A raging fire that engulfed three truck tankers at a Northern California chemical plant Wednesday kept residents in about 2,500 homes indoors for several hours before firefighters extinguished the flames.

The intense three-alarm blaze caused no injuries but sent up thick black smoke and threatened several other tankers in the facility. Police said the plant itself did not burn.

Authorities evacuated everyone within a quarter-mile of the Ashland Distribution plant, located in an industrial area in this city of about 108,000 in Solano County, said Fairfield police Officer Cleo Mayoral.

Others within a one-mile radius of the plant were told to stay indoors after the blaze broke out just before 6 p.m. as authorities tried to determine whether the burning chemicals posed a health threat.

The chemicals were identified as ethyl acetate, a solvent used in nail polish remover, and toluene, used in paint and gasoline.

“It’s toxic at a certain level, but it’s not a poisonous gas that’s being released,” Mayoral said. “We haven’t had any reports of medical calls as a result of this.”

Firefighters surrounded the blaze to keep it from spreading but were initially forced to let the fire burn as the intense heat kept them away from the flames. Personnel arrived from nearby Travis Air Force Base to help battle the blaze, which was extinguished just before 9 p.m.

Authorities lifted the emergency order to remain indoors after the fire was out. Its cause was not yet known.

Ashland Distribution is a division of Ashland Inc., a global company based in Covington, Ky., that distributes chemicals to the automotive, appliance, personal care and other industries.

Damages from the blaze would likely amount to “tens of thousands of dollars,” said Ashland spokesman Jim Vitak.

The company expected the 30-employee Fairfield facility to be open for business Thursday, Vitak said.