New CSB Bulletin Hits the Basics of Safety
"Our investigation found that these accepted practices were conducted without appropriate safety hazard analysis, needlessly injuring these workers. It is important to remember that good safety practices are good maintenance practices and good business practices," CSB Chairperson Vanessa Allen Sutherland said.
A new safety bulletin released Sept. 18 by the U.S. Chemical Safety Board at its public business meeting on ExxonMobil Baton Rouge refinery fire hits the key basic elements of safety: organizational culture, human factors, the hierarchy of controls, and training. It all of these areas, it says the refinery fell short at the time of the Nov. 22, 2016, fire that severely burned four workers.
It occurred during maintenance activities when operators removed bolts that secured a piece of pressure-containing equipment to a plug valve. When the operators attempted to open the plug valve, the valve came apart and released flammable hydrocarbons that formed a vapor cloud and quickly ignited.
"Our investigation found that these accepted practices were conducted without appropriate safety hazard analysis, needlessly injuring these workers. It is important to remember that good safety practices are good maintenance practices and good business practices," CSB Chairperson Vanessa Allen Sutherland said.
Key lessons discussed in the bulletin include applying the hierarchy of controls to mitigate identified hazards, noting that an engineering control, such as improved valve design, is more effective than a lower-level administrative control, such as a sign warning workers that the gearbox support bracket connects to pressure-containing components. The board concluded that updating all of the older valves to the safer valve design, as was done to approximately 97 percent of the valves in the unit, would have ultimately prevented the fire.
"Our investigation also revealed a culture at the refinery that was accepting of operators performing maintenance on malfunctioning plug valve gearboxes without written procedures or adequate training, which in this instance resulted in a hazardous event," Investigator Mark Wingard said.
The key lessons:
- Evaluate human factors - interactions among humans and other elements of a system - associated with operational difficulties that exist at a facility in relation to machinery and other equipment, especially when the equipment is part of a process covered by OSHA's Process Safety Management standard. Apply the hierarchy of controls to mitigate the identified hazards.
- Establish detailed and accurate procedures for workers performing potentially hazardous work, including job tasks such as removing an inoperable gearbox.
- Provide training to ensure workers can perform all anticipated job tasks safely. The training should include a focus on processes and equipment to improve hazard awareness and help prevent chemical incidents.