WASHINGTON, D.C. -- The CSB has released its final report into a 2017 explosion that occurred at the Loy-Lange box company in St. Louis, MO and resulted in the death of four people.

The incident occurred when a pressure vessel catastrophically failed fatally injuring one employee at the company and launching the pressure vessel from the building and through the roof of a nearby business, fatally injuring three members of the public.

The Chemical Safety Board investigated and found that over the course of many years, an area of the failed pressure vessel had thinned due to a known corrosion mechanism that was poorly controlled.  The CSB also found that Loy-Lange repeatedly ignored clear warnings that corrosion was causing major problems within its operations. In fact, prior to its failure, Loy- Lange ran the pressure vessel normally despite knowing that it was leaking.

CSB Interim Executive Steve Owens said, “A tragic series of circumstances contributed to the explosion at Loy-Lange: ineffective corrosion management, poor pressure vessel repair, a lack of inspections of the vessel, and the absence of sound safety management systems. Those factors led to a severely corroded pressure vessel that presented a serious safety hazard but was allowed to operate until it ultimately failed, taking the lives of four people.”

The CSB determined that the cause of the explosion was deficiencies in Loy-Lange’s operations, policies, and process safety practices that failed to prevent or mitigate chronic corrosion.

Furthermore, the CSB determined that contributing to the incident was the City of St. Louis’s missed opportunities to identify and ensure proper inspections, identify an inadequate repair and existing gaps in inspection requirements. 

As a result of its findings the CSB identified four safety issues and is issuing recommendations to Loy-Lange, the City and Mayor of St. Louis, the inspection company Arise, and the National Board of Boiler and Pressure Vessel Inspectors.