Historical Petroleum Release at DPW Facility

SCOPE OF WORK: Release Abatement Measure and LSP Services

Historical Petroleum Release at DPW Facility

Historical Petroleum Release at DPW Facility_2

Historical Petroleum Release at DPW Facility_3
Omni Environmental Group provided Licensed Site Professional (LSP) services under a Release Abatement Measure (RAM) Plan following the identification of petroleum-contaminated soils (PCS) at a Department of Public Works. The PCS was identified during excavation activities to access the septic tank serving the DPW building. Given the presence of environmental contamination, all work was stopped, and the town notified its insurer, who subsequently requested that Omni Environmental Group conduct assessment and environmental due diligence activities.

A series of iterative assessment measures were conducted under our direction to define the extent of the release condition and develop a Conceptual Site Model. Through the performance of test pitting, soil boring installation, soil and wastewater sampling, and video inspection of subsurface septic system piping, our staff identified historical release conditions consisting of fuel oil, motor oil, and gasoline-impacted soils. These petroleum oils were released to historical subsurface drainage piping that was later connected to a septic tank. The PCS consisted of historical fill materials surrounding the exterior septic tank and interior drainage piping beneath the DPW building. We next coordinated with a professional engineer to prepare a structural excavation plan (SEP) and an environmental contractor to conduct the remedial actions.

LSP services have included:

  • Preparation and submission of a 120-day Release Notification Form, Health and Safety Plan, and Massachusetts Contingency Plan (MCP) regulatory submittals;
  • Supervision and direction of interior and exterior PCS excavation under the SEP and RAM Plan;
  • Elevational monitoring of the building during structural excavation activities, and
  • Coordination of PCS transport and off-site recycling.

Additionally, post-excavation soil samples were collected to document the effectiveness of the remedial measure, identify areas of residual impacts and support risk characterization under the MCP.

Omni Environmental Group is providing ongoing LSP services to perform necessary vapor intrusion assessment activities during the “heating season” to evaluate the potential for residual PCS to impact indoor air, as outlined under the MassDEP Vapor Intrusion Guidance. The expected outcome of LSP services is a RAM Completion supporting a Permanent Solution Statement for the Town DPW Site.