By Gregory Hale
Deficiencies at the Sunoco Nederland, Texas crude oil terminal, including the company’s hot work policies and procedures as well as the contractors hired to execute the work led to burn injuries for seven workers, a federal agency found.
Those were some of the findings in the Chemical Safety and Hazard Investigation Board’s (CSB) final report highlighting safety lessons learned from the August 12, 2016 flash fire at the Sunoco facility.
“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,” said 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.”
Construction Plan
In April 2016, Sunoco’s Nederland terminal began construction on the installation of new aboveground storage tanks, with associated piping, and modifying existing piping to facilitate transfer of crude oil to and from tanks within their terminal, according to the report. To complete the required work for the installation, Sunoco hired L-Con, Inc. to complete the piping modifications, including proper fit and alignment, pipe cutting, and welding. The installation involved only a portion of the terminal’s operation and therefore only required isolation of specific tanks and piping to complete the work.
To complete the work as planned, L-Con subcontracted CARBER to cut and isolate piping segments, as required, according to the report. According to an agreement between Sunoco and L-Con, the area where work was to occur would not be clean or free of residual crude oil and would require the use of an isolation tool.
On August 11, 2016, the day prior to the incident, CARBER cut and isolated the piping section, which was 30 inches in diameter. CARBER used their company-specific isolation tools to isolate the pipe section, which contained residual crude oil, from workers and the hot work that would take place, according to the report. Once the section of piping was cut and isolated, L-Con could weld the required piping sections in place.
Upon commencing welding during the night shift of August 12, 2016, the residual crude oil in the pipe ignited, causing a flash fire and explosion, the report said.
The CSB determined the probable cause of the incident was Sunoco approving, and L-Con conducting, hot work activities on equipment that contained an explosive atmosphere that when exposed to an ignition source, resulted in an explosion event. Contributing to the incident was the ineffective implementation and execution of policies and procedures by Sunoco, L-Con, and CARBER.
Share Safety Lessons
“This is the second report that the agency has issued in the last two months,” said Board Member Sylvia Johnson. “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.”
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 it was inadequate to prevent the fire and explosion.
View of the section of piping where welding work was ongoing at the time of the incident. Fire damage shown on far right.
Source: CSB
Specifically, the CSB investigation found the pipe involved in the incident contained residual flammable crude oil which was not adequately cleaned or inerted prior to starting up hot work.
The CSB concluded 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.
“The CSB wants industry to look at existing regulations and guidance when implementing and developing their hot work practices and procedures,” said Supervisory Investigator Lauren Johnson. “There is a lot of information out there and it needs to be utilized properly.”
Citations
In February 2017, L-Con was cited and issued fines by OSHA for multiple violations of OSHA regulations, including not utilizing their company’s procedures to control potentially hazardous energy, lack of training of employees on recognizing and controlling hazardous energy sources, not confining the heat, sparks, and slag from welding activities, and for welding in the presence of explosive atmospheres such as uncleaned or improperly prepared equipment that previously contained flammable material.
L-Con and OSHA reached a Settlement Agreement, where L-Con received one other than serious violation for failing to ensure its subcontractor continuously monitored the isolation devices the subcontractor installed until the servicing work was completed or until the possibility of such accumulation no longer existed.
CARBER was also issued a serious citation from OSHA in February 2017 for violation of 29 CFR 1910.147(c)(4)(1).
OSHA did not issue citations to Sunoco. The Sunoco Nederland terminal is regulated by the Pipeline and Hazardous Materials Safety Administration (PHMSA). At the time of the 2016 incident, Sunoco Partners Marketing and Terminals (SPMT) considered the area of the incident to be exempt from the jurisdiction of PHMSA. However, PHMSA cited Sunoco with failure to report the incident, according to the agency’s regulatory requirements.
Sunoco and L-Con developed plans and procedures to provide employees with guidance on how to safely conduct hot work operations. However, the CSB said the plans and procedures were inadequate to prevent the fire and explosion that occurred at the Nederland terminal. Sunoco, and subsequently L-Con, did not ensure adequate mitigation strategies were implemented to prevent a fire/explosion during hot work activities.
While the CSB was not able to determine the specific causal scenario, it concluded there had to be a fuel source in the presence of an ignition source and oxygen for the incident to occur.
Key Findings
The following are key findings from the report:
- Sunoco’s Hot Work procedure did not adequately state that hot work on equipment that contained or previously contained flammable material, was not permitted by OSHA or NFPA 51B, nor did the procedure clearly explain how to ensure equipment shall be cleaned or decontaminated to safely conduct hot work.
- The weather at the time of the incident contributed to the existence of flammable vapors inside the pipe.
- The vapor/air mixture inside the pipe was flammable.
- The atmosphere inside the pipe at the time of the incident was explosive, due to confinement of the flammable atmosphere by the CARBER isolation tools and ignited when exposed to an ignition source.
- Purging the pipe with an inert gas, such as nitrogen, would have prevented the incident from occurring by eliminating the flammable atmosphere inside the pipe.
To prevent chemical incidents, and in the interest of driving chemical safety change, the CSB urges companies that conduct hot work in facilities with flammable materials to review these key lessons:
- 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.
Click here to read the full CSB report.