Schofield Barracks is a 17,725-acre U.S. Army installation in Wahiawa, on the island of Oahu, Hawaii. Industrial operations contaminated the site with volatile organic compounds (VOCs), chemicals that evaporate easily and can move through soil into groundwater. The site was added to the Superfund National Priorities List (NPL) in August 1990 and was formally deleted from that list on August 10, 2000, after cleanup goals were met.
The two contaminants of concern are trichloroethene (TCE) and carbon tetrachloride. Both were found in groundwater. TCE in drinking water was the main driver for early action. In 1986, the Army installed a groundwater treatment system on four production wells to address that problem. The site was organized into four operable units (OUs), each targeting a different part of the problem. OU1 covered possible TCE sources, OU2 addressed groundwater using air stripping and pump-and-treat technology, OU3 covered basewide miscellaneous areas, and OU4 addressed the landfill. OU1 and OU3 required no further action. Records of Decision, the formal documents that lock in a cleanup plan, were issued for three of the four OUs between September 1996 and February 1997.
Contaminated soils were removed through excavation. The landfill received regrading and a vegetated cover. EPA selected "no further action" for non-TCE soils in 1996 after removal work eliminated the health threat. Construction of all remedies was completed in September 1998. Human exposure is currently under control, with no unacceptable exposure pathways identified across the site. Groundwater migration is also under control, with contamination stabilized in its original area and no unacceptable discharge to surface water. The site achieved "sitewide ready for anticipated reuse" status in June 2006, meaning all cleanup goals have been met and any required land-use controls are in place.
Long-term monitoring continues. Five-year reviews are conducted regularly to confirm the remedy stays protective of human health and the environment. The most recent review was completed in September 2022. Those reviews have consistently found that response actions comply with the selected remedy and remain protective in the short term. Continued coordination between responsible agencies is part of maintaining long-term protectiveness.
Community members with questions can contact the EPA Community Involvement Coordinator.
