Fire Races Over Chino Hills Park : Conflagration: A youth playing with a model rocket triggered the blaze. About half of the park was burned.

A rapidly moving brush fire, started by a 15-year-old boy setting off a model rocket, raced through the tinder-dry Chino Hills State Park on Thursday, burning at least 5,000 acres but causing no serious injuries or loss of buildings, officials said.

The fire, which sent up a huge plume of smoke that could be seen for miles, was burning fiercely along brushy hills on the Orange-San Bernardino County line early today, but firefighters predicted that it would be contained by mid-morning.

The Yorba Linda teen-ager who accidentally started the fire was playing with a model rocket launcher in the park near his home, fire officials said. The youth, who was not identified because he is a minor, was arrested near the fire scene. He had tried to put out the fire himself and had called the 911 emergency number to report it, authorities said. He was released to his parents after being charged with a misdemeanor.

“He’s admitted to starting it,” said Orange County Fire Department Capt. Dan Young.

Young said the boy suffered minor burns as he attempted to put out the blaze, but did not require hospitalization. Four prison inmates also received minor injuries while helping to battle the inferno, Young said.

The boy will be charged with the misdemeanor offense of “recklessly starting a fire,” according to Orange County Fire Department Investigator John McMasters.

McMasters said the boy “was very cooperative and very apologetic.”

According to fire investigators, the blaze started about 12:40 p.m. at the south border of the park near the intersection of Blue Gum Drive and Rim Crest Drive, in the north-central part of Yorba Linda.

The blaze raced into the state park, less than a block away, and quickly moved northeasterly toward the San Bernardino County line, adjacent to the Carbon Canyon area, scene of a major brush fire two weeks ago.

The Carbon Canyon fire started about 11 a.m. June 27 and consumed 6,600 acres in Orange and San Bernardino counties. Police arrested a transient, Peter Diaz Reyes, 29, and charged him with starting the blaze.

The burned-over land in the Carbon Canyon area served as a buffer and kept the new fire from spreading there, fire officials said.

“There’s not a lot of fuel left (in the Carbon Canyon area) because of the last fire,” Young noted.

No evacuations were ordered as the brush fire spread, but some dairy cattle in the hills had to be moved to safer areas.

The fire, which spread quickly because of the dry, brittle grassland in Chino Hills State Park, literally ignited in waves.

“We had one fire engine that was driving along at 25 m.p.h., and the fire kept up with it,” Young said.

Chino Hills State Park encompasses about 10,000 acres, and most of the burned land was within that area. Fire ignited several aged sycamores in the park, and they glowed Thursday night like eerie jack-o-lanterns as the blaze consumed the insides of the trees.

Late Thursday night, the fire came within a quarter of a mile of the Butterfield Ranch subdivision in San Bernardino County. Residents of the unincorporated community poured out into the streets to watch the fire raging on hills close to their homes.

San Bernardino County Supervisor Larry Walker, who was at Butterfield Ranch, said: “We’re lucky with this one. It seems to have gone through without endangering anyone. But the sad thing is that Chino Hills State Park is in really bad shape.”

Although no structures were reported lost in the state park, some wooden signs were damaged. Walker said that although a lot of the park vegetation looked devastated, much “is chaparral, which cleans itself out in a fire, and it’ll come back to life within a couple of years.”

Loss of the 40- to 50-year-old trees was a more severe blow, however.

The brush fire came within a mile of the Olinda Village area of Brea during the afternoon. The village also had been threatened by the Carbon Canyon fire, prompting some residents of the area to remark that the fires are virtually inevitable.

More than 500 firefighters and a wide range of equipment, including airplanes and helicopters dropping anti-fire chemicals, worked in 90-plus-degree temperatures to try to halt the blaze.

Traci Roach, 25, stood in a subdivision street holding her 6-month-old daughter while her husband, Dale, 25, videotaped the fire raging in the nearby hills.

“The firefighters say it’s going the other way so I’m not that worried, but at 5 o’clock I came out here and it was all over those hills all of a sudden,” Traci said. “I couldn’t believe it. It’s really scary.”

Martha Schildknecht, 62, who also lives in Butterfield Ranch, stood in front of her home, staring at the hills. “It scares me when I see the fire so close,” she said. “I wonder if we should get our things and get out of here, but the firemen say we should be OK.”

* SWELTER CONTINUES: School schedules are modified. Fairgoers are undiscouraged.B9

Times staff writers Bill Billiter and Davan Maharaj contributed to this report.