Chemical Safety Board releases Volume 4 of Incident Reports
The U.S. Chemical Safety and Hazard Investigation Board (CSB) has released Volume 4 of its Incident Reports, detailing 13 major chemical incidents across seven states and reporting more than $1 billion in property damage.
According to the CSB, the incidents occurred in California, Indiana, Louisiana, Tennessee, Texas, Utah, and Virginia. The events resulted in two fatalities and 10 serious injuries. Each report summarizes the incident and identifies a probable cause based on information submitted under the agency’s Accidental Release Reporting Rule.
Among the incidents is a January 30, 2023, argon gas release at Northrop Grumman Bacchus Propulsion Systems in Magna, Utah. The release occurred in an enclosed work area and led to the asphyxiation deaths of two employees. The agency said the event highlights risks associated with inert gases in confined spaces.
Volume 4 also examines two 2025 incidents involving workers who mistakenly disassembled active equipment.
On February 1, 2025, contract workers at the PBF Energy Martinez Refinery in Martinez, California, opened a pipe flange on an active system during turnaround preparation. The release and ignition of flammable hydrocarbons led to an explosion and fire. PBF Energy estimated property damage at approximately $924 million.
On May 20, 2025, a maintenance worker at Olin Corporation’s facility in Freeport, Texas, disassembled a rupture disc holder connected to an active chlorine system. The release of approximately 8,000 pounds of chlorine gas caused one serious injury and an estimated $23 million in property damage. The incident also prompted a shelter-in-place order for the surrounding community. The agency reported that a nearly identical piping system had been isolated and tagged, while the active system was not.
The board said the Olin and PBF Energy incidents reflect a broader pattern of serious accidents linked to ineffective safety management systems governing the opening of process equipment. The agency noted similarities to an October 10, 2024, incident at the PEMEX refinery in Deer Park, Texas, where workers opened the wrong piping flange, releasing hydrogen sulfide gas and causing two fatalities and 13 injuries. A final investigation report on the PEMEX incident is expected soon.
The CSB began publishing Incident Reports in January 2025 and releases them regularly on its website. Across four volumes, the agency has summarized 81 serious chemical incidents in 31 states, involving 16 fatalities, 75 serious injuries, and more than $4.5 billion in property damage.
The CSB is an independent federal agency that investigates catastrophic releases of hazardous substances. It does not issue fines or citations but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies, including OSHA and the Environmental Protection Agency.