposed by the rule or general permit

that limit potential to emit constitute violations of major
source requirements. In other words, the source would be 

violating a ?synthetic minor” requirement which may result in the 

source being treated as a major source under Titles I and V. The 

1989 Federal Register Notice provides for separate enforcement 

and permitting treatment depending on whether the source 

subsequently chooses to become major or remain minor. Thus, 

violations of the rule or general permit or violation of the 

specific conditions of the rule or general permit subjects the 

source to potential enforcement under the Clean Air Act and state 

law. The operating permit rule states that notwithstanding the 

shield provisions of part 70, the source subject to a general 

permit may be subject to enforcement action for operating without 

a part 70 permit if the source is later determined not to qualify 

for the conditions and terms of the general permit. Moreover, 

violation of any of the conditions of the rule or general permit 

may result in a different determination of the source’s potential 

to emit and thus may subject the source to major source 

requirements and to enforcement action for failure to comply with 

major source requirements from the initial determination. 

Rule Requirements for State General Permit Programs

As discussed above, general permit programs must be

submitted to EPA for approval under SIP authority or under

section 112(l), or both, depending on its particular pollutant

application. SIP and 112(l) approval and rulemaking procedures

must be met, including public notice and comment. The specific

application of the enforceability principles for establishing

State SIP or §112(l) general permit programs require that the

rule establishing the program set out these principles as rule

requirements. In other words, these principles must be specific

rule requirements to be met by each general permit. 

The rule establishing the program must require that (1)

general permits apply to a specific and narrow category of

sources; (2) sources electing coverage under general permits,

where coverage is not mandatory, provide notice or reporting to

the permitting authority; (3) general permits provide specific

and technically accurate (verifiable) limits that restrict the

potential to emit; (4) general permits contain specific

compliance monitoring requirements; (5) limits in general permits

are established based on practicably enforceable averaging times;

and (6) violations of the permit are considered violations of the

State and federal requirements and may result in the source being

subject to major source requirements. 

In addition, since the rule establishing the program does

not provide the specific standards to be met by the source, each

general permit, but not each application under each general

permit, must be issued pursuant to public and EPA notice and
comment. The 1989 Federal Register notice covering

enforceability of operating permits requires that SIP operating

permit programs issue permits pursuant to public and EPA notice

and comment. Title V requires that permits, including general

permits, be issued subject to EPA objection.

Finally, sources remain liable for compliance with major

source requirements if the specific application of a general

permit to the source does not limit the source’s potential to

emit below major source or major modification thresholds. (The

limits provided in these mechanisms may actually limit the

potential to emit of sources but may not limit the potential to

emit for some sources to below the threshold necessary to avoid

major source requirements. For example, a general permit for

industrial boilers may in fact provide limits that are sufficient

to bring a source with only two or three boilers to below the

subject thresholds, but a source with more than three boilers may

have a limited PTE but not limited below the major source

threshold.) Also, where the source is required to use another

mechanism to limit potential to emit, i.e., a construction

permit, the general permit may not be relied upon by the source

or the State to limit potential to emit.

Permits issued pursuant to the approved program, meeting the

above requirements, are adequate to provide federally enforceable

limits on potential to emit for New Source Review, title V, and

section 112 programs as long as they are approved pursuant to SIP

(section 110) and section 112(l) authorities.
Attachment 5

Example Language for Affirming Limits

[Note: the following language is taken from the Thursday

December 17, 1992 Federal Register, page 59931. To place this

excerpt into context, readers are encouraged to obtain the entire

Federal Register notice]

"The USEPA today finds the existing Illinois SIP regulations

to be consistent with federal requirements. If the State

followed its own procedures, each permit issued under this

regulation was subject to public notice and prior USEPA

review. Therefore, USEPA will consider all operating

permits issued which were processed in a manner consistent

with both the State regulations and the five criteria to be

federally enforceable with the promulgation of this rule

provided that any permits that the State wishes to make

federally enforceable are submitted to USEPA and accompanied

by documentation that the procedures approved today have

been followed. USEPA will expeditiously review any

individual permits so submitted to ensure their conformity

to the program requirements."