TN Metal-Treating Firm Failed to Learn From Previous Incidents, Safety Board Says

A French-owned metal-treating company in Tennessee failed to utilize safety management and failed to implement lessons learned from previous incidents before a 2024 explosion that killed one worker and heavily damaged the site, the U.S. Chemical Safety and Hazard Investigation Board said in its final report on the accident.

“This terrible incident underscores how critically important it is for facilities like TS USA to have a comprehensive and effective safety management system in place,” CSB Chairperson Steve Owens said in a statement this week. “The absence of strong process-safety protocols—and the failure to apply lessons from past similar events—put TS USA’s workers at serious risk, with one of them tragically being killed.”

The TS USA plant in Chattanooga, part of the France-based HEF Groupe, hardens metals using a nitriding process. When a drain hole in a roller cylinder became clogged in a molten salt bath, the unit erupted and severely burned a worker, who later died, the safety board found. Three other worker were injured. The explosion resulted in multiple fires and $1.3 million in damage, forcing the facility to be shut down for eight months.

At least three similar incidents had happened at other facilities owned by HEF Groupe, including one at the Chattanooga plant a year earlier. But the parent company did not share information about how to prevent the situations with its facilities, the CFB report said.

The year-long investigation by the safety board did not appear to result in fines or other penalties for the company. The Tennessee Occupational Safety and Health Administration imposed a $6,600 penalty against the company.

The chemical board made several recommendations to improve safety at the plant:

• Installation of physical barriers to protect employees from molten salt releases
• Development and implementation of a comprehensive safety management system incorporating industry standards
• Creation of a corporate program to ensure that safety information is effectively communicated and enforced across all HEF Groupe facilities
• Establishment of a safety position, with a worker who has expertise and experience in safety management systems, at each TS USA facility.

The board also laid out key lessons for the metal-treating industry:

The full report can be seen here.

Photo: The TS USA facility in Chattanooga (Chemical Safety and Hazard Investigation Board).