| Site Type: Long Term/National Priorities List (NPL) |
WEST SITE/HOWS CORNERS
Map this site in Cleanups in My Community
| Plymouth,  Maine|
| Penobscot County
| Street Address: ||CAMBELL/SAWYER ROAD |
| Zip Code: || 04969 |
| Congressional |
| EPA ID #: ||MED985466168 |
| Site ID #: ||0101800 |
| Site Aliases: |
| Site Responsibility: ||Potentially Responsible Parties |
| NPL LISTING HISTORY |
| Proposed Date ||02/13/1995|
| Final Date ||09/29/1995 |
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The West Site/Hows Corners Superfund Site is defined as a 17-acre parcel of land owned by George West and the surrounding properties where groundwater contamination has come to be located. Mr. West used a small, 2-acre portion of the site to operate a waste oil facility from 1965 to 1980 in affiliation with the Portland/Bangor Waste Oil Company (PBWO). This 2-acre portion of the site is fenced and is referred to as the source area. The source consists of a partially grassy clearing, approximately 150 by 200 feet, with occasional bedrock outcroppings that run north-south. There are no buildings or other structures within this area. Waste oil, delivered by PBWO tank trucks, was stored within the source area in approximately eight 1,000 to 20,000 gallon storage tanks. PBWO collected, transported, and deposited unknown quantities of waste oil from military bases, auto dealerships, municipalities, local garages, bulk transportation companies, industries, and utility companies. Oil was stored in tanks; the company then sold the lighter oil for fuel and the heavier oils for dust control on dirt roads. PBWO company records indicate that the waste stored on the site was predominantly composed of used motor oils and industrial lubricating oil; however, because of the varied types of facilities contributing waste, the exact elements of the oils are unknown. In 1980, PBWO ceased operations at the site and PBWO cut up the tanks on site and sold them to a scrap metal dealer. No waste oil activities are known to have take place after the tanks were removed. When MEDEP performed a routine site inspection in 1988, the only waste source was contaminated soil. This soil was subsequently removed in 1990-1991 as part of an initial cleanup action. In addition, EPA installed an alternate water supply system in 1993-1994 to provide a permanent supply of safe drinking water to those residences whose private water supplies have been contaminated by past site activities.
Threats and Contaminants
Groundwater in abandoned private supply wells near the source area and in monitoring wells located throughout the site are contaminated with polychlorinated biphenyls (PCBs), and volatile organic compounds (VOCs) including tetrachloroethene, trichloroethene, and dichloroethene. While no one is currently being exposed to contaminated groundwater, continued use of existing private wells or the installation of new private wells could result in people being exposed to unsafe levels of contamination at some time in the future.
This site is being addressed in three stages: initial actions, non-source area groundwater cleanup (Operable Unit 1), and source area groundwater cleanup (Operable Unit 2).
Response Action Status
|Initial Action ||Aboveground storage tanks were removed in 1980 after PBWO ceased operations at the site. The site is surrounded by a chain link fence which was partially installed by the Maine Department of Environmental Protection in 1988 and completed by EPA in 1990. From 1990-1991, EPA removed approximately 850 tons of contaminated soil from the center of the site and disposed of it at a federally-approved toxic waste facility. An alternate water line was installed in 1993-1994 for residents with or determined to be at risk of having contaminated groundwater. |
|Remedial Action for Operable Unit 1 ||Under the oversight of EPA, the potentially responsible parties completed an investigation of the nature and extent of contamination at the Site. Data from this investigation was used to develop both a Human Health and Ecological Risk Assessment. Based on the findings of these assessments, EPA identified the need for cleanup actions to address groundwater contaminated by past site activities. Consequently, the potentially responsible parties completed a Feasibility Study (FS) in July 2002 to evaluate cleanup options for Non-Source Area groundwater. Cleanup options for Source Area groundwater will be evaluated in a separate FS which will be completed as part of Operable Unit 2. |
In September 2002, EPA issued a Record of Decision for Operable Unit 1 that selected containment of the highly contaminated groundwater; monitored natural attenuation of the groundwater in OU1; long-term monitoring of the groundwater, surface water; and sediments in nearby ponds; and institutional controls.
|Remedial Action for Operable Unit 2 ||EPA issued a Record of Decision for the Source Area (OU2) in September 2006. This followed an evaluation assessing the technical practicability of restoring the source area groundwater to drinking water quality. This assessment concluded that it was technically impracticable to restore the source area groundwater. Therefore the 2006 Record of Decision included a waiver for restoring the groundwater within a limited area of the Site while affirming that with containment of the highly contaminated groundwater by pumping, that monitored natural attenuation of OU2 groundwater was a viable approach.|
In addition to the groundwater, the 2006 Record of Decision required the investigation and mitigation, if determined necessary, of the vapor intrusion pathway from the source area into indoor air in the surrounding homes.
