Final Report on 2014 Fatal Chemical Release Outlines Safety Deficiencies

Flawed engineering design and a lack of adequate safeguards caused the fatal chemical release at the DuPont chemical manufacturing facility in La Porte, Texas, on Nov. 15, 2014, the U.S. Chemical Safety and Hazard Investigation Board has determined. CSB’s findings are included in its final investigation report on the incident, which was published in late June.

In November 2014, four workers were killed when approximately 24,000 pounds of methyl mercaptan, a toxic chemical used in the plant’s insecticide manufacturing process, was released into the air inside a manufacturing building. The facility has since been closed, but CSB stresses that the incident offers important lessons for the chemical industry related to emergency planning and response, process safety management systems, and safety culture.

In the days leading to the incident, operations personnel worked to clear blocked piping outside the manufacturing building. On the night of Nov. 15, 2014, two workers were sent to troubleshoot a high-pressure issue that they thought was related to a longstanding problem with process condensate. CSB’s report states that the workers believed the liquid in the vent header piping was mostly water, and that personnel had previously drained the vent header inside the building to remove process condensate and reduce system pressure. The agency notes that the pressure problem was instead related to the previous days’ clearing activities, and personnel did not realize that liquid methyl mercaptan was causing the high pressure. When a worker manually opened two sets of drain valves on the vent header piping, the methyl mercaptan escaped and vaporized. According to CSB, ineffective implementation of DuPont La Porte’s process safety management system resulted in the deaths of the four workers during the chemical release and led to the decision to close the facility.

“Once the methyl mercaptan release began, an ineffective emergency response program at La Porte contributed to the extent and duration of the chemical release, placed other workers in harm’s way, and did not effectively evaluate whether the chemical release posed a safety threat to the public,” CSB’s report reads.

The final report identifies more than 20 “key lessons” from the November 2014 chemical release that CSB says the chemical industry can use to help prevent future incidents. The agency urges companies to update emergency-planning documents when pertinent hazards are identified and recommends that facilities equip high-hazard areas with adequate detectors, alarms, and surveillance technology to identify whether there is a chemical release and if workers are affected. Dispersion modeling of chemical releases and monitoring for hazardous gases are among the other items addressed in the report’s recommendations.

For more information, see CSB’s press release. The full report is available as a PDF on the agency’s website.