A large explosion and fire that took the lives of two workers at the Bayer CropScience plant in West Virginia last August was caused by a thermal runaway reaction during the production of an insecticide. The event likely resulted from significant lapses in chemical process safety management at the plant, U.S. Chemical Safety Board (CSB) investigators said.
The blast on Aug. 28, 2008 in Institute, West Virginia occurred as the runaway reaction created extremely high heat and pressure in a vessel known as a residue treater, which ruptured and flew about 50-feet through the air, demolishing process equipment, twisting steel beams, and breaking pipes and conduits. Two operators died as a result.
Eight workers reported symptoms of chemical exposure, including aches and intestinal and respiratory distress, including two employees of the Norfolk Southern railway company and five Tyler Mountain, West Virginia volunteer firefighters, and an Institute, West Virginia volunteer firefighter. Two sought treatment at a hospital emergency room the next day, were treated, and released.
Releasing the preliminary findings prior to a planned CSB public meeting in Institute, CSB Board Chairman John Bresland said the investigation is continuing.
“The explosion at Bayer was a very serious and tragic event that could have had additional grave consequences. There were significant lapses in the plant’s process safety management, including inadequate training on new equipment and the overriding of critical safety systems necessitated by the fact the unit had a heater that could not produce the required temperature for safe operation,” Bresland said.
Investigators found that the explosion occurred within 80 feet of a pressure vessel containing more than 13,000 pounds of methyl isocyanate, or MIC, a raw material for the pesticide the company was making at the time, and the same chemical that caused death and injury in an acciddent in Bhopal 25 years ago.
“As our investigation continues, we will look further into the issues surrounding the safe placement of the tank and its potential vulnerability. We note that other chemical companies, notably DuPont, no longer store MIC in their chemical production and we are looking into other systems that make and then immediately use the MIC, eliminating the need for storage,” Bresland said.
Bayer CropScience in Institute is a large chemical complex of more than 400 acres that was first constructed in the 1940’s. Until 1986, it was owned by Union Carbide which produced carbamate pesticides at the site. It was acquired by Bayer in 2002, and now has more than 500 employees.
The CSB said it is also examining operator fatigue as a possible contributor to the accident. Unit operators worked very high overtime levels during the three months prior to the accident, averaging almost 20 hours a week of overtime. Operators repeatedly worked 12 hour days, and sometimes up to 18 hours, with very few days off. Bresland said, “We are concerned about the potential for operator fatigue, which can of course be an important factor in major accidents.”
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