Respondent is the operator of a chemical manufacturing and distribution facility that ses anhydrous ammonia to produce several chemicals, including ammonium sulfate (made by reacting ammonia with sulfuric acid) and aqueous ammonia (a solution of anhydrous ammonia and water). Anhydrous ammonia arrives by railcar and is distributed through pipes to chemical processes around the Facility. Sulfuric acid tanks and a chemical warehouse are located at the southern end of the Facility. Multiple railcars of chemicals are placed on rail sidings at the Facility.