Safety Teams Investigating After Tennessee Industrial Fire That Killed Worker

State and federal safety officials are investigating a fatal explosion and fire at a Chattanooga, Tennessee, steel-hardening facility.

The U.S. Chemical Safety and Hazard Investigation Board said it had sent a team to the TS USA liquid nitriding plant to interview workers and check documentation. The board does not issue fines but makes safety recommendations to companies and to federal safety regulators.

Also this week, the Tennessee Occupational Safety and Health Administration, a state version of OSHA, began investigating the incident, according to news reports.

The facility uses salt baths to harden steel by nitriding, or causing the steel to absorb nitrogen. The local fire department said a chemical reaction may have caused an explosion that severely burned the worker, whose name was not released, news outlets reported.

The TS USA plant is part of HEF Durferrit USA, based in Springfield, Ohio.