Ignored Warnings: Explosion in St. Louis

Summary

The Loy-Lange Box Company in St. Louis experienced a catastrophic explosion on April 3, 2017, when a corroded pressure vessel failed, killing four people. The Chemical Safety Board (CSB) found multiple safety failures, including poor corrosion management, ineffective repairs, inadequate inspections, and deficient safety systems. Despite known corrosion issues, the vessel continued to operate. The CSB recommended significant improvements in repair protocols, inspection standards, and safety management practices to prevent similar incidents in the future.

Takeaways

• 😀 A pressure vessel failure at Loy-Lange Box Company in St. Louis in 2017 resulted in four fatalities, caused by a catastrophic BLEVE (boiling liquid expanding vapor explosion).
• 😀 The Chemical Safety Board (CSB) found that the explosion was due to ineffective corrosion management, inadequate repairs, lack of inspections, and deficient safety systems at the facility.
• 😀 Loy-Lange's steam system used oxygenated water, which caused corrosion in the steel pressure vessels, contributing to multiple leaks over the years.
• 😀 The pressure vessel (Semi-Closed Receiver, or SCR) experienced thinning of steel due to corrosion, which was a known hazard but poorly managed by Loy-Lange.
• 😀 Despite leaks being identified, Loy-Lange continued to operate the corroded vessel without addressing the root cause of the corrosion, including a repair made in 2012 that did not meet required safety standards.
• 😀 On March 31, 2017, operators noticed a leak from the SCR, but the issue was left unresolved until April 3, when the vessel failed during the startup process.
• 😀 The failure occurred when the pressure vessel was exposed to atmospheric pressure, causing water inside to flash into steam and explode.
• 😀 The explosion sent the SCR 520 feet into a neighboring building, damaging multiple structures and resulting in the deaths of a Loy-Lange operator and three employees from a nearby business.
• 😀 The CSB identified four critical safety issues: uncontrolled corrosion, ineffective repairs, lack of inspections, and deficient safety management systems.
• 😀 The CSB made recommendations to both Loy-Lange and regulatory bodies, including improving corrosion management, revising inspection standards, and ensuring better adherence to repair codes to prevent similar incidents in the future.

Q & A

What caused the explosion at the Loy-Lange Box Company?

The explosion was caused by the catastrophic failure of a pressure vessel, which was compromised due to uncontrolled corrosion, ineffective repairs, and poor safety management. A leaking pressure vessel, left in operation despite known risks, ultimately failed when exposed to atmospheric pressure.

What specific role did corrosion play in the incident?

Corrosion, specifically from oxygenated water entering the pressure vessel during startup, caused significant thinning of the vessel's steel. Over time, this weakened the vessel, making it susceptible to failure. The inadequate management of corrosion was a primary factor in the incident.

How did Loy-Lange's repair practices contribute to the explosion?

In 2012, a repair to the bottom head of the pressure vessel left a corroded steel ring in place, which continued to degrade for five years. The repair did not meet required safety codes and was deemed ineffective, allowing the corrosion to eventually cause the vessel’s failure.

Why was the pressure vessel not inspected properly?

Loy-Lange never registered the pressure vessel with the city, meaning there was no proactive inspection process. The St. Louis city code required annual inspections, but no city inspectors had checked the vessel, leading to missed opportunities to detect the corrosion hazard before the explosion.

What was the role of the city of St. Louis in the incident?

The city of St. Louis failed to inspect the pressure vessel as required by local code, as the SCR was unregistered. The lack of inspections contributed to the inability to catch corrosion issues early. The city later updated its inspection requirements after the incident.

What was the role of the startup process in the failure?

During the startup process, oxygenated water entered the pressure vessel due to improper heating and chemical treatment of the makeup tank water. This water, which was not adequately deoxygenated, increased the corrosion risk within the vessel.

What safety management issues were identified by the CSB?

Loy-Lange lacked an effective safety management system to identify, assess, and address corrosion hazards. They failed to implement proper maintenance, inspections, and corrective actions, and they continued to operate a leaking pressure vessel without taking adequate safety precautions.

What were the CSB’s recommendations to prevent such incidents in the future?

The CSB recommended several changes, including updating inspection procedures for pressure vessel repairs, revising the St. Louis mechanical code to include national standards for inspections, and requiring Loy-Lange to implement a comprehensive safety management system to address corrosion and prevent similar failures.

How did the CSB suggest improving pressure vessel repair practices?

The CSB recommended that the National Board of Boiler and Pressure Vessel Inspectors update their inspection rules to include more prescriptive steps during repairs, ensuring that repairs are performed correctly and that non-conforming work is not accepted.

What was the specific type of explosion that occurred, and how did it unfold?

The explosion was a Boiling Liquid Expanding Vapor Explosion (BLEVE). When the pressure vessel was exposed to atmospheric pressure, the water inside rapidly turned into steam, causing a violent expansion and launch of the vessel. The explosion resulted in the fatalities of four people.