The gas-fired furnaces were installed in about 190,000 California homes built from 1983 to 1994. All were manufactured by Indiana-based Consolidated Industries, formerly Premier Furnace, but were sold under many brand names, including Amana, Sears, Bard, Coleman, Kenmore and Heatmaster.

The furnaces have been tied to at least 31 fires, but no deaths or serious injuries. Fires have been reported throughout Orange County, including Irvine, Yorba Linda, Coto de Caza, Foothill Ranch and Laguna Niguel.

"I grabbed a ladder, opened the door to the attic, and the flames were four feet high," said Cliff Gish of Yorba Linda, whose attic burned in December 1997. "Luckily it was on a Saturday morning, and we were home or we would have lost everything."

After Gish's fire, word spread quickly. Fire inspectors and gas-company employees canvassed the neighborhood, warning homeowners about the potential danger and inspecting scores of furnaces.

The U.S. Consumer Product Safety Commission has known for years that the heaters were faulty, but didn't issue the warning until Wednesday.

"That's disgusting," said Patti Pattiman of Coto de Caza, who had smoke billowing from her heater last year. "How many homes have burned while they waited?"

John Kopp agrees. He's president of Ocean Air Conditioning and Heating Co. in Laguna Niguel and has been trying to alert authorities about the hazardous heaters for years. The heaters also spew out high amounts of deadly carbon monoxide.

"What they did was really lax," Kopp said. "I think they jeopardized the public safety the whole time."

The commission defends its actions. "This is such a complicated case," said CPSC spokesman Ken Giles. "As with any recall or with any hazardous product, we wanted to negotiate some kind of repair, replacement or refund with the company. That's normal.''

But the negotiations dragged on for years, complicated by class-action lawsuits. Before any remedy could be found, the company went out of business, filed for bankruptcy and liquidated its assets.

Irvine was one of the cities that notified its residents of the danger. After a furnace fire in a house in Woodbridge last November, the city mailed a letter to homeowners warning of "serious health and/or fire hazards," and urged them to have the furnaces inspected immediately.

In Yorba Linda, city officials issued 264 permits for replacement furnaces, mostly in the East Lake Village area, officials said.

Forensic engineer Gerald Zamiski, president of Vollmer-Gray Engineering Laboratories Inc. in Long Beach, began examining the defective furnaces in 1990 for clients who had fires.

He has been an expert witness in various lawsuits against Consolidated, and in 1997 he analyzed 100 failed furnaces for the CPSC.

There are two main problems with the furnaces, according to Zamiski. First, a coating designed for high temperature resistance on the burner was damaged during the manufacturing process . Second, rods added to the furnaces to meet California's stringent air-quality standards actually radiated heat to the damaged coating and the heat exchanger. Over time, the heat exchanger cracks, and air pushes large flames out of the furnace.

"I've never heard of another furnace with this type of failure," Zamiski said.

How long the furnace lasts before it fails depends on how much it is used. Generally, in Northern California, heaters break down faster because the weather is cooler, Zamiski said. Problems often develop after three to 10 years.

Two fires caused by the faulty furnaces in San Jose prompted attorney Rob MacDonald to file a lawsuit against Consolidated in 1994, which grew into a class-action case. MacDonald, who has worked closely with the CPSC, currently represents all furnace owners in California who are not represented by other attorneys. Although Consolidated filed for bankruptcy and shut down operations early this year, MacDonald hopes to recover damages from the company's insurer.

While he knows of 31 fires that have been caused by the furnaces throughout California, there's no way to uncover every attic fire in the state and determine if it was caused by a Consolidated furnace, he said. Instead, he has to rely on fire departments and gas companies to notice a pattern.

Denise King, a spokeswoman for the Southern California Gas Co., said the utility learned of faulty furnaces in 1995 from South Bay fire departments. The company then alerted its service crew, who now shut off any Consolidated furnaces that are dangerous. If an inspection shows the furnace has not begun to deteriorate, employees warn the customer about potential problems and advise annual exams.

Although King said the utility prefers consumers hire a licensed heating contractor to inspect suspect furnaces, the gas company checks if asked. One of California's largest homebuilders, J.F. Shea Co., will send notices to residents in 100 communities it built throughout California, including Orange County. If residents have the faulty heater, it will be repaired or replaced, and the cost will be borne by Shea and its insurance company.

Consolidated's attorneys did not return phone calls Wednesday. But Trane, which sold about 7,000 of the heaters in California, said it's concerned about safety and wants to do the right thing, said attorney Jeff Bleich. Sears, which sold about 200 of the furnaces, "will take care of the Sears customers," said spokeswoman Peggy Palter..

Register staff writers Nick Harder and John McDonald and news researchers Eugene Balk, Dick Glasow and Sharon Clairemont contributed to this report.