Response to Clean Air Act Section 126(b) Petitions From Delaware and Maryland

The Environmental Protection Agency (EPA) is denying four petitions submitted by the state of Delaware and one petition submitted by the state of Maryland under Clean Air Act (CAA or Act) section 126(b). The petitions were submitted between July and November 2016. Each of Delaware's four petitions requested that the EPA make a finding that emissions from individual sources in Pennsylvania or West Virginia are significantly contributing to Delaware's nonattainment of the 2008 and 2015 8-hour ozone national ambient air quality standards (NAAQS). Maryland's petition requested that the EPA make a finding that emissions from 36 electric generating units in Indiana, Kentucky, Ohio, Pennsylvania, and West Virginia are significantly contributing to ozone levels that exceed the 2008 8-hour ozone NAAQS in Maryland, and, therefore, are interfering with nonattainment and maintenance of the 2008 ozone NAAQS. The EPA is denying the petitions based on the best information available to the agency at this time, and particularly in light of an existing regulation already addressing emissions from these facilities: The Cross-State Air Pollution Rule Update for the 2008 ozone NAAQS (CSAPR Update). The EPA's denial finds that Delaware has not demonstrated that the named sources emit or would emit in violation of the CAA's ``good neighbor'' provision. Further, the agency's independent analysis indicates that the identified sources in Delaware's and Maryland's petitions do not currently emit and are not expected to emit pollution in violation of the good neighbor provision for either the 2008 or 2015 ozone NAAQS.