June 3, 1996





Mr. Robert F. Hodanbosi, Chief
Division of Air Pollution Control
State of Ohio Environmental Protection Agency
1800 Watermark Drive
Columbus, Ohio  49215-1099

Dear Mr. Hodanbosi:

     This letter is written in response to your letter of May 2,
1996 regarding: (1) the role of the U.S. Environmental Protection
Agency (U.S. EPA) in enforcement of state-only permit terms or
conditions and information collected related to those state-only
regulations in light of recent developments of the credible
evidence rulemaking; and (2) the U.S. EPA position pertaining to
the periodic monitoring requirements in part 70 and the soon to
be proposed compliance assurance monitoring (CAM) rule.  We have
coordinated a response to these questions with the Office of
Enforcement and Compliance Assurance who is responsible for
finalizing the credible evidence rulemaking and our Office of
General Counsel.

     As you noted, the U.S. EPA is considering promulgating
changes to part 51, 52, 60, and 61 to allow the use of
information other than that provided through compliance testing
in determining compliance with emission limitations or standards. 
You asked specifically whether the U.S. EPA intends to utilize
the information, required through operating permits to fulfill
state-only requirements as credible evidence in Federal
enforcement actions.  You feared that a decision to do so would
detrimentally affect the permitting process and potentially
result in inconsistencies on a national level.

     In proposing the changes to Parts 51, 52, 60, and 61, the
U.S. EPA's intent is to ensure that artificial or unnecessary
limitations on the use of otherwise credible evidence are
avoided, so that the trier of fact can consider all relevant
evidence admissible under the rules of the court.  To the extent
that data gathered in state-only required monitoring is probative
of violation of a federally enforceable emission standard, we
believe that such data would be admissible in federal court. 
Thus, it is possible that the U.S. EPA could use state-only
required monitoring in federal enforcement proceedings, in those
circumstances where data from such monitoring would be
sufficiently comparable to federally specified or approved
compliance data so as to make the state data credible evidence of
noncompliance with the standard.

     As a practical matter, U.S. EPA believes that the data which
source owners will be required to generate to monitor compliance
with the applicable requirements in their Title V permits,
including data from well-designed CAM plans, will generally
constitute most, if not all, of the credible evidence upon which
a federal enforcement action would be based.  Thus, if there are
state-imposed monitoring requirements that relate directly to
federal emission limitations, those requirements would naturally
form a necessary and useful basis for the source's CAM plan.  
Where such monitoring is unrelated to federal emission limits,
the practical effect of the monitoring on federal enforcement
will be negligible, particularly after the CAM rulemaking becomes
final.  By requiring all Title V permits to include additional
monitoring where necessary to assure compliance with federal
applicable requirements, the CAM rulemaking will help establish a
more level playing field across the nation regarding monitoring
requirements.

     Your second question had to do with the interpretation of
the current part 70 periodic monitoring requirements with regards
to permit applications now being submitted and the draft CAM
rule.  The Office of Air Quality Planning and Standards (OAQPS) 
believes appropriate selection of periodic monitoring for permits
is an issue to be resolved between source owners/operators and
the permitting authorities as part of the permit issuance
process.  The OAQPS does not intend to issue guidance on selection of periodic monitoring.  The CAM rule, when final, will
address both periodic monitoring and the enhanced monitoring
requirements as specified in the Clean Air Act.

     I appreciate the opportunity to be of service and trust that
this information will be useful to you.

                              Sincerely,

                                  /s/      

                              John S. Seitz
                                Director
                      Office of Air Quality Planning 
                              and Standards

cc:  Jonathan Fleuchaus, U.S. EPA, OGC (2333R)
     Bill Hunt, U.S. EPA, OAQPS (MD-14)
     David Kee, U.S. EPA, Region V, ARD (A18J)
     Jeanne M. Mallett, Ohio EPA, Supervising Attorney
     Jim Orlemann, Ohio EPA, DAPC
     Barrett Parker, U.S. EPA, OAQPS (MD-12)
     Tom Rigo, Ohio EPA, DAPC
     Adan Schwartz, U.S. EPA, OGC (2344)
     Michael Trutna, U.S. EPA, OAQPS (MD-12)
     Steven Viggiani, U.S. EPA, OECA (2242A)
     Lydia Wegman, U.S. EPA, OAQPS (MD-10)
     Peter Westlin, U.S. EPA, OAQPS (MD-19)