Anhydrous ammonia is widely used as refrigerant in many industrial facilities.
Ammonia is considered a high health hazard because it is corrosive to the skin, eyes, and lungs.
Prolonged contact at concentrations greater than 300 ppm can cause permanent injury or death. Accidental releases of ammonia from refrigeration facilities have resulted in both injuries and deaths to employees of these facilities. These have come from contact with both liquid and vapor forms of ammonia. Because refrigeration systems operate at elevated pressures, additional care must be taken to maintain and operate these systems so as to prevent releases with potentially catastrophic consequences. OSHA has developed this page to assist employers in identifying and controlling the hazards associated with the operation and maintenance of ammonia refrigeration systems.