CSB: Process Safety Failures Led to Fatal 2017 Explosion

A final report released by the U.S. Chemical Safety and Hazard Investigation Board faults a St. Louis employer’s deficient process safety management for a 2017 explosion that took the lives of four people. According to CSB, failures in the Loy-Lange box company’s policies, procedures, and operations, as well as an inadequate repair, led to the explosion of a pressure vessel on April 3, 2017. A worker died in the explosion, and the pressure vessel, which weighed 2,000 pounds, was launched into the air and through the roof of a laundromat 500 feet away, killing three members of the public.

CSB found that corrosion had thinned the metal of the pressure vessel over a period of years and that Loy-Lange’s startup practices likely contributed to the corrosion by introducing oxygenated water into the equipment. The CSB report states that Loy-Lange was aware of the corrosion as early as 2004 but did not institute a program for regularly inspecting the pressure vessel as called for by industry guidance documents.

In addition, the city of St. Louis, which has regulatory authority over pressure vessels operated within city limits, failed to inspect the equipment at Loy-Lange due to limited staffing and resources, according to the report.

Loy-Lange attempted to fix the pressure vessel in 2012, but the resulting repair removed only a portion of the corroded metal, and a subsequent inspection did not detect the problem. CSB says that the original steel left in place at the time is what ultimately failed five years later, causing the fatal explosion. A few days before the explosion, employees discovered that the pressure vessel was leaking, but a local welder contacted by Loy-Lange was unable to visit the facility at that time, and the company continued to operate the equipment as normal.

“Loy-Lange did not employ sound process safety management principles in addressing the risks associated with corrosion in its steam process,” the report reads. “It is essential that facilities with hazardous processes have an effective process safety management system to help ensure major incidents such as the Loy- Lange incident are prevented.”

More information is available on the CSB website.