The West Site/Hows Corners is a 17-acre former waste oil facility in Plymouth, Maine. The Portland/Bangor Waste Oil Company collected and stored waste oil from military bases, auto dealerships, and municipalities there from 1965 to 1980. When operations stopped, the storage tanks were scrapped and left behind a contamination problem that spread well beyond the original 2-acre source area. EPA placed the site on the National Priorities List in September 1995.
Groundwater is the primary concern. EPA has identified 26 contaminants of concern, including chlorinated solvents such as trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane, plus benzene, arsenic, manganese, and polychlorinated biphenyls (Aroclor 1260). Some contaminants affect the entire site, while others are concentrated in the source area groundwater.
Cleanup has moved through several phases. Workers removed about 850 tons of contaminated soil in 1990 and 1991. An alternate water line was installed for affected residents between 1993 and 1994. A groundwater containment system was built and has been operating since 2012, pumping contaminated water through an aboveground treatment process and returning clean water to the bedrock. In 2006, EPA determined that fully restoring the source area groundwater to drinking water quality was not technically possible, so the strategy shifted to containment and monitored natural attenuation. The site is divided into two operable units. Operable Unit 1 covers the whole site and uses extraction wells, carbon adsorption treatment, reinjection of treated water, and institutional controls. Operable Unit 2 focuses on source area groundwater and relies on monitored natural attenuation. The company and other potentially responsible parties carry out these actions under EPA and Maine Department of Environmental Protection oversight.
Currently, no one is being exposed to contaminated groundwater. Private supply wells exist nearby, but a 2003 Town of Plymouth zoning ordinance prohibits groundwater use in the surrounding area, and restrictive covenants cover nearly all properties within that zone. Physical construction is complete and the site achieved sitewide ready for anticipated reuse in September 2013. EPA and state agencies continue monitoring groundwater, surface water, and sediments. The most recent five-year review was completed on September 28, 2023. The site has not yet been deleted from the National Priorities List.
Community members with questions can contact EPA's Community Involvement Coordinator or the Remedial Project Manager. For state-level information, contact the Maine Department of Environmental Protection. Public records are available at Plymouth Town Hall and at the EPA Region 1 records center in Boston.
