Flames clouded two ethanol holding tanks on Tuesday at a NuStar Energy petrochemical storage facility around San Francisco, prompting health departments to urge residents of two adjacent cities to remain indoors for much of the day while crews struggled to subdue the blaze.
No injuries had been reported from the fire, which began shortly before 2 p.m. and spread to a vast grassy field right outside the tank farm in the waterfront network of Crockett, California, about 30 miles northeast of San Francisco.
Local media reported a blast that shook buildings and rattled windows for miles around and sent a fireball into the air. Some residents thought it was an earthquake.
The fire was declared contained by 9 p.m., fire officers wrote on Twitter, however, they had been still working to prevent it from affecting other tanks.
Initial reports that flames had spread to a third tank proved false, Contra Costa County Fire Division spokesperson, Steve Hill, told reporters at a news conference. He stated the grass fires scorched about 15 acres around the facility before they were extinguished.
One of the two burning storage tanks fell from the blaze, spilling some of its contents into a secondary containment region and raising the risk of flames spreading to nearby constructions, Hill said.