A storage tank exploded at a solar power plant Friday, sending flames and billows of smoke into the sky for hours and forcing authorities to evacuate the immediate area.

The fire, which broke out about 6 p.m., was still burning four hours later at the SEGS II power plant near Interstate 40 about seven miles east of Barstow, said San Bernardino County Fire Battalion Chief David McLees.

Firefighters “tried to put water on it and said it was like putting out a house fire with a garden hose,” he said.

The 900,000-gallon tank was holding a heat-transfer fluid called therminol, McLees said. Therminol is a hydraulic fluid that is heated to about 850 degrees and run through pipes to solar panels to help generate electricity, McLees said.


The fluid can be mildly toxic. Authorities were also trying to keep flames from leaping to two adjacent containers that held sulfuric acid and caustic soda, both toxic substances, he said.

An unspecified number of employees at the plant were evacuated. All known employees were accounted for, he said.

The cause of the blast was not known, McLees said.

Police and fire officials evacuated a half-square-mile area around the facility, said sheriff’s spokeswoman Sue Santana.