A four-alarm blaze that destroyed 250 vehicles at a Brentwood auto dismantler and forced the evacuation of 50 people began as a grass fire on Ortiz Court, a fire official said Tuesday.

“The cause is still undetermined, but the origin was a grass fire on Ortiz Court,” said Acting Chief Hugh Henderson of the East Contra Costa Fire Protection District. “It spread to (an unoccupied) mobile home and then into the wrecking yard.”

Henderson said the fire destroyed about 250 vehicles at Continental Auto Recyclers on Brentwood Boulevard, just east of the court. An undetermined number of outbuildings were also lost, but the main office building for Continental was not burned. As of Tuesday morning, an investigation of the incident had fixed no estimate on damages.

A mobile home and residence on the fire’s south flank were saved, Henderson said. On the north side, a fence surrounding a motor home storage facility was burned, but the motor homes were not harmed.

“We built a box around (the fire) early on, and we stuck real hard to keep the fire in there,” Henderson said. “I think we did an excellent job on the fire, and it was an excellent example of good cooperation between agencies.”

About 70 firefighters from ECCFPD, Contra Costa’s Con Fire and CalFire were involved, as was the state Office of Emergency Services and police from Brentwood, Oakley, the Contra Costa County Sheriff’s Office and the CHP.

It took about two hours to completely contain the blaze, which involved dozens of explosions and a thick column of black smoke visible for miles. In addition to the evacuations, about 150 people were told to shelter in place as a precaution. No injuries were reported.

For the original story and photos on the fire, click here.