San German Ground Water Contamination

Overview

A contaminated groundwater plume sits beneath San German, Puerto Rico, traced to the Retiro Industrial Park about half a mile southeast of three public water supply wells. The U.S. EPA (Environmental Protection Agency) added the site to the Superfund National Priorities List (NPL) in March 2008. The NPL is the federal list of the most serious hazardous waste sites in the country.

The contamination involves five volatile organic compounds (VOCs), a group of chemicals that evaporate easily and can move through soil and water. The main chemicals are tetrachloroethylene (PCE) and trichloroethylene (TCE), both used in degreasing and dry cleaning. The other three are breakdown products of those solvents: vinyl chloride, 1,1-dichloroethene, and cis-1,2-dichloroethene. All five have been found in soil, groundwater, surface water, and sediment. The three contaminated public wells once served about 2,280 people, but the Puerto Rico Aqueduct and Sewer Authority closed all three by early 2006.

Cleanup is organized into two operable units (OUs), which are separate phases of work. OU1 covers contaminated soils and shallow groundwater near the Wallace and CCL lots. The EPA finalized the soil cleanup plan in December 2015, and remedial design wrapped up in July 2023. Soil cleanup work is estimated to run from September to November 2027 and will use methods like soil vapor extraction, engineered caps, and bioremediation. A removal action at the site was completed earlier, in September 2015. OU2 covers the broader groundwater plume. The EPA selected that cleanup plan in September 2019, with remedial design starting in January 2020. The groundwater remedy includes monitored natural attenuation, anaerobic bioremediation, institutional controls, and ongoing groundwater and indoor air monitoring. In January 2024, the EPA directed potentially responsible parties to begin cleanup design and remedial action for the first phase.

Human exposure is currently under control, meaning no unacceptable exposure pathways have been identified at this time. However, groundwater migration is not yet under control, and physical construction of the cleanup is not complete across the entire site. VOC vapors from soil can move into nearby buildings through a process called vapor intrusion. To address this concern, contractors will place summa canisters inside selected homes and buildings to test indoor air. The EPA plans to visit the San German community in 2026 to share information about that testing.

One business is currently operating on the site, employing 39 people. Community members with questions can contact the EPA's Community Involvement Coordinator. Site documents are available at San German City Hall and at the EPA's Caribbean Environmental Protection Division office in Guaynabo, Puerto Rico.