State and federal officials announced Friday a potentially historic agreement to remove all radioactive contamination from a partial nuclear meltdown in 1959 at a rocket testing site just outside Los Angeles.

Residents who have fought for years for the cleanup heralded the agreement signed by the Department of Energy, NASA and state officials. The agreement must still go through a public review process.

The decades-old site is known as the Santa Susana Field Laboratory and is now largely owned by Boeing Co.

Boeing said in a statement that it had only just learned of the agreement and was reviewing it.

Proponents of the deal said it would require a high-level cleanup in the most polluted parts of the site.

"It's more than we'd hoped for a long time," said Marie Mason, the head of a four-member homeowner's association who are all sick with leukemia, breast cancer or serious thyroid conditions. "We are thrilled."

During the Cold War, the Atomic Energy Commission used what was then Rocketdyne's 2,850-acre Santa Susana site in hill country west of the San Fernando Valley to test rockets and experimental nuclear reactors. One of the reactors, which had no containment dome to prevent radiation from leaking into the environment, experienced a partial meltdown in 1959.

There were other problems over the years, including two more accidents, burn pits with radioactive contaminants and a rocket fuel explosion that killed two scientists and resulted in a $650 million fine after Rocketdyne illegally disposed of the hazardous waste. Cleaning solvent used to wash down test stands tainted some groundwater.

As the decades passed, critics complained about the slow pace of the cleanup.

"At one point the Department of Energy announced to us that they were going to leave 98 percent of all the contaminated soil there and that they were also willing to release the site for residential use," said former state Sen. Sheila Kuehl of Santa Monica, who spent years pushing for strict cleanup legislation. "There were scientists saying you get more radiation from a banana peel than you would from this site."

Boeing, which purchased the Rocketdyne site in 1996, has disputed this. The company has said it has spent millions of dollars already and has worked with state regulators to resolve a complex situation.