Defense contractor Northrop Grumman Corp. has agreed to spend $21 million to clean up polluted groundwater in the San Gabriel Valley.
Under a consent decree settlement announced last week by the U.S. Environmental Protection Agency, the company will pump contaminated water from beneath Industry, La Puente and Walnut; build pipelines; and construct and operate a treatment plant.
The area is one of four federal Superfund sites in the San Gabriel Valley, where more than 30 square miles of the water table are polluted with solvents and degreasing agents used for decades by business and industry.
The pollution, first detected in 1979, has affected the primary source of water for more than 1 million valley residents, forcing the closure of wells and spawning a long cleanup battle.
The settlement stems from an earlier cleanup order directed at TRW Inc., which had several facilities in the valley. The company was acquired by Northrop Grumman in 2002.
A Northrop spokesman said the corporation had no comment.
The EPA found 62 properties that were a source of contamination at the Superfund site. The owners of most of those sites previously settled with the EPA. A number of remaining firms reached an agreement with Northrop, which will treat water drawn from the intermediate groundwater zone.
The decree lasts for a decade, after which the EPA will issue a final cleanup order, agency attorney Dustin Minor said.