UNITEDSTATES ENVIRONMENTALPROTECTIONAGENCY WASHINGTON,D.C. 20460



## SEP

## 201999

MEMORANDUM SUBJECT: State Implementation Plans: Policy Regarding Excess Emissions During Malfunctions, Startup, and Shutdown

FROM:

Assistant Adminis

TO: Regional Administrators, Regions I

### - X

EPA's policy for state implementation plans (SIPs)regarding excess emissions during malfunctions, startup, shutdown, and maintenance is contained in memoranda from Kathleen Bennett, formerlyAssistant Administrator forAir, Noise and Radiation dated September 28, 1982and February 15, 1983. A recent review of SIPs suggests that several contain provisions that appear to be inconsistent with this policy, either because they were inadvertently approved after EPA issued the 1982-1983 guidance or because they were part of the SIP at that time and have never been removed. In order to address these provisions in a consistentmanner, today we are reaffirming and supplementing the 1982-83policy. In sodoing, we are taking this opportunity to clarify several issues of interpretation that have arisen since that time. The attached updated policy will clarify the types of excess emissions provisions statesmay incorporate into SIPs so that they can in turn provide greater certainty to the regulated community.

As EPA stated in its 1982memorandum, because excess emissionsmight aggravate air quality so as to prevent attainment or interfere with maintenance of the ambient air quality standards, EPA views all excess emissions as violations of the applicable emission limitation. Nevertheless, EPA recognizesthat imposition ofa penalty for sudden and unavoidable malfunctions caused by circumstances entirely beyond the control of the owner or operator may not be appropriate. Accordingly, a state or EPA can exercise its "enforcementdiscretion" to refrain from taking an enforcement action in these circumstances.

Themain question of interpretation that has arisen regarding the old policy is whether a statemay go beyond this "enforcement discretion" approach and include in its SIP a provision that would, in the context of an enforcement action for
excess emissions,.excuse a source frompenalties if the source
can demonstrate that it meets certain objective criteria (an "affirmative defense"). Thispolicy clarifies that states have the discretion to provide such a defense to actions for penalties brought for excess emissions that arise during certain malfunction, startup,and shutdown episodes.

In the context of malfunctions, EPA recognizes that even equipment that is properly designed and maintained can sometimes fail. At the same time, EPA has a fundamental responsibility under the Clean Air Act to ensure that SIPSprovide for attainment and maintenance of the national ambient air quality standards ("NAAQSU)andprotection of PSD increments. Thus, EPA cannot approve an affirmative defense provision that would undermine the fundamental requirement of attainment and maintenance of the NAAQS, or any other requirement of the Clean Air Act. See sections 110(a)and (1)of the Clean Air Act, 42 U.S.C. § 7410(a)and (1) .l Accordingly, an acceptable affirmative defense provision may only apply to actions for penalties, but not to actions for injunctive relief. This restriction insures that both state and federal authorities remain able toprotect air quality standardsand PSD increments.
Furthermore, this approach is appropriate only when the respective contributions of individual sources to pollutant concentrations in ambient air are such that no single source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments.' Where a single source or small

'pursuant to Section 110(1),EPAmay not approve a SIP revision if "therevision would interfere with any applicable requirement concerning attainment and reasonable further progress, or any other applicable requirement of this chapter." See also CAA 5 193, 42U.S.C. 5 7515,and the definitions of "emission limitation" and "emissionstandard"contained in CAA 5 302(k),42U.S.C.5 7602(k)



### . 

## ' In the case of lead and sulfurdioxide, attainment problems usually are caused by one or a few sources and angroup of sources has the potential to cause an exceedance of the NAAQS or PSD increments, EPA believes an affirmative defense approach will not be adequate toprotect public health and the environment,and the only appropriate means of dealing with
excess emissions duringmalfunction, startup, and shutdown episodes is through an enforcement discretion appr~ach.~