|Entire Site ||In 2003, the Town of Plymouth created a zoning ordinance for the area around the Hows Corner Site that prevents the use of groundwater. This control has been supplemented by the placement of restrictive covenants on nearly all the properties within the zone through agreements between the individual property owners and the Potentially Responsible Parties. |
|Entire Site ||Following negotiations for remedial design and remedial action, with approximately one hundred Potentially Responsible Parties that concluded with a consent decree being entered into US District Court in Maine. |
|Five Year Reviewsl ||Five Year Reviews were conducted in 2008 and 2013. The most recent review concluded that the remedy continues to be protective of human health and the environment, however, in order for the remedy to be fully protective in the long term, all properties located within the institutional control zone must have fully executed and recorded restrictive covenants. |
Removing aboveground storage tanks and contaminated soil and erecting a chain link fence have reduced the potential for further contamination and potential exposure at the West Site/Hows Corners Superfund Site. However, as presented in the Remedial Investigation Report (July 2001), groundwater underlying the Site poses an unacceptable risk to human health and the environment. The Potentially Responsible Parties completed a Feasibility Study in July 2002 to assess various cleanup options to address contaminated groundwater.
In 2002, EPA issued a Record of Decision for Operable Unit 1 that selected containment of the highly contaminated groundwater; monitored natural attenuation of the groundwater in OU1; long-term monitoring of the groundwater, surface water; and sediments in nearby ponds; and institutional controls. In 2006, EPA issued a Record of Decision for Operable Unit 2 (Source Area) including a technical impracticability waiver to restore the source area groundwater within a limited area of the Site while affirming that with containment of the highly contaminated groundwater by pumping, that monitored natural attenuation of OU2 groundwater was a viable approach. The 2006 Record of Decision also required the investigation and mitigation, if determined necessary, of the vapor intrusion pathway from the source area into indoor air in the surrounding homes.
After EPA signed a second Record of Decision in September 2006, negotiations were conducted with approximately one hundred Potentially Responsible Parties (PRPs) for the remedial design and remedial action (RD/RA), The negotiations concluded with a consent decree being entered into US District Court in Maine in February 2010. Two of the Potentially Responsible Parties signed the consent decree as Performing Settling Defendants who will fund and perform all cleanup activities associated with the Site. The other Potentially Responsible Parties also signed the consent decree as cash-out parties, but not as performing parties.
Design of the groundwater containment system was completed in October 2007. Construction of the groundwater containment system began in 2010 and was substantially completed by late 2011. The groundwater hydraulic containment system includes a bedrock well that pumps the contaminated groundwater up through an aboveground treatment system consisting of an ion exchange to remove metals, liquid phase carbon adsorption to remove contaminants of concern, and four wells that inject the clean water back into bedrock. The system was designated Operation & Functional by EPA in 2012.
EPA also conducted preliminary investigations in 2007 and 2010 to evaluate the potential vapor intrusion pathway into surrounding homes. The Performing Settling Defendants performed additional investigations in 2010-2013 and installed vapor mitigation systems at two residences in 2011 and 2013 respectively.
Current Site Status
Operation of the groundwater containment system continues, along with long-term monitoring and ongoing optimization of the system as appropriate. Monitoring and maintenance of the vapor intrusion mitigation systems will continue. The Performing Settling Defendants continue to pursue implementation of restrictive covenants at all properties within the institutional control zone.
Links to Other Site Information
Newsletters & Press Releases:
Federal Register Notices:
Reports and Studies:
Plymouth Town Hall, Route 7, Plymouth, ME 09969 207-257-4646
OSRR Records and Information Center, 1st Floor, 5 Post Office Square, Suite 100 (HSC), Boston, MA 02109-3912 (617) 918-1440
|EPA Remedial Project Manager: ||Kevin Heine |
|Address: ||US Environmental Protection Agency|
5 Post Office Sq., Suite 100
Mail Code OSRR07-1
Boston, MA 02109 - 3912
|Phone #: ||617-918-1321 |
|E-Mail Address: ||firstname.lastname@example.org |
|EPA Community Involvement Coordinator: ||Pamela Harting-Barrat |
|Address: ||US Environmental Protection Agency|
5 Post Office Sq., Suite 100
Mail Code ORA20-1
Boston, MA 02109 - 3912
|Phone #: ||617-918-1318 |
|E-Mail Address: ||email@example.com |
|State Agency Contact: ||Rebecca Hewett |
|Address: ||Maine Department of Environmental Protection|
State House Station #17
Augusta, ME 04333-0017
|Phone #: ||207-287-8554 |
|E-Mail Address: ||Rebecca.L.Hewett@maine.gov |