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Screenshot from the video released by the the U.S. Chemical Safety and Hazard Investigation Board (USCSB).
08 Dec 2022

Ignored warnings: Investigators release lessons learned video from the deadly Loy-Lange boiler explosion

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A diagram showing how the debris went flying into nearby businesses. From the intitial 2017 report by the US Chemical Safety Board.
A diagram showing how the debris went flying into nearby businesses. From the inititial 2017 report by the US Chemical Safety Board.

The U.S. Chemical Safety and Hazard Investigation Board (USCSB) released a video on Wednesday outlining new details on the deadly 2017 boiler explosion at the Loy-Lange Box Company in St. Louis.

According to an article on KSDK.com featuring the incident,  a boiler at the Loy-Lange Box Co in S:t Louise exploded on the morning of April 3, 2017. The explosion was powerful and  launched flying debris the size of a full-sized van almost 500 feet / 150 meters away. The heavy debris came crashing down through the roof of another business in the area.

One Loy-Lange employee and three  employees in the neighbouring business  were killed by the cascading debris.

The 17-minute video (shown below in this article) covers the details of the investigation into what caused the explosion. Investigators said a part of the steam system called a semi-closed receiver (SCR) was not properly repaired, which eventually lead to the deadly incident. 

According to the US Chemical Safety Board,  It was called a Semi-Closed Receiver (SCR), because it received condensed steam (hot, high pressure water) from the LLBC steam system. “Semi-closed” refers to an open vent from the tank that vents any air in the system (and a small amount of steam from the hot water) to the atmosphere.

This, and more, can be also read in the original investigation report from 2017, which contains even more details.  

 

A blueprint of the boiler by the US Chemical Safety Board.
A blueprint of the boiler system from the initial 2017 report by the US Chemical Safety Board. 

 

In the new video, released this week,  the U.S. Chemical Safety and Hazard Investigation Board (USCSB) claims the incident could have potentially been avoided if inspections by the National Board of Boiler and Pressure Vessel Inspectors or a St. Louis city inspection had been able to catch the issues in advance.

"Prior to its failure, Loy-Lange ran the pressure vessel normally despite knowing that it was leaking," the video said. "It was a safety emergency that unfolded in plain sight."

Investigators said employees reported a leak at the bottom of the semi closed receiver the Friday before the explosion. A  welding company was called to inspect it, but they were wot not able to come until the following Monday. 

The system continued running the rest of the day Friday, and employees restarted the system normally the following Monday. A little more than an hour later, the explosion sent debris parts as large as 14 feet (4,3 meters) flying through the air. 

 

Read the full article on the report at KSDK.com

 

Photo Credit: The cover photo is a creenshot from the animated video released by the the U.S. Chemical Safety and Hazard Investigation Board (USCSB). The illustrations in the text are from original 2017 incident report.