Deficiencies in a company’s hot work policies and procedures led to the 2016 flash fire and explosion at the Sunoco Nederland, Texas, crude oil facility, which resulted in burn injuries to seven workers.
The U.S. Chemical Safety and Hazard Investigation Board (CSB) released its final report on the incident Sept. 28, detailing how the company, and a contractor involved in the incident, failed to provide adequate hot work policies.
Welding done in pipe that contained residual crude oil
Hot work was being conducted on Aug. 12, 2016, by L-Con, a contractor of Sunoco, on a segment of pipe that contained residual crude oil. This section of pipe was plugged on both ends with isolation devices. The isolation devices had been installed by CARBER, a contractor for L-Con.
When workers began welding on the inside surface of a flange, vapor inside the pipe gathered between two of the installed isolation tools and ignited. This caused a build-up in pressure, leading to a violent explosion at both ends of the isolated pipe.
Procedures didn’t address cleaning
The CSB found that both Sunoco and L-Con had procedures for hot work operations but the guidance in those procedures was inadequate since it didn’t address the residual crude oil inside the pipe, which should have been cleaned before work began.
Sunoco’s hot work procedure didn’t adequately state that hot work on equipment that had contained flammable material was not permitted by OSHA or National Fire Protection Association (NFPA) regulations. The procedure also failed to clearly explain how to ensure equipment was to be cleaned to safely conduct hot work. L-Con’s procedures had similar deficiencies.
CSB: Hot work incidents are common, preventable
Hot work incidents are a common problem “at a variety of facilities across the U.S. even though these are well-understood events and are avoidable,” according to CSB Interim Executive Authority Steve Owens.
“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,” Owens added.
The CSB said that for the industry to avoid a similar incident, it should focus on:
- proper isolation of equipment using OSHA regulatory requirements and NFPA guidance
- thorough identification and assessment of the locations of all flammables and combustibles in hot work, and
- the CSB’s 2010 Hot Work bulletin, which provides several methods for preventing hot work incidents, including using alternative methods, analyzing and controlling the hazards, conducting effective monitoring, and testing the general area for potential flammable conditions.