Vegetable packing shed hit by anhydrous ammonia explosion in AZ
December 4, 2011
Two people were severely injured while working at a vegetable packing shed when they were exposed to an anhydrous ammonia explosion at Yuma (AZ) Express Cooling. The explosion sent a shock wave from between two tanks, sending one man running out about ten feet in front of the shock wave and another behind him who was engulfed in the shock wave that, to a witness, picked him up off the ground for about five or six feet, until he finally hit the ground running again.
The plume of ammonia smoke was about 45 feet high. People who were evacuating a nearby building ran right into it when they exited. When the alarms started, people ran out all the exits, but they didn't know what they were getting into. The wind carried the wave toward the southeast where everybody was evacuating so they were actually running into the plume of ammonia. The first YFD units to arrive on scene found multiple victims with varied degrees of ammonia exposure. The most severe exposure victim was transported immediately to Yuma Regional Medical Center by a YFD Rescue truck.
Exposure to anhydrous ammonia is extremely dangerous, and large doses can be fatal. According to the Agency for Toxic Substances and Disease Registry, ammonia is highly irritating to the eyes and respiratory tract, and can cause swelling and narrowing of the throat and bronchi, coughing, and an accumulation of fluid in the lungs. Prolonged skin contact can cause pain and corrosive injury. Exposure to concentrated vapor or solution can cause pain, inflammation, blisters, necrosis and deep penetrating burns, especially on moist skin areas. Skin contact with compressed, liquid ammonia, which is stored at –28ºF, causes frostbite injury and may also result in severe burns with deep ulcerations.
After the first victim was transported to YRMC, YFD personnel, working in cooperation with Rural Metro ambulance personnel, evaluated patients and readied them for transport. Eleven additional patients were transported to YRMC. Two, including the first victim transported by YFD, were flown out to medical facilities in Phoenix. Three YFD and four Rural Metro personnel were also decontaminated and evaluated for exposure to ammonia.
Yuma Police Department personnel blocked off traffic that remained blocked for approximately two hours. As emergency medical operations were underway, YFD hazardous materials technicians and Yuma Express Cooling employees confirmed the leak had been stopped and took additional actions to stabilize the situation.
The leak was believed to have been caused by a failure of a connection to a condensing coil on a cooling tower, YFD said. The incident is under investigation.