Chemical Safety Board begins 2 new investigations

After clearing a large backlog of investigation reports, the US Chemical Safety and Hazard Investigation Board (CSB) announced April 4 that it will begin two new inquiries into toxic releases at Louisiana chemical plants last year.

The incidents led to the release of hydrogen fluoride and chlorine at Honeywell’s site at Geismar in January 2023 and the release of ethylene oxide at Dow’s Plaquemine facility in July 2023.

According to the CSB, a rupture in a heat exchanger at Honeywell led to an explosion and the release of approximately 470 kg of hydrogen fluoride and 770 kg of chlorine. Local officials closed nearby highways, and facility workers sheltered in place. No injuries were reported. Property damage at the facility is estimated at $4 million.

The incident at Dow occurred in a glycol manufacturing unit after an explosion in a pipe that’s part of a pressure relief system for ethylene oxide. Hot combustion gases entered a distillation column reflux drum, creating high-pressure conditions that ruptured the pressure vessel. Ethylene oxide passed through the rupturedvessel and reached air inside downstream piping; that triggered a fire and anotherexplosion, the CSB says.

Local officials issued a shelter-in-place order for hundreds of residents within about 1 km of the plant. No injuries were reported, and property damage has not been determined.

“Fortunately, no one was seriously injured or killed in either of these two events, but both involved the release of highly toxic chemicals that could have put workers and nearby residents at serious risk under different circumstances,” CSB chairperson Steve Owens says in a statement. “Because we recently completely eliminated the CSB’s long-standing backlog of investigation reports, we now have the ability to address other serious chemical incidents.”

Both events were revealed through the CSB’s long delayed but newly implemented incident reporting requirement.

Hydrogen fluoride is among several chemicals of concern that the CSB has noted in past investigations. Owens has previously said that the agency will continue urging regulators to prioritize inspections of refineries that use hydrofluoric acid, a highly toxic acid, as an alkylation catalyst. Such units have been the subject of several CSB investigations and recommendations.

CSB is an independent government agency with the authority to investigate chemically related incidents and recommend changes.