CSB commends St. Louis Board of Aldermen for implementing recommendations

Today the U.S. Chemical Safety and Hazard Investigation Board (CSB) commended the city of St. Louis, Missouri, Board of Aldermen for revising city inspection standards.

The Board of Aldermen implemented two recommendations from the CSB’s investigation of the tragic explosion at the Loy-Lange Box Company in April 2017 that killed four people.

“The Board of Aldermen have taken an extremely important step toward helping prevent another tragic incident like the one at Loy-Lange from happening again,” said Steve Owens, CSB chairperson.

On April 3, 2017, an explosion occurred at Loy-Lange when a pressure vessel catastrophically failed. The explosion fatally injured a Loy-Lange employee working nearby. The explosion also launched the 2,000-pound pressure vessel out of the Loy-Lange building into the air, after which the vessel crashed through the roof of a nearby business, killing three other people.

Two recommendations to Board in final report

When the CSB issued its final report on the investigation in July 2022, the agency recommended the Board of Aldermen revise the city’s Mechanical Code to adopt a national consensus standard, such as National Board Inspection Code (NBIC) Part 2, to govern the requirements for the in-service inspection of boilers and pressure vessels in the city.

The CSB also recommended that the Board of Aldermen revise the Mechanical Code to require that pressure vessel inspections be performed by an inspector meeting the National Board of Boiler and Pressure Vessel Inspectors’ (NBBI) standards for in-service (IS) inspections.

In response to the CSB recommendations, the Board of Aldermen recently approved revisions to the city’s Mechanical Code that standardize in-service inspections for pressure vessels and establish minimum qualifications for personnel conducting in-service inspections of boilers and pressure vessels.

The updated ordinance, which took effect Nov. 15, 2025, strengthens in-service inspections by requiring that they be conducted in accordance with the National Board Inspection Code. The updated ordinance also requires that such inspections be performed by a NBBI IS commissioned inspector.

One remaining recommendation yet to be implemented

The CSB issued a total of eight recommendations in its final report to Loy-Lange, Arise, Inc., NBBI, the Board of Aldermen, and the Mayor of St. Louis.

The only remaining open recommendation from the CSB’s Loy-Lange investigation was issued to the Mayor. The CSB recommended the Mayor distribute and communicate the findings of the CSB’s investigation report to all licensed stationary engineers and all entities in St. Louis registered as owning/operating boilers and pressure vessels in the city.

The CSB and the Mayor’s office have been actively communicating about the recommendation. The CSB said it is looking forward to the implementation of this final Loy-Lange recommendation in the near future.