Brush fires caused by sparks from its diesel particulate filters and expensive recalls have apparently caused Cleaire, Inc., a California specialty manufacturer, to suddenly shut down.

Without a public announcement, the company, based in San Leandro with a manufacturing operation in San Diego, ceased operations and pulled down its website last Friday. Cleaire is owned by NewWorld Capital Group, a private equity firm that invests in firms engaged in environmental mitigation.

Owners of trucks equipped with Cleaire filters are left without warranty support, but will be given exemptions from enforcement by Californias Air Resources Board, which had mandated a DPF retrofitting program for older diesel-powered trucks and buses.

"ARB is committed to ensuring that these impacts are minimized and wishes to make it clear that affected owners and fleets with Cleaire filters, as noted in ARB records, will not be penalized for missing deadlines with applicable ARB regulations until this situation is resolved," the agency said in a statement on Monday.

Fleet owners who have devices from other manufacturers will not be affected by Cleaire's closure, and will continue to be subject to applicable regulations.

"ARB is working closely with Cleaire distributors, installers, and other authorized representatives to meet the current challenge, and to make sure that affected fleets have alternative compliance options if replacement parts are unavailable," the Board says.

Fires Related to the Filter

The sparking and fire-starting was linked to a metal substrate in Cleaire's LongMile filters. A recall subsequent to a September 2011 fire in Washington State had the company replacing them with another type of filter.

Washington officials blamed the 3,500-acre Monastery Fire in 2011 on a Cleaire filter aboard a truck. A smaller fire in August 2012 had a similar cause. The larger fire caused $5.4 million in damage by destroying 29 residences and 71 other buildings, news reports said. It took 721 firefighters 11 days to extinguish the blaze.

A CARB investigation into the Monastery Fire found that the root cause was turbocharger failure on the trucks engine that sent oil into the DPF and set it on fire. Flaming particles then left the truck's tailpipe and ignited dry grass along Highway 97 near Goldendale, Wash.

Following the fire, a school district in Humboldt, Calif., pulled from service 17 buses that were fitted with LongMile DPFs because they feared catastrophic system failure, said a newspaper report at the time.

Established to serve CARB-mandated demand for exhaust aftertreatment devices, Cleaire and other companies designed and made retrofittable DPFs to keep otherwise dirty trucks in service.

A Cleaire LongMile filter reportedly cost $20,000, including installation. CARB used state and federal money to pay for some installations, but many other California truck owners had to pay for installations and bitterly criticized the CARB regulations.

"We now have technology and all it does it set forest fires," Hank De Carbonel of the California Concrete Pumpers Alliance told a Bay Area news organization after the Washington fire. "In our case were talking about a real risk of life and limb because of their mandates when they know nothing about their industry that theyre trying to regulate," he said of CARB officials.

To assist fleets affected by the companys dissolution, ARB has posted a letter to Cleaire customers with helpful information. According to ARB, the letter contains guidance for affected fleets regarding Cleaire retrofit devices that have been installed on vehicles and equipment operating in California.

The ARB letter is available here