It could have been so much worse. What could have been a historic industrial tragedy is now being remembered and utilized as a teaching tool.
On Aug. 6, 2012, the Chevron U.S.A. Inc. Refinery in Richmond, California, experienced a catastrophic rupture of the No. 4 sidecut piping in one of the refinery’s crude units. At the time of the incident, light gas oil was flowing through an 8 inch line at a rate of approximately 10,800 bpd and a temperature of 640 F.
“There was a leak that occurred on this line initially, so there were a lot of people from Chevron who were in the area trying to figure out what to do about it,” explained U.S. Chemical Safety and Hazard Investigation Board Chemical Incident Investigator Steve Cutchen.
When the line blew, 19 employees were enveloped by an opaque vapor cloud that eventually ignited.
“They said they couldn’t see their hands in front of their faces,” Cutchen said, recounting the incident to delegates to the Texas/Louisiana EHS Seminar recently in Galveston, Texas.
“The guys on hoses were following the hoses to find their way out. There were other people who dropped down to their hands and knees and started feeling around for something that would help them get their bearing so they could find a way out of this cloud.”
All but one Chevron employee, a pump operator in his fire truck, escaped the vapor cloud prior to ignition.
“He got on the radio and called Mayday, but he got no answer,” Cutchen said.
Trusting his pumper gear and training, the operator “made a run for it.”
“When he came out of the fire, one of his colleagues said he looked like he was coming through the gates of hell,” Cutchen said.
Fortunately, all 19 workers sustained only minor injuries both during the ignition and the incident and throughout the subsequent emergency response.
More than 15,000 members of the public sought medical treatment after having been exposed to the vapor cloud that drifted across the bay, but none were injured or impaired.
“The damage mechanism that caused the failure is called sulfidation,” Cutchen explained. “Sulfidation is a reaction that’s common in the refining industry. It’s when sulfur compounds react with the steel.”
In the 10 years prior to the incident, a small number of Chevron personnel with knowledge and understanding of sulfidation corrosion made recommendations to increase inspections or upgrade the material of construction in that No. 4 sidecut piping.
Cutchen said those recommendations were not effectively implemented, adding several employees observing the leak had informally suggested a shutdown.
“We asked them, ‘Well, did you actually do that as a stop-work order? Did you state it explicitly?’”
The employees said they hadn’t, believing managers and supervisors would implement an order to stop an operation of that magnitude and scope.
“‘They’ve got the same information I’ve got, and they’re brighter than I am,’” Cutchen said the workers reasoned.
Cutchen admitted it might be difficult for workers to initiate a stop-work order during the process mode.
“It takes a certain amount of courage to be the one to stand up,” he said. “But stop-work is a vitally important aspect of any company’s safety culture. It might be the last, best thing you’ve got to prevent an accident like this.”
Cutchen added safety culture is neither a feeling nor an attitude but an action verb.
“Safety culture is a practice of the entire organization, and how we work together,” Cutchen concluded. “We have to learn from what’s being reported, process that information, then make changes. If you’re not making changes, you’re not doing it right.”
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