CSB Investigates Hazardous Releases at Dow, Honeywell Performance Materials Plants

Dow reported to the CSB that a detonation occurred in a pipe segment at the Plaquemine facility for an EtO pressure relief system within a glycol manufacturing unit. Hot combustion gases subsequently entered a distillation column reflux drum, creating high-pressure conditions that ruptured the pressure vessel. EtO that passed through the rupture disc contacted air within the downstream piping, triggering a fire and an explosion.

Local officials ordered a shelter-in-place for hundreds of residents within a half-mile of the plant. No injuries were reported. The dollar amount of the property damage has not yet been determined.

The companies reported the incidents to the CSB in accordance with the agency’s accidental release reporting rule. After clearing a backlog of investigation reports, the agency is now turning its attention to other serious chemical incidents logged under its accidental release reporting rule, said CSB Chairperson Steve Owens.

“Fortunately no one was seriously injured or killed in either of these two events, but both involved the release of highly toxic chemicals -- hydrogen fluoride and chlorine at the Honeywell facility and ethylene oxide at the Dow facility -- that could have put workers and nearby residents at serious risk under different circumstances,” he said in a news release. “We want to make sure that similar incidents do not happen again at these facilities.”