A brush fire broke out near the Rio Hondo River in Montebello on Sunday afternoon and grew to 200 acres by evening, closing roads, prompting evacuations at a nearby park and scorching an oil field.
At Whittier Narrows Recreation Area, the Legg Lake and shooting range areas of the park were evacuated, the Los Angeles County Sheriff's Department said.
A homeless man was arrested on suspicion of setting the fire, authorities said Sunday evening.
"We don't know if it was malicious intent or just a reckless fire," said Lt. Michael Bergman of the Montebello Police Department.
All eastbound lanes of the 60 Freeway were shut at San Gabriel Boulevard for hours, but the roadway reopened by 8:30 p.m., according to the California Highway Patrol. The San Gabriel Boulevard offramp remains closed.
There are also street closures on San Gabriel Boulevard, Rosemead Boulevard and Durfee Avenue, said Los Angeles County sheriff's Deputy Amber Smith. The Montebello Police Department said Lincoln Avenue was closed between Rea Drive and San Gabriel Boulevard.
Dan Amador, deputy chief of the Montebello Fire Department, said the fast-moving fire, which was reported about 1:15 p.m., jumped across Lincoln Avenue and spread into the Montebello Hills and onto the nearby PXP oil field.
"All oil field operations have ceased," Amador said Sunday afternoon. "Everything is shut down." The flames had also jumped across San Gabriel Boulevard into a bamboo field, he said.
Dark plumes of smoke were visible across the area as the fire raged.
Amador said in the evening that the fire, fueled by vegetation, had burned roughly 200 acres -- 50 of them within city limits -- and was 20% contained.
The fire is bounded by Rosemead Boulevard to the east and San Gabriel and Paramount boulevards to the west, and it has not crossed the 60 Freeway to the north, Amador said.
Several fire departments rushed to assist the Montebello Fire Department, including the Los Angeles County Fire Department and teams of firefighters from the cities of Pasadena, Monterey Park, San Gabriel, Alhambra, Arcadia, Glendale, South Pasadena and Monrovia.
No structures have been harmed, Amador said.
Residents have not been ordered to leave their homes, but a message was sent out "letting people know to be prepared to evacuate … if the situation warrants," said Leslie Luke of the county Office of Emergency Management.
"If they take it upon themselves to go ahead and evacuate, that's great," he said.
In the evening, the L.A. County Fire Department said a helicopter it sent to battle the blaze "had a hard landing," but "all crew members on board are OK."
Amador said Sunday evening that three firefighters have been injured in the course of their work. One had neck and back injuries associated with the helicopter's hard landing, he said. There was also a firefighter who suffered heat exhaustion and one who injured a shoulder.