The CSB published its report on the 2017 tank explosions at the Midland Resource Recovery facility in Philippi, West Virginia. Two separate tank explosions occurred, killing three workers.
Midland Resource Recovery cleaned natural gas odorizer equipment before disposal to remove the mercaptan odor. They cleaned the equipment by treating the equipment with sodium hypochlorite. The CSB hypothesizes that Midland Resource Recovery had unintentionally reacted chemicals in the odorizer equipment to produce alkyl hypochlorites, which are thermally unstable and highly explosive.
The CSB found that there was not an effective safety management system in place to identify and control hazards from reactive chemicals. Among other things, MRR had no formal hazard identification process in place to analyze or characterize what chemicals were inside the odorizer vessels-and in what quantity-before decommissioning and chemically treating this equipment with sodium hypochlorite. The company also lacked effective safeguards to prevent unexpected or uncontrolled chemical reactions.
The CSB provides the following key lessons for companies that deal with reactive chemistry:
1. Companies need a robust safety management system in place to prevent reactive chemical incidents. If a process has the potential for uncontrolled chemical reactions to occur, the company should conduct a formal evaluation of the reactive chemistry, perform a hazard analysis, and ensure that sufficient safeguards are in place to prevent reactive chemical incidents.
2. Companies should have a thorough and complete understanding of their reactive chemistry under design conditions and under all foreseeable abnormal conditions. For example, companies should avoid treating uncharacterized waste materials with sodium hypochlorite because of the potential explosive hazards associated with its complex reactive chemistry.
The investigation report can be accessed at this link:
https://www.csb.gov/midland-resource-recovery-explosion-/------------------------------
Lauren Grim, PE,CFEI
Supervisory Chemical Incident Investigator
U.S. Chemical Safety Board
Denver, CO
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