EPA is also taking this opportunity to clarify that it does not intend to approve SIP revisions that would recognize a state director's decision to bar EPAfsor citizens' ability to enforce applicable requirements. Such an approach would be inconsistent with the regulatory scheme established in Title I of the Clean Air Act. EPA is also adding contemporaneous record keeping and notification criteria tomake its policy regarding these types of events consistent with its enforcement approach.
Finally, EPA is clarifying how excess emissions that occur during periods of startup and shutdown should be addressed. In general, because excess emissions that occur during theseperiods
are reasonably foreseeable, they should not be excused. However, EPA recognizes that, for some source categories, even the best available emissions control systemsmight not be consistently effective during startup or shutdown periods. In areas where the respective contributions of individual sources topollutant concentrations in ambient air are such that no single source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments, these technological limitations may be addressed in the underlying standards themselves through narrowly-tailored SIP revisions that take into account the potential impacts on ambient air quality caused by the inclusion of these allowances. In these instances, as part of its justification of the SIP revision, the state should analyze the

affirmative defense is not appropriate. This situation canbe particularly aggravated where a short-termstandard (e.g.,where exceedances orviolations arebased ona fewhour period) is also inplace. Although this policy is generally applicable forother NAAQS, enforcement discretion is the only appropriate approach fordealing with excess emissionsduring startup, shutdown,and malfunction ina specific areawhere a single source or a small group of sources has thepotential to cause nonattainment of a short-termNAAQS.

3 InAmerican TruckingAssociation v. EPA, 175 

### F. 3d 1027 (D.C.Circ.,1999),the court remanded the PM2.5 NAAQS to the EPA. TheAgency has not determined whether thispolicy is appropriate for PM2.5 NAAQS.impact of the potential worst-case emissions that could occur during startup and sh~tdown.~

Inaddition to this approach, states may address thisproblem through the use of enforcement discretion or they may include a general affirmative defense provision in their SIPs for short and infrequent startup and shutdownperiods along the lines outlined in the attachment. As mentioned above, however, in those areas where a single source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments, issues relating to excess emissions arising during startup and shutdown may only be addressed thqough an enforcement discretion approach.

All Regions should review the SIPs for their states in light of this clarification and take steps to insure that excess emissions provisions in these SIPs are consistent with the attached guidance.

Attachment

4~tates may account for suchemissionsby including them in their routine rule effectiveness estimates. Rule effectiveness estimates may beprepared in accordance with an EPA policy document entitled "Guidelines for Estimating andApplying Rule Effectiveness forOzone/Carbon Monoxide State Implementation Plan Base Year ~nventories."(EPA-452/R-92-010) November 1992.

. . . . . .Attachment

POLICY ON EXCESS EMISSIONS DURING MALFUNCTIONS, STARTUP,AND SHUTDOWN Introduction

Thispolicy specifies when and inwhat manner state implementation plans (SIPS)may provide'for defenses to violations caused by periods of excess emissions due to 

### malfunction^,^ startup, or shutdown, Generally, since SIPSmust provide for attainment and maintenance of the national ambient air quality standards and the achievement of PSD increments, all periods of excess emissions must be considered violations. Accordingly, any provision that allows for an automatic exemption' for excess emissions isprohibited.

However, the imposition of a penalty for excess emissions during malfunctions caused by circumstances entirely beyond the control of the owner or operator may not be appropriate. States may, therefore, as an exercise of their inherent enforcement discretion, choose not topenalize a source that has produced excess emissions under such circumstances.

This policy provides an alternative approach to enforcement discretion for areas and pollutants where the respective contributions of individual sources topollutant concentrations in ambient air are such that no single source or small group of
sources has the potential to cause an exceedance of the NAAQS or PSD increments. Where a single source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments, as is often the case for sulfur dioxide and lead,3 EPA believes approaches other than enforcement discretion are not appropriate. In such cases, any excess emissions may have a significant chance of causing an exceedance or violation of the applicable standard or PSD increment.

1The term excess emissionmeans anair emission level which exceeds any applicable emission limitation. Malfunction means a sudden and unavoidable'breakdown ofprocess or control equipment. 

## he term automatic exemwtionmeans a generally applicable provision in a SIP that would provide that if certain conditions existed during a period of excess emissions, then those exceedances would not be considered violations.

3Thispolicy alsodoesnot apply forpurposes of PM2.5 NAAQS. InAmerican TruckingAssociation v. EPA, 175 F. 3d 1027

(D.C.Circ., 1999), the court remanded the PM2.5NAAQS to the EPA. TheAgency has not determined whether this policy is appropriate for PM2.5NAAQS.Except where 'asingle source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments, statesmay include in their SIPS affirmative defenses4for excess emissions, as long as the SIP establishes limitations consistent with those set out below. If approved into a SIP, an affirmative defense would be available to sources in an enforcement action seekingpenalties brought by the state, EPA, or citizens. However, a determination by the statenot to take an enforcement action would not bar EPA or citizen acti~n.~

Inaddition, in certain limited circumstances, itmay be appropriate for the state tobuild into a source-specific or source-category-specific emission standard a provision stating that the otherwise applicable emission limitations do not apply during narrowly defined star'tupand shutdown periods.

