Homes to Be Tested for Toxic Gas : Environment: The EPA will check for carcinogenic vinyl chloride in 200 Montebello residences near a landfill.

The U.S. Environmental Protection Agency announced Thursday that it will soon test about 200 homes in Montebello to determine whether a cancer-causing gas is seeping into them from a nearby landfill.

EPA spokesman Dave Schmidt said the agency already has detected “very low levels” of vinyl chloride, a known human carcinogen, over the dump owned by Operating Industries Inc., located in Monterey Park and bordering a Montebello residential neighborhood.

Fearful that the gas may be seeping underground into the foundations of the nearby homes, EPA officials will begin going door to door in the neighborhood today to advise residents that they will test for vinyl chloride in their homes starting Nov. 9.

“Nobody has reported any ill effects from these gases,” Schmidt said. “If they had, we would have been looking for them a lot sooner.”

He said the agency decided to investigate the insides of homes as a precaution after finding the gas in the outside air. If found in homes in amounts that exceed outdoor levels, the EPA will install a pipe and fan device to suck it out of foundations, Schmidt said.

“There is a possibility it might be there,” he said. “But we don’t expect to find high levels.”

The EPA will pay for the removal of the gas.

Operating Industries Inc., a federal Superfund site, accepted industrial, residential and commercial waste from 1948 to 1984, when it shut down, and liquid hazardous wastes from 1976 to 1983.

Schmidt said the EPA also will test homes for methane, which is potentially explosive. He said the homes were checked for methane in the mid-1980s, and dangerous levels were not found then. As a permanent measure that will be completed within four years, the landfill will be capped and a gas control system installed to prevent leaks. Currently, there are gas extraction wells on the periphery of the landfill to limit the emissions.

Vinyl chloride is a breakdown byproduct of trichloroethylene, a solvent used to clean metals, and perchloroethylene, a solvent for cleaning metals and clothes. Schmidt said they may have been dumped into the landfill during its operation.

If significant levels are found within many of the 200 homes, additional dwellings will be tested. “I’m sure we will if a lot of the homes have it,” the EPA spokesman said.