CSB Releases Investigation Update into 2022 Fatal Naphtha Release and Fire at BP-Husky Refinery in Ohio

U.S. Chemical Safety Board, June 13, 2023

The U.S. Chemical Safety and Hazard Investigation Board (CSB) has released an update into its ongoing investigation of the chemical release and fire at the BP-Husky Refinery located in Oregon, Ohio that resulted in two fatalities and substantial property damage to the facility. The update gives details about the investigation including a summary of the process upset that led to the incident, background on the refinery, and an outline of the CSB’s activities moving forward.  

Chairperson Steve Owens said, “While the CSB’s investigation is still ongoing, we want to provide the public with important factual details surrounding this tragic incident as we know them now. Our investigation will use this and other information that we gather to make findings and recommendations to help prevent a similar tragedy from occurring in the future.

The CSB’s update details the events that occurred on September 20, 2022, including a timeline of key events:

  • On September 20, 2022, at approximately 6:09 p.m., flammable liquid naphtha began to fill a Fuel Gas Mix Drum (“Mix Drum”) at the BP-Husky Toledo Refinery. The liquid overflowed from the normally vapor-only Mix Drum, sending naphtha through vapor piping to various boilers and furnaces in the refinery. Several of these boilers and furnaces started to emit highly visible plumes of smoke. 
  • To decrease the level in the Mix Drum, at approximately 6:17 p.m. liquid naphtha was sent to the refinery flare system and drained to an oily water sewer. Starting at approximately 6:32 p.m., naphtha from the Mix Drum was also drained directly to the ground creating a vapor cloud.
  • At approximately 6:46 p.m., the vapor cloud of flammable naphtha that had formed on the ground reached an ignition source, which generated a large fire that fatally injured two employees and resulted in substantial property damage within the refinery.

Moving forward the CSB will analyze several key areas and how they may have applied to the incident including hierarchy of controls and existing regulations, industry standards, and guidance.

About the CSB

The CSB is an independent, non-regulatory federal agency whose mission is to drive chemical safety change through independent investigations to protect people and the environment. The agency’s board members are appointed by the President and confirmed by the Senate. CSB investigations look into all aspects of chemical incidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems. The CSB does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA. For more information, please visit

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