OSHA has cited Amtec Corp., a contractor at the U.S. Army's Space & Missile Defense Command, Redstone Arsenal, in Huntsville for safety violations following an explosion that killed two workers, according to an agency press release.

In May, two workers were killed after suffering third-degree burns over 90 percent of their bodies as a result of an explosion involving ammonium perchlorate and n-Butanol. The workers were attempting to purify the ammonium perchlorate by removing it from a mixture that also contained n-Butanol. A decanter centrifuge separated the ammonium perchlorate and n-Butanol mixture. During the separation process, an explosion occurred.

"Management knew the hazards associated with ammonium perchlorate recovery and failed to ensure the proper equipment was being used, while also allowing the workers to process the material in excess of 10 times the amount of explosives according to the Army's standard operating procedures," said Roberto Sanchez, OSHA's area director in Birmingham, Ala.

The company is being cited with two willful violations for allegedly exposing workers to fire and explosive hazards by not verifying the suitability of the equipment being used to process ammonium perchlorate and n-Butanol slurry and for operating the system adjacent to a decanter centrifuge instead of in a remote location. OSHA defines a willful violation as one committed with plain indifference to or intentional disregard for employee safety and health.

Four serious citations are also proposed for hazards related to dispensing n-Butanol to containers without bonding between the containers or the building's grounding system, storing more than 120 gallons of n-Butanol in an area where the ammonium perchlorate recovery process was being conducted, allowing sources of ignition in a location where flammable vapors could accumulate and failing to provide flame retardant clothing for each worker. A serious citation is issued when there is substantial probability that death or serious physical harm could result from a hazard about which the employer knew or should have known.

OSHA has proposed a total of $134,400 in penalties against the company, which has 15 business days from receipt of the citations and proposed penalties to comply, request an informal conference with OSHA's area director or contest the findings before the independent Occupational Safety and Health Review Commission.