California and the West : Tire Fire Spews Hazardous Smoke : Pollution: Mammoth dump catches fire in northern San Joaquin Valley. Residents are warned to stay indoors.

A bulging mountain of scrap tires six stories high caught fire in the northern San Joaquin Valley early Wednesday, spewing a black plume of smoke 3,000 feet in the air and sprinkling soot for miles.

Favorable winds initially blew clouds of the noxious smoke away from populated areas. But a wind shift was expected, and Stanislaus County officials--declaring a local state of emergency--warned residents to prepare to evacuate or remain inside their homes with the windows closed.

“There’s this huge black cloud and it’s casting a shadow over the whole town,” said Laura Deimler, a waitress in Westley, a small farming settlement five miles from the fire at California’s largest tire pile. “It’s ugly.”

Because tire fires are nearly impossible to put out, the blaze is expected to burn for months. A smaller mound of tires to the north in Tracy caught fire more than a year ago and still smolders today.

“We consider this an environmental disaster,” said Roland Brooks of the San Joaquin Valley Air Pollution Control District. “It’s just a real mess.”

Tire fires are the dangerous legacy of America’s appetite for automobiles. Millions of scrap tires are scattered illegally in canyons, quarries and fields throughout the state, and California produces 30 million more a year--the most of any state.

In 1989, the state launched a war on illegal tire piles, many of which are “orphan” piles with no responsible party to pay for cleanup. Since then, authorities have made a dent in the state’s stockpile of discarded tires, but about 15 million remain and the threat of fires persists.

Wednesday’s blaze is raging in a small ravine just west of Interstate 5 in farm country two hours south of Sacramento. Officials believe that it was sparked by lightning from a thunderstorm just before dawn.

By dusk, the fire had engulfed 80% of the pile’s 7 million tires. Crews in bulldozers attempted to carve off chunks of the burning mound but intense heat forced them to abandon the effort.

The fire’s proximity to Interstate 5 spawned concerns that smoke could affect visibility on the state’s major north-south freeway. No immediate traffic problems were reported, but authorities were poised to close the interstate if needed.

In terms of weather, the dramatic fire could not have struck at a better time. Normally, winds in the area blow in a south-southeasterly direction--which would put Westley, Patterson and a few other small settlements in the path of the black plume.

But Wednesday, a frontal system pushed winds to the west, into deserted dry foothills that separate the San Joaquin Valley from the Santa Clara Valley. The intense heat of the fire also had a beneficial effect--forcing the plume up high and aiding dispersion.

“The big fear is we’ll get stagnant air conditions with smoke near ground level,” said Brooks. He said state air quality experts from Sacramento had set up portable monitoring stations near the fire and in adjacent towns.

The greatest risk to those inhaling the smoke comes from particulate matter as well as hydrocarbons and some trace elements of hazardous materials, such as benzene, health authorities said.

Aside from the potential respiratory problems, tire fires can contaminate ground water. Burning tires emit an oil that seeps through soil and into the aquifer, said Steve Rosenbaum of the state Regional Water Quality Control Board.

Although the California Aqueduct--which serves Southern California--passes about one mile from the fire site, Rosenbaum said it was unlikely that soot falling into the water would contaminate the supply.

State regulators said they have been troubled by the Stanislaus County pile for years, both because of its size and the lack of fire prevention measures in place.

The mound sits on a 40-acre parcel owned by Edward Filbin who, in the 1950s, opened the disposal site that at one point mushroomed to include 40 million tires. The tires were supposed to be recycled, either in an adjacent incinerator that produces energy or through other market uses.

Instead, regulators say, the pile kept growing, prompting the state to revoke the operation’s permit last year and issue a cleanup and abatement order in July.

Filbin, who has contested the order, could not be reached for comment. His San Francisco attorney, Thomas Trapp, did not return a telephone call from The Times.

State regulators blamed the blaze on Filbin’s failure to guard against the threat of fire. He should have created firebreaks within the pile and had fire suppression equipment on hand, they say.

Legislation signed by Gov. Gray Davis this year will help the board in its battle against illegal tire piles, Chandler said. The bill, by Sen. Debra Bowen (D-Marina del Rey), gives state inspectors authority to enter private property where tires are stored if they suspect a threat to the public health or environment.