Federal investigators detailed deadly hydrogen sulfide and ethylene oxide releases and noted recurring equipment identification and vessel closure failures across several states.
The U.S. Chemical Safety and Hazard Investigation Board released a new volume of incident reports and two final investigation findings masking fatal and high-outcome chemical releases in Texas and Louisiana.
The agency, based in Washington, D.C., stated Volume 4 of its Incident Reports summarizes 13-serious chemical incidents in California, Indiana, Louisiana, Tennessee, Texas, Utah and Virginia. As per the CSB, the events led to 2-fatalities, 10 critical injuries and more than $1 billion in property damage. The reports are based on information submitted underneath the organization’s Accidental Release Reporting Rule.
Among the incidents emphasized are two 2025 events including workers opening the wrong equipment all through renovation. At a refinery in Martinez, California, contract workers inadvertently opened a pipe flange on an active system during turnaround preparations, releasing and igniting flammable hydrocarbons and causing an predicted $924 million in damage, ap per the CSB. In Freeport, Texas, a maintenance worker disassembled a rupture disc holder in an active chlorine system, releasing about 8,000 pounds of chlorine, causing one critical injury and causing a shelter-in-place order. The CSB stated the piping had been wrong isolated and tagged.
As per the CSB, Incident Reports issued to date cover 81 serious incidents in 31 states involving 16 fatalities, 75 critical accidents and more than $4.5 billion in property damage.
Last month, the agency also unveiled its very last report at the Oct. 10, 2024, hydrogen sulfide launch at the PEMEX Deer Park Refinery in Deer Park, Texas. Two contract worker died and 13 others had been transported to medical centers after more than 27,000 pounds of hydrogen sulfide had been released throughout maintenance in the refinery’s amine unit, said the CSB.
As per the report, workers from Repcon Inc. Mistakenly opened a flange on piping containing pressurized hydrogen sulfide, instead of a nearby phase that were cleared. The release persisted for nearly an hour earlier than emergency responders stopped it.
The CSB concluded the incident resulted from a failure to positively identify the precise equipment earlier than opening the piping. Contributing elements included gaps in work allowing, risk assessments in an active unit and deviations from mounted methods. The agency issued recommendations to the refinery and to the American Society of Mechanical Engineers to develop guidance for marking equipment prior to opening.
In a separate final report, the CSB detailed the July 14, 2023, explosions and ethylene oxide release at Dow Chemical Company’s Louisiana Operations Glycol II plant in Plaquemine. As per the agency, more than 31,000 pounds of ethylene oxide had been launched after a reflux drum catastrophically failed, prompting a refuge-in-region order impacting lots of residents.
The CSB determined the incident start when ethylene oxide entered pressure relief piping that contained air and ignited. Metal debris from portable work lights inside a reflux drum in the course of prior renovation punctured a rupture disc, permitting the material to go into the piping. The agency also cited inadequate vessel closure practices, failure to maintain an inert atmosphere in pressure relief piping and pressure relief system layout that permit flame propagation into the drum.
As a result, the CSB issued tips to Dow and to standards organizations, such as the National Fire Protection Association and the American Society of Safety Professionals, targeted toward enhancing vessel closure verification, inverting controls and confined space guidance.
