More than 1,900 acres of the former Marine Corps Air Station El Toro in Irvine have been cleaned up and removed from the list of the nation's most hazardous sites after more than two decades, the U.S. Environmental Protection Agency announced Monday.
Officials say $165 million in soil removal and groundwater treatment by the U.S. Navy and local water agencies has cleaned up contamination at much of the old World War II-era air base, to the point that it no longer poses a risk to human health or the environment.
The removal of all but 600 acres of the El Toro site from the federal Superfund list, finalized last week, clears one obstacle to development of land set aside to build the Orange County Great Park and thousands of homes.
"It will allow us to move forward with development of the Great Park in an accelerated manner," said Jeff Lalloway, mayor pro tem of Irvine and chairman of the Great Park board of directors.
For more than a decade, Irvine has planned to transform about 1,300 acres of the old base into a sprawling public park surrounded by homes and businesses, though city leaders have seen a series of setbacks and have developed only about 230 acres of the park.
"Being able to remove the Superfund name removes a stigma and helps the community grow," said EPA Regional Administrator Jared Blumenfeld. "People should feel confident that they can play and recreate and use the land."
Built in 1942 to train pilots during World War II, El Toro was developed into a permanent base for jet fighters on the West Coast.
Investigations in the 1980s revealed contamination from decades of aircraft maintenance and repair, including soil laced with compounds known as polychlorinated biphenyls, or PCBs, and a plume of groundwater tainted with trichloroethylene and other hazardous compounds that migrated more than three miles from the base beneath the city of Irvine.
El Toro was named to the federal Superfund list in 1990.
After the base was decommissioned in 1999, the Navy auctioned off much of the property for $650 million through a 2005 deal with homebuilder Lennar Corp. that transferred about 1,300 acres in the middle of the base to the city of Irvine to build the Orange County Great Park.
The portion of the Superfund site that has been delisted includes 700 acres of city-owned land. The other 1,200 acres are being developed by the firm FivePoint Communities, which has an agreement with the city to build hundreds 688 acres of public parkland in exchange for the rights to construct up to 9,500 homes nearby.
"FivePoint is gratified that this major milestone has been completed in the process of returning the former land of El Toro to productive, public use," Chief Executive Emile Haddad said in a written statement.
Work to extract and treat groundwater and monitor capped landfills on the portion of the base that remains on the Superfund list is expected to take years and an additional $50 million, according to the EPA.
The groundwater is used for irrigation, but is not tapped for drinking water.