An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »


Mercury and Air Toxics Standards (MATS) Administrative Compliance Orders

On May 21, 2019, the EPA’s Office of Enforcement and Compliance Assurance, through the Air Enforcement Division, Office of Civil Enforcement, issued four administrative compliance orders on consent (Orders) to the following owners/operators of coal refuse-burning electric generating units in the states of West Virginia and Pennsylvania: American Bituminous Power Partners, L.P. (Grant Town Facility), Inter-Power/AhlCon Partners L.P. (Colver Power Project), Northern Star Generation, LLC (Cambria CoGeneration Company) and Ebensburg Power Company (Ebensburg Power). The Orders address non-compliance with the acid gas provisions of the Mercury and Air Toxics Standard (MATS), found at 40 C.F.R. Part 63, Subpart UUUUU. Although the recipients of the Orders report compliance with the mercury limits under MATS, they are currently not in compliance with the acid gas emission standards for hydrochloric acid (HCl), which are evaluated for these units using sulfur dioxide (SO2) emissions as a surrogate for HCl. The standards applicable to these eastern bituminous coal refuse-fired units are currently under review by EPA prior to finalization in a final rule. The Orders establish enforceable SO2 emission limits for each unit and require that each unit come into compliance with MATS no later than April 15, 2020.    

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.