UNITEDSTATESENVIRONMENTALPROTECTION'AGENCY WASHINGTON,D.C. 20400



### JAN

## 2 81993

OFFICEOF AIRANDRAOIATlON

MEMORANDUM

SUBJECT: Automatic or Blanket Exemptions for Excess Emissions During Startup'and Shutdowns Under

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FP.OM: John B. Rasnic,

# Direct~ Stationary Source**Compl~ance** Division Office of Air Quality Planning and Standards

TO: Linda M. Murphy, Director Air, Pesticides and Toxics Management Division Region :::

This is in response to your memorandum dated June 15, 1992, asking that we advise Region I on whether you are correct in telling States and applicants that Prevention of Significant Deterioration (PSD) permits,cannot contain**automat~c** exemptions which allow excess emissions during startup and shutdown. You also requested**~ha~** the Stationary Source Compliance Division (SSCD) issue a memo which outlines the Environmental Protection Agency's (EPA's) policy on excess emissions during startup and**sh~tdown** (especially as it per:tains to Best Available Control**Tec~no~ogy** (BACT) determinations) and on automatic exemptions that

are**gran~ed** in PSD permits. I understand that my staff has discussed this issue and the tesponse with your staff by phone. However, we regret the delay inproviding a written response.

The two memoranda you mention, entitled "Policy on Excess Emissions During Startup, Shutdown, Maintenance, and Malfunction" from Kathleen M. Bennett (dated February 15, 1983 and September 28, 1982), address automatic exemptions under the State Imp'lementation Plan (SIP). The memoranda state that the rationale for establishing these emissions as violations, as opposed to granting automatic exemptions, is that SIPs are ambient-based standards and any emissions above the allowable may cause or

,ntribute to violations of the national ambient air quality

andards. This rationale applies to the PSD programnot only

ecause PSD is ambient-basedbut alsobecause generally, the PSD
rogram ispart of the SIP. Even in States where the PSD program is not SIP approved, the emissions limits are establishedto protect increments and the national ambient air quality standards (NAAQS)

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Another 1977 memorandum, entitled "Contingency Plan for FGD Systems During Downtime as a Function of PSD" from EdwardE. Reich, states that PSD and SIP regulations require the establishment of emission'limitations which will be sufficient to

ensure nondegradation of air quality and attainment and maintenance,of the NAAQS. This memorandum specifically refers to the April 27, 1977 Federal Register notice (42 FR 21472) that is also mentioned in the EPA policy attached to the Bennett memoranda.

Although we concur withRegion I that PSD permits cannot contain automatic exemptions which allow excess emissions during startup and shutdown, we do not believe,that EPA's policy concerning this issue under PSD is some,what vague. The exemptions gr.anted under some New SourcePerformance Standards (NSPS) are not applicable to this issue under PSD. The NSPS are technologybased standards that arenot directly required for meeting ambient standards.

Likewise, we do not concur at this time with the approach as outlined in the**foo~note.** You suggest setting a specific emission
rate that would apply during startup and/or shutdown that is demonstratedto not cause a violation of any short-term increments

or standards. While this may protect the ambient standards, this
cannot be easily de=ermined if, as is suggested, the emission rate would reflect a longer averaging time. Further, as the 1982 memoranda states, without clear definition and limitations, these automatic exemptions or even secondary limits could effectively shield excess emissions arising from poor operation and maintenance or design, thus precluding attainment.

However, the States retain enforcement discretion, as discussed in the memoranda; to address the.occurrence of excess emissions. The**at~achments** tothe memoranda provide that infrequent periods of excess emissions during startup and shutdown need not be treated as violations where the source·adequately 'shows that the excess could not have been preventedthrough

careful planningand design and that bypassing of control equipment was unavoidable to prevent loss of life, personal injury, or severeproperty damage. Startup and shutdown of
process equipment are part,ofthe normal operation ofa source and shouldbe accounted for in theplanning, design and implementation of operatingprocedures 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. If excess emissions occur during routine startup and shutdown que to a malfunction, then those instances shouldbe treated as other malfunctions which are subject to the malfunction provisions of the policy (attached)

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If you have any questions regarding this matter, please
contact Clara Poffenberger at 703 308-8709.

Attachments