Two massive fuel storage tanks were destroyed in a 2019 explosion at the NuStar Energy tank farm near Crockett. (Contra Costa County Fire Protection District)
Contra Costa County fire investigators and elected officials say that a massive 2019 explosion and blaze at a fuel storage facility near Crockett shows the need for tighter safety regulations and improved inspections of such sites.
A report from Contra Costa County Fire Protection District investigators made public Tuesday found the Oct. 15, 2019, blast at the NuStar Energy tank farm was most likely caused by an electrical spark that touched off ethanol vapors in a huge storage tank.
The 18-month investigation also said improper ventilation in the tank also played a role in the incident. The initial explosion destroyed one tank, and the force of that blast demolished an adjacent tank and sparked a fire that burned for several hours and shut down nearby Interstate 80.
Each tank could hold 8.4 million gallons of fuel, but at the time of the blast they were both at 1% capacity, holding about 84,000 gallons of ethanol each.
No injuries of employees, firefighters or residents were reported. One contractor working at the site was briefly trapped by the fire, but escaped unharmed.
The explosion of the second tank can be seen at the 12-second mark in a video tweeted by Vallejo Fire:
The report estimated the incident caused $25 million in damage. Workplace safety regulator Cal/OSHA fined NuStar $225 for failing to identify unsafe working conditions.
Inspections prior to the fire and the investigation following the incident both found that measurement equipment inside the tank where the incident started was not properly grounded. Investigators also found the tank’s floor was coated with material that inhibited grounding and contributed to a build-up of static electricity.
The NuStar facility passed an inspection less than a year before the fire occurred, and recommended repairs were completed. But Contra Costa fire investigators said that such fuel storage facilities, often called tank farms, operate without the relatively strict safety regulations governing oil refineries.
Capt. Ryan Graham of the Contra Costa Fire District Investigation Unit said most inspections at fuel storage facilities like NuStar’s lack comprehensive safety oversight.
For instance, Graham said, most tank farm inspections are conducted by an industry body, the American Petroleum Institute. But there’s no central authority that oversees safety at storage facilities.
“There is no single agency that oversees everything, there are several agencies that look at their part, but no one that brings it all together,” Graham said.
Crockett-Carquinez Fire Chief Dean Colombo said the storage industry’s current safety standards are inadequate.
"This facility has been inspected a number of times and it had an excellent rating," despite potential electrical hazards, Colombo said. "The industry needs to accept that in their current configuration, the grounding is not safe or adequate."
Since the incident, the Contra Costa County Fire Protection District has appointed an inspector to begin investigating tank farms for code compliance and to determine where industry standards are lacking.
County officials are beginning to explore what steps are necessary to increase oversight to make fuel storage facilities safer.
“It comes down to fire inspectors, code developers and other industry representatives coming together and deciding what that standard is going to be, and who ultimately is going to be the authority,” said Randy Sawyer, the county’s chief environmental health and hazardous materials officer.
Officials were also concerned with the apparent lack of building plans and permits for several tanks at the site, including the two that were destroyed.
The Contra Costa County Conservation and Development Department said it found no records of plans or permits for an expansion of the site that was completed in 1991.
John Gioia, a member of the Contra Costa County Board of Supervisors, said homeowners in the county face a tougher permit and inspection process than the one in place for fuel storage facilities.
“There’s a reason that we require electrical permits on the construction of property,” Gioia said. "It should be no different with a highly explosive tank. To have an industry self-certify grounding, when we require homeowners get an inspector to make sure they’ve met all the electrical code, seems incongruous. For anyone out there that says, 'let’s have industry tell us what to do ...' No. We don’t have homeowners tell us how to ground. We inspect. How can we do otherwise in a large tank facility like this?”
Supervisor Federal Glover echoed his concern.
“There needs to be a regulatory body looking at this,” he said. “To not have regulatory guidance in a tank farm, we’re really missing the boat on that.”
County officials said further analysis of the report will take several months, and that another public meeting will be held to discuss further action.