After years of community demand for proper cleanup, the U.S. Environmental Protection Agency is recommending the Santa Susana Field Laboratory be added to its Superfund cleanup list for federal oversight.

The agency studied the site at least twice before and failed to add the former rocket engine test site, known as Rocketdyne, to the list. But a third study completed last week, which examined the entire site, led the EPA to recommend the 2,850-acre property two miles south of Simi Valley be added to its national cleanup priority list.

The decision was made in part because of a lack of consistent cleanup authority over the various segments of the site.

"There was not a lot of significant effort of cleanup between the multiple federal agencies and private companies," said Mike Montgomery, branch chief for the Superfund program.

Last week, the agency sent a letter to Gov. Arnold Schwarzenegger detailing the EPA's findings. The letter included the site's background and history with chemical contamination of on-site soil and groundwater. EPA officials estimate there are 500,000 gallons of tichloroethylene, a toxic chemical, lying beneath the site.

The agency is requesting the governor respond within 30 days. The EPA's objective is to propose the site be listed by early next year, Montgomery said.

Once it becomes a Superfund site, the EPA will become the lead agency overseeing all cleanup at the laboratory, which has been determined to be polluted with both chemical and radioactive contamination. The site is primarily owned by Boeing Co., with about 450 acres owned by NASA.

Currently, the U.S. Department of Energy is in charge of radioactive contamination. The DOE and its predecessors conducted nuclear experiments at the site. California's Department of Toxic Substances Control oversees the cleanup of chemical pollution at the Field Laboratory.

"The Superfund designation would deal with the whole site under one authority, and they would have to do consistent work under that authority," Montgomery said.

The EPA has assessed small parts of the site at the facility twice, and twice determined it did not qualify. The second assessment was in 2003, the same year the Energy Department backed out of a 1995 agreement that called for it to follow EPA guidelines for cleaning up the site.

But subsequent information prompted the EPA to take a harder look, said Dawn Richmond, the national Superfund list coordinator.

"We've studied it more than two times, never looked at the entire site," Richmond said. "It is routine to look at things more than once, as new concerns are raised from the community."

This year the Legislature approved SB990, a bill drafted by Sen. Sheila Kuehl, D-Santa Monica, which requires Boeing enter into a binding agreement with the state that the land to be cleaned to "levels acceptable for residential use."

"I think it's totally appropriate. It should be a Superfund site, we've been discussing this for years," Kuehl said.

She said that after the EPA previously did not qualify the Field Lab as a Superfund site, the community asked the EPA to revisit and to take into account the chemical materials on the entire site, not just radioactivity.

Community members have long called for the lab to be listed as a Superfund site, which would put in motion a stringent set of cleanup standards under EPA's leadership.

Dan Hirsch, co-founder of the nuclear watchdog group Committee to Bridge the Gap, is pleased with the EPA's decision.

"For 20 years the community has asked why the site has not been a Superfund site," Hirsch said. "If the governor concurs, it is likely it will be a Superfund site."

Holly Huff is a 35-year resident of Black Canyon Road, which leads to the former Rocketdyne site, and is glad the state has finally recognized what she and her neighbors always knew.

"It's got to be cleaned up to the state levels, I would think they wouldn't be accepting minimal standards when they could get better," Huff said.

Blythe Jameson, spokeswoman for Boeing, said the company didn't anticipate that much change as far as the cleanup was concerned. Jameson said Boeing has been cleaning the site since the 1980s.

"We've been working under the oversight of Department of Toxic Substances Control for many years."