UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON. D.C. 20460 

JAN 25 1995 

OFFICE OF 

ENFORCEMENT AND 

COMPLIANCE ASSURANCE 

SUBJECT: Guidance an 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 and, 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 guidance describe, there are several

mechanisms available for sources to limit potential to emit. EPA

guidance have also describe the importance of practical

enforceability or the means used to limit the Potential to Emit.

This guidance is intended to provide additional guidance on

practical enforceability for such limits. We provide references

for guidance an 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" rules). 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 Base 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.

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

phrase is a less ambiguous description of the overall purpose of

these rules.
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 in 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 reffering to Title I State OperatingPermit

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,

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 source category 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 practical matter in order to be considered federally

enforceable. A source that violates this type of rule limiting

potential to emit below major a 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, 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

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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 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 most both legal and

practical federal enforceable 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

sources 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(1), the hazardous air pollutant program authority. This

mechanism allows permitting authorities to issue and revise

general permits consistent with SIP or 112(1) program

requirements without going through the SIP or 112(1) 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 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 or general permits may be readily developed

with the assistance of interested industry groups.

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The state general permit approach may allow sources to meet the

federal 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(1)

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,” form

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

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

1992; “Policy Determination an 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 (1997 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, record keeping requirements must be specified,

and equivalency provisions must meet certain requirements.

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Based an 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, record keeping 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) "arid (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 the 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 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

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 record keeping) 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

6
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 record keeping.” 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 record keeping

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

requirement’s 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.

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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 wall 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,

record keeping requirements, reporting requirements, and test

methods as appropriate for each potential to emit limitation; and

clarity which methods are used for making a direct determination

of compliance with the potential to emit limitations.

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

including continuous emission or opacity monitoring, and

measurements of various of Parameters of process or control

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

keeping of parameters that been limited ,such as hours of

operation, production levels, or raw material usage. Without a

verifiable plantwide, verifiable emission limits must assigned to

each unit or group of units subject to the subject to he 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 must the

monitoring must be sufficient to yield data form 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 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

emissions. Other factors may weigh in favor of 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

9
and permitting treatment depending on whether the source

subsequently chooses to become a 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 not withstanding 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 

or 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 requirements and

to enforcement action for failure to comply with major source

requirements from the initial determination.

G. 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(1), or both, depending on its particular pollutant

application. SIP and §112(1) 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(1) 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 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 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.

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Finally, sources remain liable or 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 

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

(section 110) and section 112(1) authorities.

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