Amerigas Corporation Poisonous Gas Leak Tank On Semitrailer

ntsb.gov, Jan 27, 2006

At 7:17 a.m., on August 22, 2003, an Amerigas Corporation (Amerigas) cargo tank semitrailer arrived at the AK Steel Corporation (AK Steel) facility in Middletown, Ohio. The driver pulled the vehicle up to the fill location and helped an AK Steel employee hook up to the fittings for a plant storage tank. According to the driver, about 7:40 a.m., the AK Steel employee began transferring anhydrous ammonia, a poisonous and corrosive gas, from the storage tank to the cargo tank. The driver said that it took about 30 minutes to equalize the pressure between the storage tank and the cargo tank. He said that once the pressure was equalized, the internal pressure in the cargo tank was 130 pounds per square inch gauge (psig).

About 8:20 a.m., while the cargo tank was still being loaded, its front head cracked open, releasing vapor. The driver, who had been resting in the tractor, got out and saw the escaping vapor. He said that he activated the emergency shut off device for the cargo tank and that according to the gauges, the cargo tank was a little less than half full, the internal pressure was about 170 psig, and the temperature of the anhydrous ammonia was 80 degrees F.

About 100 employees and contract workers were evacuated from the buildings downwind of the cargo tank and moved to safer locations. Five people were treated for inhalation injuries and released. The cost of repairing and replacing damaged equipment was about $25,000.