CSB Releases Final Investigation Report on 2016 Sunoco Oil Terminal Fire and Explosion in Texas


Washington D.C. September 28, 2022: Today the U.S. Chemical Safety and Hazard Investigation Board (CSB) released its final report on the 2016 flash fire and explosion at the Sunoco Nederland, Texas crude oil terminal, which resulted in burn injuries to seven workers.

The CSB’s investigation identified deficiencies in the company’s hot work policies and procedures as well as the contractors hired to execute the work. The CSB’s final report highlights key safety lessons learned from the incident at the Sunoco facility, which can prevent future hot work incidents.  

CSB Interim Executive Authority Steve Owens said, “The CSB continues to see hot work incidents at a variety of facilities across the U.S. even though these are well-understood events and are avoidable. Increased adherence by companies to existing regulations and industry guidance can  keep other hot work incidents from happening in the future and help protect workers from harm.”

On August 12, 2016, hot work was being conducted by L-Con, a contractor of Sunoco, on a section of pipe that contained residual crude oil. The pipe segment was plugged on both ends by CARBER, a contractor hired by L-CON using an isolation device. During the welding operation on the inside surface of a flange, vapor inside the pipe gathered between two of the installed isolation tools and ignited. The ignition caused a build-up in pressure which led to a violent explosion at either end of the isolated pipe.

Board Member Sylvia Johnson said, “This is the second report that the agency has issued in the last two months. We are committed to getting this information out to companies and workers – our goal is to share valuable safety lessons with companies that perform hot work activities every day.”

Both Sunoco and L-Con developed plans and procedures to provide employees with guidance on how to safely conduct hot work operations, but the CSB found that guidance was inadequate to prevent the fire and explosion. Specifically, the investigation found that the pipe involved in the incident contained residual flammable crude oil which was not adequately cleaned or inerted prior to commencing hot work.  

The CSB concluded that Sunoco’s hot work  procedure did not adequately state that hot work on equipment that currently or previously contained flammable material, was not permitted by OSHA or NFPA 51B. Additionally,  the procedure did not clearly explain how to ensure that equipment was to be cleaned or inerted to safely conduct hot work.  Therefore, Sunoco, and subsequently L-Con, did not implement adequate mitigation strategies to prevent a fire or explosion during hot work activities.

Supervisory Investigator Lauren Johnson said, “The CSB wants industry to look at existing regulations and guidance when implementing and developing their hot work practices and procedures. There is a lot of information out there and it needs to be utilized properly.”

The CSB identified three key lessons for industry to prevent a similar incident from occurring. These lessons include:

  • Proper isolation of equipment utilizing Occupational Safety and Health Administration’s (OSHA) regulatory requirement and National Fire Protection Association’s (NFPA) guidance
  • Thorough identification and assessment of the locations of all flammables and combustibles in hot work  
  • A reference to the CSB’s 2010 Hot Work bulletin with advises several methods for preventing hot work incidents including using alternative methods, analyzing and controlling the hazards, as well as conducting effective monitoring and testing the general area for potential flammable conditions.

The CSB has several resources available on safe hot work practices which can be found HERE.

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 Board Members are appointed by the President and confirmed by the Senate.  CSB investigations look into all aspects of chemical accidents and hazards, including physical causes, such as equipment failure, as well as inadequacies in regulations, industry standards, and safety management systems.

For further information contact Hillary Cohen, Communications Manager, at [email protected] or (202) 446-8094.  Further information about the agency’s public meetings may be found on the CSB website at: www.csb.gov.


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