The former Commonwealth Gas property, located at 350 Irving Street in South Framingham, Massachusetts, consists of approximately 22 acres of uplands and wetlands. A majority of the uplands is occupied by several commercial businesses associated with the storage and sale of landscaping materials, automobile storage, firewood cutting/storage, and heavy equipment storage.
Located in a mixed-use area, the property is bordered by wetlands, Beaver Dam Brook, and commercial and residential properties. An unnamed stream flows north through wetlands along the eastern edge of the property and discharges to Beaver Dam Brook. The Sudbury Aqueduct, an emergency back-up water supply system owned by the Commonwealth of Massachusetts and operated by the Massachusetts Water Resources Authority, bisects the Site from roughly west to east. An active natural gas pipeline is located on the southern half of the property.
Historical Site Usage
The Site is a former manufactured gas plant (MGP) that produced gaseous hydrocarbon fuel from a combination of coal, coke, and oil feedstock from the late 1880’s until approximately 1967. Tar processing facilities, which recycled some of the MGP by-products, also operated at the Site from at least the 1920’s to the 1960’s. Prior to development as an MGP, the Site was primarily wetlands. As was common practice before passage of the Wetlands Protection Act, a majority of the wetlands at the Site were filled with wastes and other materials as the MGP and tar processing facilities expanded.
The surrounding environment was polluted from leaks and spills associated with the former processing equipment/piping, and during the routine handling of raw materials and process residuals. While such practices are not allowed today, liquid wastes were discharged directly to the environment via settling and spray ponds located on the property, as well as to the wetlands and the unnamed stream on the eastern side of the property. Although a majority of the facility was dismantled in 1967, portions of former structures such as below-ground foundations, process equipment, and piping were never removed.
Testing conducted by Eversource between 2006 and 2009 detected the presence of petroleum and coal tar constituents, including cyanide (historically used to purify the manufactured gas prior to distribution), in soil, groundwater, wetlands sediments, and surface water. Coal tar, light oils, and/or tar-water mixtures were present in groundwater monitoring wells, test pits, and wetlands areas. Sediments containing coal tar constituents were also detected within Beaver Dam Brook at least 1,500 feet downstream of the former gas plant. In addition, inspections conducted by the Massachusetts Water Resources Authority indicated the past infiltration of coal tar and coal tar constituents into the Sudbury Aqueduct.
Between 2010 and 2011, Eversource excavated 2,400 tons of coal tar-laden sediments from the unnamed stream to the north of the Sudbury Aqueduct and 177 tons of soil from two locations to the south of the aqueduct where elevated concentrations of cyanide were detected in shallow soils. In June 2011, Eversource submitted a Temporary Solution Statement to MassDEP, indicating that although contamination remained, commercial workers, customers, and trespassers could safely use the property.
In September 2014, MassDEP notified Eversource of its intent to audit the Temporary Solution Statement submitted for the Site. In June 2015, MassDEP issued a Notice of Audit Findings/Notice of Noncompliance, determining that the extent of contamination had not been adequately defined, sources of contamination had not been fully contained or controlled, migration pathways had not been adequately assessed, and more data was needed to support the conclusions of the risk assessments. As a result of the Audit, MassDEP invalidated the Temporary Solution Statement for the Site and set deadlines for additional work to be conducted.
In July 2015, Eversource submitted a work plan for additional testing at the Site. Following a meeting with MassDEP representatives, Eversource submitted a revised work plan, which was conditionally approved by MassDEP on September 23, 2015.
Additional Assessment Activities/Next Steps
On September 28-29, 2015, Eversource began the additional required testing activities by collecting samples within the mulch storage yard of Landscape Depot, a tenant at the Site, and digging test pits in the area of the Sudbury Aqueduct and the Former Open Tar Well near the property entrance on Irving Street. More comprehensive soil, groundwater, surface water, and sediment testing is planned to complete the required Site-wide supplemental assessment by the September 2016 deadline set by MassDEP.
By November 23, 2015, Eversource will begin further testing in the wetlands on the southeast portion of the Site to better determine the extent of contamination beyond their property line in this area. Results are expected before the end of the year.
Eversource has notified MassDEP of its intention to excavate coal tar-laden soil and waste debris from the Former Open Tar Well during the winter of 2015-2016. Eversource has also indicated its intent to conduct further removal of coal tar wastes within the southern wetland, and to address the coal tar in shallow soils on the southern portion of the Site as part of future response actions.
In addition, Eversource has posted “No Trespassing” signs to warn any trespassers that the property is a Disposal Site regulated by MassDEP.