- Photos: Blaze erupts in Diamond Bar
- Interactive map: Diamond Bar brush fire
- Traffic map: 60 Fwy in Diamond Bar
The fire scorched about 50 acres.
The Los Angeles County Fire Department says the blaze had as many as eight start points.
Police believe a vehicle's malfunctioning catalytic converter, part of the exhaust system, was the apparent cause. The device can spit out hot metal that would account for the multiple ignition points, according to fire officials.
The driver of the Ford pickup truck was not aware of the fire and he continued to drive. He was later detained on the freeway by Ontario police, questioned and released. He's not considered a suspect because police are calling the fire accidental.
Crews attacked the fire from the air and on the ground. About 150 firefighters were on scene at its height to protect homes. Helicopters and SuperScooper airplanes also dropped loads of water on the flames in the hilly terrain.
The L.A. County Sheriff's Department reports no structures were destroyed.
Dozens of homes were threatened and hundreds of Diamond Ranch High School students were in lockdown as the flames curled around the school.
A spokesperson for the Pomona Unified School District said the school was not threatened and students were not evacuated. The students were safely sheltered in the gym and later released to go home.
"It kind of caught us by surprise, like, we didn't really think, cuz we were at lunch at the time. And we heard the fire alarm and we looked down at the lower field, and there was a lot of smoke so it was pretty shocking," said Ramon Gonzales, a sophomore at Diamond Ranch High School.
Ramon ran away from the threatened school against the orders of administrators, but his mom says he made the right decision.
"I told him to run. He was seeing the flames, so I told him to run. They were trying to stop him, but I told him to run," said Darla Gonzales, Ramon's mother.
Four students suffered minor injuries from smoke inhalation. However, L.A. County Fire says at no time were the students in serious danger.
"There was great clearance here at the school, there's no brush really close to the facilities or structures here at the school. So they were not ever in immediate danger," said Los Angeles County Fire Capt. Mark Savage.
There were no evacuations or injuries.
Freeway traffic slowed to a crawl as smoke blanketed the area.