New air quality regulations, including the Cross-State Air Pollution Rule, have prompted substantial investments in emission control upgrades. But a series of additional standards—for mercury,...
Assuring Compliance With Air Emissions Limits
THE U.S. ENVIRONMENTAL PROTECTION AGENCY HAD A novel idea: For power plants and sources relying on devices to control air emissions, rather than attempt to monitor the actual physical emissions to determine compliance with federal law, it simply would require inspections and tests of the performance of the control device. %n1%n
This strategy was formalized in the EPA's compliance assurance monitoring (CAM) rule signed Oct. 17, 1997. The EPA's theory is that if the control device is working properly, it is likely pollutant emissions fall within the required limits. %n2%n
The CAM rule, added as part 64 to title 40 of the Code of Federal Regulations, forms one more part of the new Clean Air Act enforcement model envisioned by the 1990 amendments. Under CAM, air emissions sources would submit operating data that at least indirectly reflects the facility's compliance status on an ongoing basis. Taken with the relaxed standard for proof of violations and facility-specific permit requirements, a CAM-type rule should make federal enforcement easier.
Nevertheless, many questions arise regarding the formula that triggers the rule's application, plus its effectiveness and accuracy. Can utilities rely on equipment monitoring to produce trustworthy results? Will it actually become more difficult for utilities to certify that they meet emissions standards?
Other questions stem from the shift from reference tests to enforcement based upon any proffered credible evidence. This aspect has caused significant problems for industry.
All of the data from these tests will be available to EPA and citizens groups for evaluation. If their experts evaluate the data differently, and believe that it shows noncompliance, the source may be subject to enforcement based upon a "battle of the experts." Moreover, the CAM data may comprise only part of the data admitted into evidence by the reviewing court. Under the "credible evidence rule," a court is allowed to consider any credible evidence relevant to whether the source is in compliance. %n3%n Presumably, violation allegations could be proved though the CAM data is inconclusive. For instance, CAM reporting may show an excursion from the indicator ranges of its control device, but it may not confirm conclusively that a source is not in compliance.
Legislative History: In Search of a Fair Test
Prior to the 1990 amendments to the Clean Air Act, as a federal matter, major sources of air pollutants were not subject to monitoring, except when the source performed required tests. Between tests, sources were required to operate the equipment properly but were not required to monitor actual emissions. The assumption was that if the equipment tested within emissions limits and was operated properly, the emissions would remain within permitted limits.
Many states nevertheless imposed emissions monitoring requirements, often under the name "continuous emissions monitoring." Yet even if CEM data suggested a violation of the Act, the source was not subject to federal enforcement unless the data came from a required federal test. Since EPA could only detect violations by requesting a reference test, or after a source performed a scheduled test, the results were derived under controlled conditions that may not accurately represent typical