On Nov. 15, 2014, four workers died and a fifth was hospitalized after exposure to a 24,000-pound methyl mercaptan leak at a DuPont plant in La Porte, Texas. The leak occurred in a building that was positioned over chemical plant piping, which included a failed valve. The Chemical Safety Board investigation later found that the valve had no documented function and served no manufacturing purpose. The enclosed office space was not designed to be a confined space, and hazard assessments did not identify Immediately Dangerous to Life and Health (IDLH) risks within the space. However, the workers were overcome by toxic gas while doing normal work there.
This month we look at the DuPont La Porte incident and three other incidents where workers were overcome by toxic or oxygen-displacing gases while performing routine work. In each of these situations, the risk of personal exposure to IDLH atmospheres was either not identified or underestimated by management or the workers operating in those environments.