The Diamond Shamrock Corp. Landfill sits on eight acres in Cedartown, Georgia. Waste oil and other byproducts from chemical manufacturing were disposed there in the late 1960s or 1970s. The EPA added the site to the National Priorities List (NPL) in 1990 because of groundwater contamination.
Four contaminants are present in the groundwater: 1,2-dichloroethane, manganese, toluene, and trichloroethene. EPA identified these because they pose an unacceptable risk to human health or the environment based on the amounts found, the potential for exposure, and known health effects.
The site's responsible party treated about 1,500 cubic yards of contaminated soil using bioremediation and incinerated about 8,400 gallons of liquid waste at a licensed facility. Remaining soils met cleanup standards for unrestricted use. The long-term remedy, in place since 1995, relies on institutional controls to prevent groundwater use and drilling, fencing and signage to restrict site access, and ongoing monitoring of ground and surface water. In 1997, EPA updated the manganese cleanup goal from 200 to 850 micrograms per liter, a change that did not alter the overall approach. An Explanation of Significant Differences was issued in December 2025 to document a significant change to the original remedy for Operable Unit 1.
Human exposure is currently under control, with no unacceptable exposure pathways identified. Groundwater migration is also under control, with contamination stabilized and no unacceptable discharge to surface water. Cleanup of manganese in groundwater is still ongoing. Residents and businesses use the public water system or wells unaffected by the remaining contamination. The site remains fenced and locked. A Five-Year Review was completed in 2021 confirming the remedy protects human health and the environment. Another Five-Year Review is currently underway, and the next one is estimated to conclude between August and October 2026.
Community members can stay involved through public notices, public meetings, and interviews that EPA conducts throughout the cleanup process. Site documents are available at the Cedartown Public Library at 245 East Ave., Cedartown, Georgia 30125. Two EPA contacts are available for questions about the site.