I. AUTOMATIC EXEMPTIONS AND ENFORCEMENT DISCRETION

If a SIP contains a provision addressing excess emissions, it cannot be the type that provides for automatic exemptions. Automatic exemptions might aggravate ambient air quality by excusing excess emissions that cause or contribute to a violation of an ambient air quality standard. Additional grounds for disapproving a SIP that includes the automatic exemption approach
are discussed inmore detail at 42 Fed. Reg. 58171 (November8, 1977) and 42 Fed. Reg. 21372 (April 27, 1977). As a result, EPA will not approve any SIP revisions that provide automatic exemptions for periods of excess emissions.

Thebest assurance that excess emissions will not interfere with NAAQS attainment, maintenance, or increments is to address
excess emissions through enforcement discretion. Thispolicy provides alternative means for addressing excess emissions of criteriapollutants. However, this policy does not apply where a single source or small group of sources has the potential to
cause an exceedance of the NAAQS or PSD increments. Moreover,

4The term affirmative defense means, in the context of an enforcement proceeding, a response ordefenseput forward by a defendant, regardingwhich the defendant has the burden ofproof, and themerits of which are independently and objectively evaluated ina judicial oradministrative proceeding.

'~ecauseall periods of excess emissions areviolations and because affirmative defense provisionsmay not apply inactions for injunctive relief,under no circumstances would EPA consider periods of excess emissions, even if covered by an affirmative defense, tobe "federallypermitted releases" under EPCRA or CERCLA.nothing in this guidance should be construed as requiring states to include affirmative defense provisions in their SIPS.

11. AFFIRMATIVE DEFENSES FORMALFUNCTIONS

EPA can approve a SIP revision that creates an affirmative defense to claims for penalties in enforcement actions regarding
excess emissions caused by malfunctions as long as the defense does not apply to SIPprovisions that derive from federally promulgated performance standards or emission limits, such as new sourceperformance standards (NSPS)and national emissions standards for hazardous air pollutants (NESHAPS).6 In addition, affirmative defenses are not appropriate for areas and pollutants where a single source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments. Furthermore, affirmative defenses to claims for injunctive relief are not allowed. Tobe approved, an affirmative defense provisionmust provide that the defendant has the burden of proof of demonstrating that:

1. The excess emissions were caused by a sudden, unavoidable breakdown of techno10$~,beyond the control of the
owner or operator;



### 2. The excess emissions (a)did not stem from any activity
or event that could have been foreseen and avoided, or planned for, and (b)could not have been avoided by better operation and maintenance practices;

3. To the maximum extent practicable the air pollution control equipment or processes were maintained and operated in a
manner consistent with good practice forminimizing emissions;

4. Repairs were made in an expeditious fashion when the operator knew or shouldhave known that applicable emission limitations were being exceeded. Off-shift labor and overtime must have been utilized, to the extent practicable, to ensure that such repairs were made as expeditiously as practicable;



### 5. The amount and duration of the.excessemissions (includingany bypass) were minimized to the maximum extent practicable during periods of such emissions;



### 90the extent a state includesNSPS orNESHAPS in its SIP, the standards should not deviate from those that were federally promulgated. Because EPA set these standards taking into account technological limitations,additional exemptions would be inappropriate.6. All possible stepswere taken tominimize the impact of the excess emissions on ambient air quality;

7. All emission monitoring systems were kept in operation if at all possible;



### 8. The owner or operator's actions in response to the
excess emissions were documented by properly signed, contemporaneous operating logs, or other relevant evidence;

9. The excess emissionswere not part of a recurring pattern indicative of inadequate design, operation, or maintenance; and

10. The owner or operator properly and promptly notified the appropriate regulatory authority.

EPA interpreFs these criteria narrowly. Only those malfunctions that are sudden, unavoidable, and unpredictable in nature qualify for the defense. For example, a single instance of a burst pipe that meets the above criteriamay qualify under an affirmative defense. Thedefense would not be available, however, if the facilityhad a history of similar failures because of improper design, improper maintenance, orpoor operating practices. Furthermore, a sourcemust have taken all availablemeasures to compensate for and resolve themalfunction. If a facility has a baghouse fire that leads to excess emissions, the affirmative defense would be appropriate only for the period of time necessary tomodify or curtail operations to come into compliance. The fire should not be used to excuse excess emissions generated during an extended period of time while the operator orders and installs new bags, and relevant SIP language must limit applicability of the affirmative defense accordingly.

