This is another incident involving hot-gas defrost and liquid hammering effect causing a large diameter pipe to fail and releasing 183 pounds of NH3. This failure actually occurred inside the building (vs the 2010 Mobile, AL hammering release occurred on the roof of the building) and had far-reaching and serious consequences.
Respondent owns and operates the poultry processing facility which includes various equipment and processes associated with food preparation, packaging, and transportation. At the Facility, the Respondent utilizes a refrigeration system to ensure processed food is maintained at safe temperature prior to, and during, shipment. The refrigeration system uses anhydrous ammonia as a coolant. Emissions of regulated substances or other extremely hazardous substances are possible from the Facility or the equipment located therein. The refrigeration system at the Facility is a single process with more than 10,000 pounds of anhydrous ammonia making it a covered process subject to the requirements of 112(r)(7) of the Clean Air Act and the implementing regulations at 40 C.F.R. Part 68. On April 22, 2016, maintenance work was performed at the Facility. Specifically, a maintenance worker replaced a belt on a spiral freezer. The worker utilized a written standard operating procedure (“SOP”) in performing the work. To safely perform the belt replacement maintenance the worker turned off the spiral freezer, which was in defrost mode at the time. The defrost cycle was interrupted when the freezer power was turned off. According to Respondent and the spiral freezer manufacturer, the spiral freezer requires routine and uninterrupted defrosting for proper performance.