Unexpected releases of highly hazardous chemicals can occur at businesses of any size. Many agricultural businesses handle chemicals such as anhydrous ammonia, aqua ammonia and nitric acid. These common fertilizers, and other chemicals can pose a risk to the employees, contractors and others on-site if an accidental release were to occur.

Congress passed amendments to the Clean Air Act in 1990. Their action required the Occupational Safety and Health Administration (OSHA) to develop regulations to help prevent the accidental release of highly hazardous chemicals that could pose a threat to employees.

OSHA established a list of more than 130 specific toxic and reactive chemicals and also includes flammable liquids and gases. The Process Safety Management standard was issued on February 24, 1992.