Details

Parent Category: Safety Info Posts

Category: Chemical Process Safety (PSM/RMP)

Published: 11 July 2011

At 7:17 a.m., on August 22, 2003, a cargo tank semitrailer arrived at a facility. The driver pulled the vehicle up to the fill location and helped an employee hook up to the fittings for a plant storage tank. According to the driver, about 7:40 a.m., the 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.  Here are the details...

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