The U.S. Environmental Protection Agency has reached a $21 million settlement with Northrop Grumman Space & Mission Systems Corporation that requires Northrop Grumman to clean up groundwater contamination at the San Gabriel Valley Superfund Site in Southern California.
Northrop Grumman, representing 45 other settling defendants, will build a groundwater cleanup system that uses wells to pump out contaminated groundwater at the Puente Valley Operable Unit, preventing it from further migration. Northrop Grumman will also install water conveyance pipelines and construct a treatment plant to remove Volatile Organic Compound (VOC) contaminants from the groundwater. The treated water will be used for drinking water supply, water reclamation projects, or discharged to surface water.
The Puente Valley Operable Unit is an area of contaminated groundwater located beneath the City of Industry, the cities of La Puente and Walnut, and portions of unincorporated Los Angeles County. The groundwater was contaminated by more than 60 source properties that used VOCs for degreasing, metal cleaning, and other purposes.
There are 45 water suppliers in the San Gabriel Valley that use the San Gabriel basin groundwater aquifers to provide 90 percent of the drinking water for more than one million people.
Northrop Grumman has already spent more than $10 million implementing intermediate zone remedial action in compliance with an EPA order issued in March 2002. The settlement also provides for reimbursement of $465,420.90 to the EPA and $90,000 to the California Department of Toxic Substances for past costs.