Deer roam in the shadows of hulking metal skeletons once used as rocket engine test stands, cleaned with chemicals now believed dangerous to people.

Nearly 70 bird species live in an area where a nuclear reactor partially melted down.

Groves of coastal live oak, southern willow scrub and native grasses cover the 2,850 acres of the hilltop Santa Susana Field Laboratory, where toxic chemicals were burned in an open air pit.

The laboratory, plagued with chemical and radioactive contamination from decades as a rocket engine and nuclear test site, is also a place of immense natural beauty.

The acreage may become parkland once it is cleaned, as part of a complicated deal between its owner, Boeing Co., and state regulatory agencies. The deal would require Boeing to clean the site to "levels acceptable for residential use and that protect individuals living in the vicinity of the property."

Open-space advocates say it would be an important addition to the inventory of preserved land stretching from Santa Clarita to Malibu. At the same time, some residents question if the public will be able to use the land with confidence after it is cleaned up.

"It's a critical link, really in terms of linkages," said Joe Edmiston, the executive director of the Santa Monica Mountain Conservancy. "If we can add it we'll have hard-wired a wildlife corridor and hiking corridor that's 40 miles."

The Field Laboratory was once like a town, with roads snaking around the property and clusters of buildings, some of which have been removed as part of the decade-long cleanup effort at the site. Edmiston envisions camping on the site and maybe an education center for schoolchildren or nature center in the areas where buildings once stood.

"It's really kind of a blessing," he said. "I would like to see most of it kept as open space."

Cameron Smyth's vision for the land is maintaining it as natural open space.

"I don't envision it becoming soccer fields or gymnasiums and softball fields," the Republican assemblyman from Santa Clarita said.

Joint powers legislation

While the land's future as parkland is still tentative, Smyth has readied legislation for introduction next season that would create a State Park Joint Powers Authority.

Members of the JPA would include the state parks department, Santa Monica Mountains Conservancy, the cities of Simi Valley and Los Angeles, and Ventura and Los Angeles counties. The group would be responsible for developing boundaries for the new park. It would also work to include properties adjacent to the Boeing land as part of the park.

NASA owns about 450 acres of the Field Laboratory. If it is decided the land is no longer needed, it will be turned over to the U.S. General Services Agency for disposal.

As part of the tentative agreement between Boeing Co. and the state, the aerospace company will "facilitate a no-cost acquisition of the NASA property," so it, too, can be preserved as open space.

Land would be released for public use in phases after it is cleaned and the California Department of Toxic Substances Control signs off. Some short-term work will be completed by 2017, while a long-term work schedule needs to be in place by that year, a DTSC spokeswoman said.

Money also will be needed to get the joint powers authority up and running. Smyth said he is working with the state Finance Department to get funds earmarked for the effort in the coming budget. He said it would be challenging because of the state's projected budget shortfalls, but he was hopeful there would be bipartisan support for the JPA.

Mary Wiesbrock, the executive director of Save Open Space, described the Santa Susana Field Laboratory property as a major corridor for wildlife traversing the region. The Agoura Hills resident is a veteran of battles to preserve open space, having played a key role in protecting from development Ahmanson Ranch in Las Virgenes Canyon. But as pleased as Wiesbrock is about the potential for more open space, she is leery about the land's safety.

"It's beautiful open space," she said. "It just needs to be cleaned up properly."

She is not alone.

Dennis Lane of Thousand Oaks is skeptical about the Field Laboratory's future as a park.

"From what I know about the contaminants there, I think I'd stay away from it," he said.

Boeing's commitment to turn the site over to the state once it is cleaned is contingent on the passage of legislation next year that would void portions of a bill signed into law last month. The law prohibits the transfer or sale of the Field Laboratory until the state toxics department certifies it has been cleaned to stringent standards reserved for federal Superfund sites.

But instead of using Superfund standard requirements, Boeing would clean the site to a standard acceptable for suburban residential use. The specifics of the cleanup levels will be part of a binding agreement among Boeing, the California Environmental Protection Agency and the state Resources Agency.

DTSC is tasked with overseeing the cleanup of chemical contaminants, and that would not change under the forthcoming agreement. However, the department also would become responsible for signing off on the cleanup of radiological contamination.

Residential standard cleanup

Jim Pappas, DTSC's project manager for the Field Laboratory, said the department would coordinate with EPA to ensure both the chemical and radiological contamination are cleaned to a suburban residential standard, which is more stringent than what is acceptable for open space.

Smyth and Edmiston said they had confidence in the level of cleanup that will be demanded and closely scrutinized by the public.

"There is no park professional that is going to put a campground or anything on a place that isn't clean," Edmiston said, adding the cleanup would likely take years. "We have no motivation to want to put anybody in harm's way."

If the transformation of the Santa Susana Field Laboratory comes to pass, it would not be the first Cold War era facility to undergo such a change. In Colorado, parts of Rocky Flats, a nuclear weaponry facility, have become a National Wildlife Refuge. There is currently no money to open the former Superfund site to the public. That's fine with watchdogs such as LeRoy Moore.

"In my view, it's essentially a local hazard forever because of the long half life of plutonium," said Moore, a consultant with the Rocky Mountain Peace and Justice Center. "I don't think anyone should go there."

The site was cleaned up to a range of risk that is less stringent than that proposed for the Santa Susana Field Lab.

Steve Berendzen, the refuge manager with U.S. Fish and Wildlife Service, said the agency hopes to put in trails that would connect the Field Lab property to nearby established trails.

In Simi Valley, Diane Bentz, of Save Open Space Santa Susana Mountains, said she would feel confident using the Field Laboratory as a place for recreation.

Bentz wouldn't want to live there, she said, but "would I want to go there and hike with my family? Yes I would."