Background

The Waste Site Cleanup Program is administered by the Commonwealth of Massachusetts to streamline and facilitate cleanup of releases of oil and hazardous material to the environment. The regulations for the assessment and cleanup of oil and hazardous material releases are known as the Massachusetts Contingency Plan ("MCP", 310 CMR 40.0000). The MCP establishes Soil and Groundwater Categories based upon the potential exposures which may result from the presence of oil or hazardous material in these commonly contaminated media. In December 2019, the MCP was revised to include notification requirements and cleanup standards for PFAS (Per- and polyfluoroalkyl substance) compounds in soil and groundwater media.

The assessment and cleanup of a release site is managed by a "Licensed Site Professional", or "LSP" to make sure that the actions are performed in accordance with M.G.L. c.21E, the MCP and the Department's standards. The use of LSPs allows assessments and cleanups to proceed at most sites without delays due to the need to get MassDEP approvals. An overview of the MCP process is available from the MassDEP’s website.

MassDEP Findings

On March 27, 2025, the Town received Verdantas’ Field Investigation and Data Analysis Summary from MassDEP. The purpose of this report is to summarize the limited subsurface investigation and associated activities conducted between November 2024 and January 2025. This investigation was focused on identifying the presence and extent of PFAS at the Fairgrounds campus. Based on the site investigation performed, Verdantas offers the following conclusions (refer to page 13 of the report):

• The laboratory analytical results of soil samples collected indicate that PFAS6 concentrations are relatively low and are distributed relatively evenly across surficial soil at the Site and surrounding town-owned properties with no indication of a PFAS source at the surface. Furthermore, there is no evidence indicating that soil near the water table is impacted with PFAS at the locations investigated.
• The highest concentration of PFAS6 at 22.33 ng/L was detected in the groundwater sample collected from monitoring well VDT-4FG-4, which is located on the Site(4 Fairgrounds Road) and is directly behind the Nantucket Public Safety Complex building to the east. The next highest concentrations were detected at monitoring wells VDT-WAITT-12 and VDT-2FG-5 which are both located on Town-owned properties and on the Site (2 Fairgrounds Road), respectively.
• Concentrations of PFAS6 were not detected in groundwater samples collected from monitoring wells located furthest to the west and southwest of the Site.
• There does not appear to be a correlation between the concentrations of PFAS6 detected in soil samples and groundwater samples. PFOA and PFOS were detected in both soil and groundwater samples. However, the concentrations of PFOA and PFOS detected in soil samples were relatively lower than the concentrations detected in groundwater samples.
• Select non-regulated PFAS substances were detected in groundwater samples, including PFBS, PFBA, PFHxA, and PFPeA. Non-regulated PFAS substances were not detected in soil samples.
• A minimal hydraulic gradient was observed based on the results of this investigation; however, the groundwater elevation data indicates that the groundwater flow is in a northerly direction, towards Old South Road.

Town Review and Findings

Additionally, the Town, with assistance from a contract with TRC, completed a voluntary review of data collected at the Fairgrounds Campus and the surrounding area from MassDEP’s investigation (RTN 4-0029612). That report found the following:

• No significant PFAS source area was identified by the MassDEP SARSS Investigation by Verdantas.
• Sampling of the geothermal sell system on the 4 Fairgrounds Road property did not detect PFAS.
• Forensics source evaluation based on Private Well Sampling results by TRC suggests at least two distinct PFAS sources in the immediate vicinity of Toms Way
  • Northern Toms Way source appears older based on PFAS constituents
    • Suggests a significant source with a prevalence of PFHxS
    • Possibly associated with alkaline surfactants, specialty cleaners, potentially replacement AFFF or carpet cleaning residuals (older homes)
  • Southern Toms Way Source appears Younger Based on PFAS Constituents
    • Characterized by generally mobile PFAS (e.g., PFBS, PFOA) indicative of a continuing source
    • Possibly associated with clothes washing or carpet cleaning residuals (newer homes)

2 Fairgrounds Road Property

The Town of Nantucket purchased the 2 Fairgrounds Road property from the Nantucket Electric Co. in 2004, after approval of Article 77 at the 2004 Annual Town Meeting.

• Title: Purchase of Nantucket Electric Co.’s property at 2 Fairgrounds Road
• Details: 19.9 acres
• Cost: $15.5 million Proposition 2 ½ debt exclusion
• Approval: Approved 353-7