An inadequate process safety culture and a lack of proper inspection programs led to the 2017 industrial boiler explosion that killed four people at the Loy-Lange Box Company in St. Louis, according to the U.S. Chemical Safety and Hazard Investigation Board (CSB).
The CSB released its final investigation report on the incident July 29, finding that the fatal explosion was the result of the catastrophic failure of a severely corroded pressure vessel inside the boiler.
Lack of inspection program was contributing cause
The incident occurred April 3, 2017, when a large industrial boiler exploded at the Loy-Lange Box Company in St. Louis, launching a substantial piece of the 3,000-pound steam boiler about 500 feet through the air before crashing through the roof of the nearby Faultless Healthcare Linen building.
One worker was killed in the explosion at the box company, and two bystanders were struck and killed by the boiler when it crashed into the neighboring business. A third bystander was trapped under the boiler where it landed and later died as a result of his injuries.
CSB investigators found several safety issues, including:
- corrosion thinned the pressure vessel bottom head until it could no longer contain the pressure inside the vessel, with the company’s operating procedures failing to prevent the corrosion
- the company knew about the corrosion as early as 2004 but had no inspection program to monitor or mitigate the problem inside the vessel
- a repair made to the pressure vessel in 2012 didn’t adhere to inspection code requirements and left material in place that was thinner than required, which resulted in the failure that caused the explosion, and
- the company failed to establish a strong process safety culture and lacked programs that could have identified and mitigated the hazard.
Operational, policy, process safety deficiencies to blame
Ultimately, the CSB found the incident was caused by deficiencies in Loy-Lange’s operations, policies and process safety practices that failed to prevent the corrosion in the pressure vessel, leading to the boiler explosion.
The CSB recommended the company:
- develop and implement a comprehensive safety management system that includes elements recommended in industry guidance publications
- engage a qualified third party to conduct audits of its regulatory compliance practices and current compliance status, and
- implement an electronic records and data management system that preserves all critical company records, safety policies and procedures, and operational data while ensuring these records can be accessed remotely in the event of a catastrophic incident.