After knowing about the problem since the mid-1990s, the Consumer Product Safety Commission, the independent federal agency charged with warning consumers about defective products, has issued a warning about faulty attic furnaces made by Consolidated Industries.

The warning was released late Wednesday--the same day The Times broke the story that hundreds of thousands of unsuspecting homeowners statewide may have the furnaces, which fire inspectors say caused scores of fires in California over the last decade. The furnaces were installed from 1984 to 1992 under at least 30 brand names.

The CPSC said it didn't issue the warning sooner because federal law prohibits it from issuing warnings while it's conducting recall negotiations. Federal investigators hoped to recall faulty Consolidated furnaces, but were unable to do so when the Indiana-based company went out of business.

The Consolidated furnaces fail because of alterations that Consolidated made to comply with regional air quality standards, federal safety experts found.

After it broke the story, The Times received a call from a Laguna Hills family who said contractors told them deadly carbon monoxide would have leaked into their home if they hadn't had their Consolidated furnace removed.

Other consumers called for information on a class-action lawsuit filed by California homeowners against Consolidated in 1994. Plaintiffs' attorneys are scheduled to ask a Santa Clara Superior Court to set a trial date for the case next month.

Residents in housing tracts from Glendora to Newport Beach called contractors and safety experts and asked for help inspecting their furnaces in response to the story. Contractors from Walnut to the San Fernando Valley to Orange said they fielded numerous calls from anxious furnace owners.

John Kopp, a contractor at Ocean Air Conditioning & Heating Co. in Laguna Niguel, said he took a half-dozen Consolidated-related calls and talked to others in the business whose "phones were ringing off the hook."

The CPSC warning says the furnaces "present a substantial risk of fire." The warning adds that there are about 190,000 Consolidated units in California, 60,000 fewer than the 250,000 units that CPSC investigators reported to The Times last week.

Southern California fire investigators disputed the number of fires listed in the warning, which said the CPSC had about 30 reports of fire and damage to homes in the state.

"They've done no investigation as far as going out and finding fires," said Mike Freige, a senior fire inspector in Torrance. "I've found 18 on my own and I know there are more out there." To date, no one has tried to catalog the total number of fires in the state caused by the furnaces.

The warning suggests that residents who have Consolidated furnaces call a licensed heating contractor, who must take apart the furnace and inspect the burner and heat exchanger for damage.

Safety experts questioned a suggestion in the warning that the Consolidated furnaces can be repaired.