In a food processing facility, an employee moved a pallet from an upper storage rack using a forklift when the forks were lifted too high and contacted the roofing panel near an ammonia line. The roofing panel pushed up, bending the liquid ammonia refrigeration line. A two-bolt flange connection was strained, causing an uncontrolled leak past the sealing gaskets of the flange. The building was evacuated, and the leak released over 1,000 lbs. of ammonia into the building and atmosphere.
The building is a 110,000-square-foot industrial food processing facility built in 2000. The facility employs approximately 430 workers and comprises warehouses, food processing areas, and office spaces.
The facility has multiple areas for refrigerating or freezing food products and has a large refrigeration system containing approximately 8000 pounds of ammonia.
Ammonia concentrations of up to 4000 parts per million (ppm) were measured inside the building from personal sensors in the area of the piping damaged by emergency response personnel. The system leaked approximately 1100 pounds of ammonia indoors and into the atmosphere before the ammonia line was able to be isolated, and the leak stopped.