A rupture in an off-line reboiler that was in standby mode, next to a boiler that was in operation resulted in the deadly explosion at the Williams Olefins chemical plant in Geismar, LA, in June.
The company said three elements contributed to the explosion that killed 2 and injured 77:
• The unexpected presence of liquid hydrocarbons in the reboiler in standby mode.
• The introduction of heat into the standby reboiler.
• The pressure relief system was isolated from the reboiler which was in standby mode.
When the standby reboiler ruptured, a vapor cloud released and that ignited via an unknown source.
The deadly June 13 blast released more than 62,000 pounds of toxic chemicals during the accident that killed two workers and injured 114 others, a new report said.
The facility released 31,187 pounds of volatile organic carbon material; 23,090 pounds of propylene; 2,398 pounds of ethylene; 5,621 pounds of other volatile organic carbon materials, including propane; and 48 pounds of benzene, according to the report filed with the state Department of Environmental Quality (DEQ).
At the time of the accident, air monitoring did not detect harmful amounts of chemicals in the air, but there was a “shelter in place” advisory for residents to remain in their homes, with windows and doors shut, Environmental Protection Agency (EPA) officials said at the time. DEQ reported monitoring on the day of the accident and the two days afterward found no unsafe levels of chemicals and that Williams Olefins reported its air monitoring also showed no measurable levels of chemicals in the air.
The Occupational Safety and Health Administration (OSHA) and the U.S. Chemical Safety Board are also investigating the incident.