June 3, 1998
Robert Hodanbosi, Chief
Division of Air Pollution Control
Ohio Environmental Protection Agency
1800 WaterMark Drive
Columbus, Ohio 43215
Dear Mr. Hodanbosi:
I am writing to express our concerns about the periodic monitoring requirements in utility Title V permits recently processed by your office. The Title V permits for two utilities, Conesville Power Plant (Conesville) and Ohio Valley Electric Corporation, Kyger Creek Station (Kyger Creek), did not receive any comments from our agency during their draft or proposed stages and have been finalized. However, concerns about certain terms in these permits have been brought up in light of the developing periodic monitoring guidance and out of concern for national consistency. The Title V permits for two other facilities, DP&L, Killen Generating Station (Killen) and Department of Public Utilities in the City of Orrville, Ohio (Orrville), did receive comments from our office during their draft stage and have not yet reached the proposed stage.
Section 70.6(a)(3)(B) requires each Title V permit to contain periodic monitoring sufficient to yield reliable data from the relevant time period that are representative of the source’s compliance with the permit, if the underlying applicable requirements do not otherwise specify such monitoring. In order to meet this "gap-filling" provision, the periodic monitoring terms for each emission unit in the permit must include not only the appropriate method for monitoring, but also the minimum frequency at which the monitoring must be done in order to yield sufficient data to represent the source’s compliance with the permit. If a Title V permit’s monitoring requirements do not specify a frequency, the monitoring methods they institute cannot be considered periodic.
The four Title V permits require Part 60 Method 9 testing for many of the emission units, but they do not specify the frequency at which Method 9 must be performed. The Ohio Environmental Protection Agency (OEPA) has argued that the frequency does not need to be specified because the emission units either have 1) continuous opacity monitoring systems (COMS) which will provide monitoring data for direct compliance with opacity limits, or 2) inherently clean emissions and infrequent periods of operation. In accordance with our November 10, 1997 letter to you, the United States Environmental Protection Agency (USEPA) believes that such explanations belong in a statement of basis for each permit. We understand that OEPA is working on including statements of basis in future Title V permits. USEPA also believes that, regardless of operating history, the emission units for which COMS data is not required must have a frequency for Method 9 testing specified in the permits in order to meet the gap-filling requirement. USEPA recommends that OEPA consider the guidance written by Region 7 on periodic monitoring for opacity and the periodic monitoring guidance being developed by the Office of Air Quality Planning and Standards at USEPA.
USEPA has commented that OEPA’s utility permits appear to lack adequate requirements for periodic monitoring of particulate emissions, and for proper operation and maintenance of particulate control equipment. OEPA has explained that the actual particulate emissions will be well below the allowable limits, that the emissions will be parametrically monitored through the COMS, and that the COMS will provide adequate information to ensure proper operation and maintenance of control equipment. USEPA believes that these justifications, as well as a technical explanation of the correlation between COMS data and particulate matter emission limit compliance, also belong in a statement of basis for each permit.
The four permits allow the sources to be deemed in compliance if less than 1.5% of their nonexempt 6-minute average opacity values during a calendar quarter exceed the 20% opacity limit. USEPA has commented that this appears to be an unnecessary limit on enforcement authority. OEPA has argued that the 1.5% leeway is considered necessary based on experience in enforcing the 20% standard and on the Pacific Environmental Services study of continuous emission data, and that the COMS data will still be used for direct compliance. USEPA understands the need to practice enforcement discretion, but opposes putting such discretion in writing in any air pollution permit. USEPA will object to the incorporation of enforcement discretion in the federally enforceable section of proposed Title V permits, and requests that the Conesville and Kyger Creek permits be administratively amended to correct this problem as soon as possible.
Finally, the four utility permits contain a clause that contradicts the Credible Evidence rule. The permits state that in case of a discrepancy between COMS data and Method 9 data for a particular emission unit, the Method 9 data will take precedence. USEPA believes that the Credible Evidence rule prohibits preferring one monitoring method over another by default in a permit, and will object to any proposed Title V permit that contains such anti-credible evidence language. USEPA requests that the Conesville and Kyger Creek permits be administratively amended to correct this problem as soon as possible. USEPA understands that OEPA will be adding a Credible Evidence rule provision in the General Terms and Conditions section of their Title V permits, but does not believe this provision nullifies the problem of rejecting one type of possibly accurate monitoring data in favor of another.
In addition to making the administrative amendments to the Conesville and Kyger Creek permits prescribed above, we request that OEPA revise the Killen and Orrville permits to correct the problems mentioned in this letter before those permits reach the proposed stage. We also recommend that OEPA examine all other Title V permits for similar language and correct them appropriately.
We appreciate OEPA’s consideration of our comments and efforts to improve the periodic monitoring requirements in their Title V permits. If you have any questions regarding this letter, please contact Kaushal Gupta, of my staff, at (312) 886-6803.
Cheryl Newton, Chief
Permits and Grants Section (IL/IN/OH)