En-Chro Plating, Ltd. (En-Chro) owns and operates a plating facility that is an area source of hazardous air pollutant emissions at 2755 West Lake Street, Melrose Park, Illinois (the Facility), where it conducts industrial hard-chrome electroplating and nickel electroless plating. The U.S. Environmental Protection Agency conducted an inspection of the Facility on February 6, 2013 for, among other things, compliance with the National Emission Standards for Hazardous Air Pollutants: Area Source Standards for Plating and Polishing Operations at 40 C.F.R. Part 63, Subpart WWWWWW (Subpart WWWWWW). The Facility has one electroless-nickel plating tank subject to Subpart WWWWWW (identified by En-Chro as EN-1). In an email dated April 17, 2013, EPA requested that En-Chro submit the Initial Notification, Notification of Compliance Status, and all annual certification of compliance reports it prepared for Subpart WWWWWW for this tank. In response to EPA's April 17, 2013, email, En-Chro's environmental consultant indicated that En-Chro believed it was exempt from Subpart WWWWWW requirements and did not have the requested documents. To come into compliance, En-Chro will submit to EPA an Initial Notification and Notification of Compliance Status and prepare annual certifications of compliance reports in accordance with Subpart WWWWWW. En-Chro will also begin keeping the records required to show continuous compliance, and shall maintain continuous compliance, with each applicable mana