U.S. EPA Region 5 will enter into an Administrative Consent Order (ACO) with Valicor Environmental Services, LLC (Valicor), located in Dayton, Ohio to address violations of the National Emission Standards for Hazardous Air Pollutants from Off-Site Waste and Recovery Operations (NESHAP Subpart DD). Specifically, Valicor failed to address excess condensate in its regenerative thermal oxidizer (RTO), which led to an explosion that caused significant damage to ductwork connected to the RTO and resulted in excess emissions. Additionally, Valicor failed to properly enclose multiple tanks and containers and failed to properly maintain and operate emission monitoring equipment. The ACO requires Valicor to operate new condensation control equipment, continuously monitor and limit relative humidity in its capture and control system, submit an application to incorporate the limits into its Clean Air Act permits, and install additional control equipment if unable to consistently comply with the limits. The ACO also requires Valicor to incorporate instrumentation into inspections of its emission controls, conduct these inspections more frequently, and ensure that its technicians complete training on use of the instrumentation. The ACO will be issued concurrently with a Consent Agreement and Final Order (CAFO). The CAFO requires Valicor to pay a penalty of $140,000.