The U.S. Chemical Safety and Hazard Investigation Board (CSB) has issued an update on its ongoing investigation into a fatal incident at Techniques Surfaces USA (TS USA) in Chattanooga, Tennessee. On May 30, 2024, an accidental release of molten sodium hydroxide and sodium nitrate killed one employee and injured another at the liquid nitriding facility.
TS USA began operations in 2017, specializing in liquid nitriding for large, heavy parts. This process enhances wear resistance in metals by diffusing nitrogen into the material, crucial for automotive, aerospace and manufacturing industries.
The incident occurred when rollers, left overnight in a hot water rinse bath, were reintroduced directly into the oxidizing bath without preheating. This decision, made after consulting a remote process engineer, led to a molten salt eruption and subsequent fires.
CSB Chairperson Steve Owens emphasized the agency's commitment to public transparency and prevention of similar incidents. The investigation continues to focus on the eruption's cause, hazard analyses, safety management systems, corporate governance of safety programs, and industry guidance for liquid nitriding facilities.
The CSB, whose board members are presidentially appointed and Senate-confirmed, issues safety recommendations rather than citations or fines.
