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
operations. When the 1990 amendments were adopted, many were urging Congress to require CEM-type monitoring of actual emissions. %n4%n
EPA's CAM rule stands as a product of the 1990 amendment to section 114(a) of the Act that allowed EPA to require "enhanced monitoring" and "compliance certifications." The legislative history is not definitive, but appears to suggest that Congress intended that the EPA could require CEM, along with periodic compliance certification. The legislative history also includes a statement that the monitoring data and certifications could be used as evidence of a violation.
The CAM rule was thought necessary to solve the difficult problem of federal emissions enforcement. In general, the government could prove violations of the Clean Air Act only by carrying out a scheduled reference test already spelled out in the regulation defining the applicable emissions limit. The EPA would be obliged to call on the source to perform the test. Moreover, any such test performed under controlled conditions might not accurately depict typical operations.
This difficulty encountered in devising a fair test to enforce the Clean Air Act stands in marked contrast to enforcement practice under the Clean Water Act. Under the CWA, each discharger of wastewater into navigable waters is required to have a facility-specific permit with established discharge limits that are periodically monitored. The results are made public on "discharge monitoring reports." Under the CWA, the permittee self-monitors and self-reports violations of its permit. Facility operators are required to certify as to compliance with the permit restrictions. Enforcement is much easier than proving a violation by infrequently calling for the performance of an elaborate, highly detailed and well-controlled test.
In enacting the 1990 amendments to the Clean Air Act, argued some in the debate, Congress adopted the CWA enforcement model. %n5%n Air pollutant sources would be required to self-monitor actual emissions and self-report violations. Source operators would be required to certify the compliance status of the facility, just like for wastewater dischargers. Enforcement would prove faster, better and cheaper because proving violations would involve pointing to the source's own monitoring results. With this scheme in mind, the EPA chose first in 1993 to propose an "enhanced monitoring" rule that would have established that program. %n6%n
The reaction from industry was dramatic and negative. %n7%n Air emissions measurement and control was thought too complex and difficult for monitoring equipment results to identify a violation of the Act definitively. The EPA quickly withdrew the enhanced monitoring rule, and jettisoned the idea of continuous monitoring of actual emissions. In its place, EPA published the first of two proposed CAM rules. %n8%n
Rather than monitor and report actual emissions, the CAM proposals would require the monitoring and reporting of operations of the source's air pollution control equipment. Rather than report "deviations" from air permit limits (and, likely, demonstrate Act violations), the source would report "exceedances" of emissions limitations and "excursions" from the acceptable operating ranges of its pollution control equipment. Exceedances and excursions may identify equipment or operation problems that must be fixed, but they may not actually show Act violations. After several