The McKin Co. site covers 7 acres in Gray, Maine, and operated as a liquid waste storage and disposal plant from 1965 to 1978. It handled up to 200,000 gallons of waste per year, including solvents, oils, and industrial chemicals. The site was added to the EPA's National Priorities List (NPL) in 1983 and was deleted from that list in 2022 after cleanup goals were achieved.
EPA identified 43 contaminants of concern across soil, groundwater, surface water, and solid waste. Chlorinated solvents are a key concern, including trichloroethene, tetrachloroethene, vinyl chloride, and 1,1,1-trichloroethane. Soil also contains polycyclic aromatic hydrocarbons (PAHs), phthalates, phenolic compounds, and aromatic chemicals like toluene and ethylbenzene. Contaminated groundwater reached private wells by 1977, but all affected residents were connected to the public water supply in 1978 and currently face no known exposure to contaminated groundwater.
Cleanup was organized into two operable units (OUs), which are distinct zones with specific cleanup plans. Onsite work included soil aeration that treated 12,000 cubic yards of contaminated soil by mid-1987. A groundwater extraction and treatment system followed in 1990. Because fully restoring the groundwater proved technically impracticable, EPA shifted strategy in 2001 toward long-term monitoring, natural attenuation, and institutional controls. Those controls include a town ordinance banning groundwater use in a designated zone, restrictive covenants on 21 properties, and conservation easements protecting nearby waterways. An engineered cover protects contaminated water at Boiling Springs. The Royal River has met applicable water quality standards since 2009. Contaminant levels in groundwater continue to decrease.
The site reached a milestone called "sitewide ready for anticipated reuse" on September 30, 2013, meaning all cleanup goals were met and land-use controls were in place. Physical construction of cleanup work is complete. Human exposure is under control, and contaminated groundwater migration has stabilized. EPA and the State of Maine determined that no further Superfund-financed cleanup is needed, though site deletion does not prevent EPA from acting again if future conditions require it.
Five-Year Reviews are conducted regularly to confirm that past cleanup work stays protective of public health. The most recent review was completed on July 18, 2023, and the next is estimated between July and September 2028. Institutional controls remain in effect and will stay so as long as contamination or cleanup components are present on site. Community members with questions can reach out to EPA's Community Involvement Coordinator or Remedial Project Manager listed in the site contacts, or contact the Maine Department of Environmental Protection.
