The facility used anhydrous ammonia, and extremely hazardous substance - subjecting them to the Clean Air Act General Duty Clause requirements. The facility failed to identify hazards which may result from such releases using appropriate hazard assessment techniques; failure to design and maintain a safe facility taking such steps as are necessary to prevent releases in violation of section 112(r) of the CAA, 42 U.S.C. ? 7412(r)(1), at the AMPI facility in Hoven, South Dakota.