EPA Executes Administrative Compliance Order to Imperial Zinc, Corp., Chicago, Illinois: EPA is executing an Administrative Compliance Order (ACO) under the Clean Air Act to Imperial Zinc Corp. (Imperial Zinc) for violating the National Emission Standards for Hazardous Air Pollutants for Secondary Nonferrous Metals Processing Area Sources (NESHAP Subpart TTTTTT) and Illinois State Implementation Plan permitting requirements. The ACO requires Imperial Zinc to operate its capture and control system consistent with a December 2015 performance test, submit and operate in accordance with an operating and maintenance plan and re-submit a site-specific monitoring plan for a recently installed bag leak detection system (BLDS), maintain records of BLDS and baghouse performance, and submit a permit application for a construction permit and operating permit to Illinois Environmental Protection Agency incorporating the requirements of the ACO.