The incident at Catalyst Refiners in Nitro, West Virginia included the release of toxic hydrogen sulfide gas during equipment cleaning and decommissioning, killing two workers.
The U.S. Chemical Safety and Hazard Investigation Board declared April 23 it is opening an investigation into a fatal chemical release that happened the previous day at the Catalyst Refiners, Inc. facility in Nitro, West Virginia, which resulted in two worker fatalities and injured numerous others.
Catalyst Refiners manages silver and ethylene oxide catalyst refining operations and is owned by the Ames Goldsmith Corporation.
As per first information from the CSB, the incident happened during the cleaning and decommissioning of equipment at the facility when nitric acid and another substance were reportedly mixed, generating and releasing toxic hydrogen sulfide gas inside a building where several employees were present. In addition to the two fatalities, more than 30 people sought medical care, including one reported to be in critical condition. A shelter-in-place order was also issued for the surrounding community.
“We are Launches an investigation into this tragic incident to identifies how it happened and identify ways to support prevent something like this from happening again,” stated CSB Chairperson Steve Owens.
The investigation follows current safety-related activity by the CSB. In March, the agency issued a Safety Spotlight detecting the American Fuel and Petrochemical producers for voluntarily implementing safety guidance for fluid catalytic cracking units stemming from the CSB’s investigation into the 2018 Husky Energy refinery explosion in Superior, Wisconsin. That initiative included 18-person workshops reaching more than 700 participants from 76 refineries across the U.S. and Canada.
Earlier, in November 2025, St. Louis implemented updates to its Mechanical Code for in-service boiler and pressure vessel inspections following CSB recommendations stemming from a fatal 2017 explosion at the Loy-Lange Box Company.
