The EPA Did Not Ensure that Two of the Largest Air Oversight Agencies Identified and Inspected Potentially Significant Sources of Air Pollution

The Clean Air Act requires delegated agencies to work with the EPA to reduce air pollution from stationary sources. From at least 2006, the EPA did not ensure that two large, delegated agencies, the Texas Commission on Environmental Quality, or the TCEQ, and California's South Coast Air Quality Management District, identified a subset of synthetic-minor sources of air pollution, or SM-80s. The permit limitations on SM-80s need to be clear and enforceable because, if the limitations are not adhered to, the source may operate at major source levels and should be subject to more stringent requirements. The EPA's Office of Enforcement and Compliance Assurance's lack of in-depth evaluations of Regions 6 and 9, lack of SM-80 requirements, and reliance on unenforceable guidance contributed to deficiencies we identified in the regional offices' oversight.