Transient Arrested in 150-Acre Brush Fire : Thousand Oaks: The man is suspected of arson after parking a truck in grass, believed set ablaze by the exhaust system.

A 20-year-old transient has been arrested on suspicion of arson in connection with a fire that scorched 150 acres of brush-covered hills in Thousand Oaks, authorities said Thursday.

Billy Houser was booked into Ventura County Jail on Wednesday after he was found in the North Ranch neighborhood with the keys to a truck that was charred in the fire, Ventura County Sheriff’s Detective Dennis Reed said.

Fire investigators suspect that heat from the pickup’s exhaust system started the blaze.

Houser was initially jailed on suspicion of auto theft and suspicion of arson. He is being held in lieu of $10,000 bail.

Thursday, however, Reed said the 1991 Mazda pickup truck that was found in the fire was not stolen, as had been reported earlier.

Houser told police that he borrowed the truck from a friend and forgot to return it. He parked the truck beside Cresthaven Drive, and heat from the catalytic converter ignited grass beneath the vehicle, Fire Department spokesman Scott Quirarte said.

Houser is scheduled to be arraigned today. Reed said authorities have not determined whether to press felony or misdemeanor charges against Houser, since he apparently did not deliberately set the fire.

“He wasn’t malicious. He was just dumb,” Reed said. “A felony charge . . . just doesn’t make sense.”

Nearly 300 firefighters battled the fire for more than three hours as it moved toward North Ranch Village, a 120-unit condominium complex located north of Hillcrest Drive.

The fire was doused relatively quickly because firefighters were able to bulldoze a trench around it, but it could have been disastrous in a less accessible neighborhood, Assistant Chief David Festerling said.

“This is a much better place to have a fire than in Ventu Park,” he said, referring to a community in the hills south of the Ventura Freeway.

“On balance, if we had to have a fire, Ventu Park is the one place where we don’t want to have it,” Festerling said.

Many of the homes in that area were built before the county banned combustible wood shingles and required sprinklers to be installed in homes built in high fire-hazard areas.

Today, Ventu Park has about 200 houses, about 20 of them topped with wood shingles. Some homes are perched on steep, brush-covered hills that are accessible by only one road.

Festerling said the last fire in Ventu Park was in 1976. Sparked by a construction worker’s tool, it quickly spread into Hidden Valley south of Thousand Oaks before it was contained.

County fire prevention officer Ted Marsh said the Ventu Park area is plagued by narrow roads and inadequate water supplies for fire protection.

“When you get up to the upper elevations, they don’t have tanks high enough,” Marsh said. “It has the potential for being more hazardous. With that fire, it wouldn’t have stopped in Ventu Park.”

Lee Hill, Ventu Park homeowner and a county fire captain who spent six years at the station that protects Ventu Park, said he has been concerned about the combination of narrow roads, thick brush and combustible roofs for some time.

Hill said the brush in Ventu Park is much thicker and the hills much steeper than they are above the hills that burned in North Ranch.

“Ventu Park could be a disaster waiting to happen,” said Hill, who now works at a fire station in Somis. “Yesterday’s fire in Ventu Park, in the right location, might have gone all the way to the ocean.”