111. EXCESS EMISSIONS DURING STARTUPAND SHUTDOWN
In general, startup and shutdown of proc-essequipment are part of the normal operation of a source and should be accounted for in the planning, design, and implementation of operating procedures for the process and control equipment. Accordingly, it is reasonable to expect that careful and prudent planning and design will eliminate violations of emission limitations during such periods.

A. SOURCE CATEGORY SPECIFIC RULES FOR STARTUP AND SHUTDOWN

For some source categories, given the types of control technologies available, there may exist short periods of emissions during startup and shutdown when, despitebest efforts regarding planning, design, and operating procedures, theotherwise applicable emission limitation cannot be met. Accordingly, except in the case where a single source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments, it may be appropriate, in consultation with EPA, to create narrowly-tailored SIP revisions that take these technological limitations into account and state that the otherwise applicable emissions limitations donot apply during narrowly defined startup and shutdown periods. Tobe approved, these revisions should meet the following requirements:



### 1. The revision must be limited to specific,narrowlydefined source categories using specific control strategies

(e-g.,cogeneration facilities burning natural gas .andusing selective catalytic reduction);



### 2. Use of the control strategy for this source category must be technically infeasible during startup or shutdown periods;

3. The frequency and duration of operation in startup or shutdown mode must be minimized to the maximum extent practicable;

4. As part of its justification of the SIP revision, the state should analyze the potential worst-case emissions that could occur during startup and shutdown;



### 5. All possible stepsmust be taken tominimize the impact of emissions during startup and shutdown on ambient air quality;

6. At all times, the facility must be operated in a manner consistent with good practice forminimizing emissions, and the
sourcemust have used best efforts regarding planning, design, and operating procedures tomeet the otherwise applicable emission limitation; and

7. The owner or operator's actions during startup and shutdown periods must be documented by properly signed, contemporaneous operating logs, or other relevant evidence.



### B. GENERAL AFFIRMATIVE DEFENSE PROVISIONS RELATING TO STARTUP AND SHUTDOWN

In addition to the approach outlined in Section II(A) above, states may address the problem of excess emissions occurring during startup and shutdown periods through an enforcement discretion approach. Further, except in the case where a single
source or small group of sources has the potential to cause an exceedance of the NAAQS or PSD increments, states may also adopt for their SIPS an affirmative defense approach. Using thisapproach, all periods of excess emissions arising during startup and shutdownmust be treated as violations, and the affirmative defenseprovision must not be available for claims for injunctive relief. Furthermore, tobe approved, such a provision must provide that the defendant has the burden of proof of demonstrating that:



### 1. Theperiods of excess emissions that occurred during startupand shutdown were short and infrequent and could not have been prevented through careful planning and design;

2. The excess emissionswere not part of a recurring pattern indicative of inadequate design, operation, or maintenance;



### 3. If the excess emissions were caused by a bypass (an intentional diversion of control equipment), then the bypass was unavoidable toprevent loss of life,personal injury, or severe property damage;

4. At all times, the facility was operated in amanner consistent with good practice for minimizing emissions;



### 5. The frequency and duration of operation in startup or shutdownmode was minimized to the maximum extent practicable;



### 6. All possible stepswere taken tominimize the impact of the excess emissions on ambient air quality;

7. All emission monitoring systems were kept in operation if at all possible;



### 8. The owner or operator's actions during theperiod of
excess emissionswere documented by properly signed, contemporanecus operating logs, or other relevant evidence; and

9. The owner or operator properly andpromptly notified the appropriate regulatory authority.

Ifexcess emissions occur during routine startup or shutdown periods due to amalfunction, then those instances should be treated as othermalfunctions that are subject to themalfunction provisions of thispolicy. (Reference Part I above).