To address groudwater contamination in the shallow and intermediate water-bearing zones within the "mouth-of-the-valley" area, EPA is using three separate groundwater extraction and treatment systems to prevent the migration of contaminated groundwater and protect water supply aquifers..
| City | La Puente |
|---|---|
| County | Los Angeles County |
| State | California |
| Coordinates | 34.01667, -117.95830 |
San Gabriel Valley Area 4 is a federal Superfund site in California. The Superfund program, created by Congress in 1980, addresses sites where hazardous substances have been released or threaten release into the environment. EPA scores potential sites using the Hazard Ranking System; those that score high enough are placed on the National Priorities List.
Current status: Cleanup underway. Active cleanup is underway, meaning EPA has approved a remediation plan and work is in progress. Cleanup timelines vary widely — some sites take decades depending on contamination depth, groundwater involvement, and funding availability.
EPA has identified 4 contaminants of concern at this site, including 1,4-dioxane, chromium(vi), n-nitrosodimethylamine. Contamination has been detected in groundwater.
If you live near this site and have health concerns, your state health department can provide site-specific guidance. EPA maintains a community involvement program for most NPL sites, and site documents — including the Record of Decision, five-year reviews, and public health assessments — are typically available through EPA's Superfund site profile.