UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                     WASHINGTON, D.C. 20460



                                                  OFFICE OF
                                                  AIR AND RADIATION

MEMORANDUM

SUBJECT:  Automatic or Blanket Exemptions for ExcessEmissionsDuring
          Startup and Shutdowns Under PSD

FROM:     John B. Rasnic, Director
          Stationary Source Compliance Division
          Office of Air Quality Planning and Standards

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


     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 automatic exemptions
which allow excess emissions during startup and shutdown.  You also
requested that 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 shutdown
(especially as it pertains to Best Available Control Technology
(BACT) determinations) and on automatic exemptions that are granted
in PSD permits.  I understand that my staff has discussed this
issue and the response with your staff by phone.  However, we
regret the delay in providing 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
Implementation 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
contribute to violations of the national ambient air quality
standards.  This rationale applies to the PSD program not only
because PSD is ambient-based but also because generally, the PSD
program is part of the SIP.  Even in States where the PSD program
is not SIP approved, the emissions limits are established to
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 Edward E. 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 with Region 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 somewhat vague.  The exemptions
granted under some New Source Performance Standards (NSPS) are not
applicable to this issue under PSD.  The NSPS are technology based
standards that are not directly required for meeting ambient
standards.

     Likewise, we do not concur at this time with the approach as
outlined in the footnote.  You suggest setting a specific emission
rate that would apply during startup and/or shutdown that is
demonstrated to not cause a violation of any short-term increments
or standards.  While this may protect the ambient standards, this
cannot be easily determined 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 attachments to the memoranda provide that
infrequent periods of excess emissions during startup andshutdown
need not be treated as violations where the source adequately shows
that the excess could not have been prevented through careful
planning and design and that bypassing of control equipment was
unavoidable to prevent loss of life, personal injury, or severe
property damage.  Startup and shutdown of process equipment 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.  If excess emissions occur during routine startup and
shutdown due to a malfunction, then those instances should be
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