3 Blazes Prompt Fireplace Warning : Safety: Officials are worried that thousands of homes with prefabricated metal fireplaces might have hazardous chimney caps.

Three recent house fires in Moorpark have prompted an investigation by a fireplace manufacturer and city and Ventura County officials who are concerned that thousands of area homes with prefabricated metal fireplaces might have hazardous chimney caps.

An investigator for the Ventura County Fire Department said Monday that thousands of homes countywide may be affected by shrouds placed over the tops of chimneys to camouflage spark arresters and termination caps.

“We want to warn everyone in the county,” said William Hager, county fire investigator.

A spokesman for Fireplace Manufacturers of Santa Ana, one maker of the prefabricated fireplaces used by many builders, said he is reluctant to agree with the estimate of the number of homes involved until the houses in three Moorpark subdivisions are inspected more closely.

Flyers are to be distributed this week in the Glenhaven, Marlborough and Pacifica tracts in Moorpark--where the fires occurred last month--as well as the Peach Hill area, where many houses that may have prefabricated metal fireplaces have been built recently.

The three subdivisions where the fires occurred have about 250 houses, and Peach Hill includes about 3,000 homes, said Patrick Richards, director of community development for Moorpark. Several builders and fireplace manufacturers are involved, he said.

The flyers will warn homeowners not to use such fireplaces--if there is a metal shroud atop the chimney--until the shrouds are examined and, if necessary, replaced, said Hager and Joseph Coscione, chief engineer and vice president of Fireplace Manufacturers.

Coscione’s company is one of several makers of prefabricated metal fireplace liners, popular because they are designed to be installed directly on house floors as a unit, including the flue and chimney liner.

Hager and Coscione blamed the fires on metal shrouds placed atop chimneys. The shrouds are not part of the prefabricated fireplace system but appear to have been added by builders to make chimneys more attractive, they said. In some cases, they added, the shrouds are covered by paint or stucco.

Coscione said the shrouds are not authorized by his company, were not included in the manufacturer’s instructions and parts and should not have been used.

Moorpark’s chief building and safety official could not be reached for comment.

Richards said building inspectors usually do not closely inspect prefabricated fireplaces because they pass extensive tests before approval.

Under some circumstances, the metal covers can force heat and soot back into the chimneys, drying and charring the outer wood framing over time and making them more flammable, Hager and Coscione said.

No one was injured in the Moorpark fires, which occurred Dec. 19, 29 and 30.

Three similar fires in Camarillo last year led to replacement of chimney covers on about 300 homes, Hager said. He said the use of the decorative covers seems to be relatively recent and unique to California--possibly, he said, “because Californians are more style-conscious.”