The Island Point Oil Site (the Site) is adjacent to the Androscoggin River in Lewiston, Maine and comprises a mix of publicly and privately owned properties on the Island Point Peninsula. The Site includes an approximate one acre parking lot adjacent to Veteran's Memorial Park (owned by the City of Lewiston), an approximate 300 foot portion of Mill Street (privately owned), and the Lewiston Stream Substation property (owned by Central Maine Power). The Columbia Mill was formerly located where the parking lot is now situated, the Libby Mill was formerly located just north of the parking lot and the Lewiston Stream Substation property, and the Lewiston Stream Substation property currently houses an active substation. Site history and previous environmental assessments indicate several former UST locations on the subject properties, which were utilized by the former mills and the substation primarily to store No. 6 oil.
The properties of concern are located on the Island Point Peninsula north of Main Street. The geographic coordinates of the approximate center of the areas of concern on the Site are:
The Site is bordered to the:
- North by privately owned properties including an active hydroelectric station;
- East by a parking lot and commercial building;
- South by Main Street and public works water pump station; and
- West by the Androscoggin River and portions of Veteran's Park.
In spring of 2012, the Maine Department of Environmental Protection (MEDEP) requested that EPA Region 1 Emergency Planning & Response Branch (EPRB) provide assistance evaluating the extent of subsurface oil contamination at the Site. In the summer of 2011, the MEDEP initially responded to a report of an oil sheen on the Androscoggin River just downstream from Great Falls. MEDEP observed an oil discharge that appeared to be emanating from a retaining wall that separated the parking lot (adjacent to Veteran's Park) from the river. After the initial discovery, MEDEP contractors deployed boom around the discharge location.
With boom in place, MEDEP conducted boring and test-pit investigations over the summer and fall of 2011 in cooperation with the City of Lewiston and Central Maine Power (CMP). Investigation efforts focused on the parking lot and on the CMP property in an effort to locate and characterize subsurface oil contamination. Test-pits were excavated on the east side of the parking lot where 10,000 and 12,000 gallon underground storage tanks (USTs) were previously located. Test-pits were also excavated on the CMP property in the vicinity of a 147,000 gallon cement UST that was abandoned in place sometime in the 1970's. Soil borings were advanced primarily in the parking lot area in the vicinity of the oil discharge location down gradient from and in between the river and the former UST locations. During test-pit excavations, approximately 280 tons of oil-saturated soil and 381 gallons of an oil-water mix was removed from the area around the former USTs on the east side of the parking lot. Black oil was observed emanating from a pipe that protruded from a retaining wall separating the former Columbia Mill property from the former Libbey Mill property. The cap from this previously sealed pipe was removed and approximately 15 to 20 gallons of black oil was recovered and transported for off-site disposal.
Two bedrock monitoring wells were installed in an effort to determine whether No. 6 oil had migrated into the bedrock. Oil was observed during installation of the bedrock well located near the 147,000 gallon UST, but not in the bedrock well located just east of the parking lot. MEDEP installed a series of monitoring wells in the fall and inspected them in December of 2011. Inspection results did not indicate the presence of oil in the monitoring wells.
An additional potential source of discharging oil is a feeder pipe that allegedly runs under Mill Street (between the CMP property and the parking lot. The feeder pipe is reported to have supplied the mill complex with No. 6 oil delivered via rail car from just south of Main Street. The feeder pipe and the conditions under Mill Street between the CMP property and the parking lot could not be investigated in 2011 due to safety concerns presented by the underground high voltage lines coming from the substation and lack of access permission from the Mill Street owner.