CSB Releases New Safety Video on the 2020 Fatal Propylene Release and Explosion at the Watson Grinding Facility in Houston, Texas
Three People Died Due to the Blast
Washington D.C., February 25, 2025 - Today, the U.S. Chemical Safety and Hazard Investigation Board (CSB) released a new safety video on its investigation into the January 24, 2020, fatal propylene release and explosion at the Watson Grinding and Manufacturing Company facility in Houston, Texas. The massive explosion resulted in the death of two workers and a nearby resident and damaged hundreds of neighboring homes.
The CSB's new safety video, called “No Detection: Explosion at Watson Grinding,” includes an animation of the events leading to the incident, and commentary from CSB Chairperson Steve Owens and Investigator-In-Charge Benjamin Schrader.
Watson Grinding specialized in machining and grinding services as well as applying high-performance coatings – particularly High Velocity Oxygen Fuel, or HVOF, coating. The process of HVOF coating involved propylene – an extremely flammable hydrocarbon gas. The CSB found that sometime overnight prior to the incident, a hose disconnected from its fitting inside a booth used for the coating process, releasing flammable propylene that accumulated inside the coating building. By the time employees arrived at the facility early on the morning of January 24, an explosive concentration of propylene had formed inside the building. When one of the employees entered the building and turned on the lights, the flammable vapor ignited, triggering the explosion.
As in the CSB’s final report on the incident, the safety video covers the two key safety issues that contributed to the incident: process safety management and emergency preparedness. The video also highlights a safety recommendation made by the CSB to the Compressed Gas Association.
In the video Chairperson Owens states, “This deadly incident could have been prevented if Watson Grinding had implemented a process safety management system to address the hazards of its coating operation. And even if a leak still had taken place, an emergency response plan could have prevented the tragic loss of life that occurred. We urge companies to develop and implement effective process safety management systems and emergency response plans so that something like this never happens again.”
The CSB is an independent federal agency charged with investigating incidents and hazards that result, or may result, in the catastrophic release of extremely hazardous substances. The agency’s core mission activities include conducting incident investigations; formulating preventive or mitigative recommendations based on investigation findings and advocating for their implementation; issuing reports containing the findings, conclusions, and recommendations arising from incident investigations; and conducting studies on chemical hazards.
The agency's board members are appointed by the president subject to Senate confirmation. The Board does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA.
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