Residential Insurance Claim

SCOPE OF WORK: Site assessment, LSP services, and site remediation in a residential setting

A release of #2 fuel oil occurred from an aboveground storage tank (AST) located in the basement of a home due to an improperly seated gasket on the AST supply line filter housing. Omni Environmental Group was retained by the fuel oil dealer’s insurance company to provide Licensed Site Professional (LSP) services, remedial oversight and direction, and to achieve regulatory closure. The release was reported to the Massachusetts Department of Environmental Protection (MassDEP) and was managed as an Immediate Response Action Plan under the Massachusetts Contingency Plan (MCP).

Excavation activities were conducted within the basement using a soil vacuum truck to remove contaminated soil from beneath the floor slab. In order to maintain the structural integrity of the residence, a professional engineer specializing in structural support and foundation stabilization prepared a site specific Structural Excavation Plan, which included the use of structural timber and resistance piers. Through our successful remediation, a significant mass of contaminated soil was removed, to a maximum depth of 13 feet below the basement floor, or 19 feet below exterior grade. Additional contaminated soil remained at depth and could not be excavated due to safety concerns.

Post-excavation soil gas data indicated that air-phase petroleum hydrocarbons was present at elevated levels. As a result, Omni Environmental Group designed, installed, and operated a soil vapor extraction (SVE) system to reduce petroleum concentrations. The SVE system operation, associated rebound studies, and soil gas sampling activities resulted in the reduction of petroleum in soil gas to levels below recommended MassDEP sub-slab residential concentrations.

The subsequent risk characterization concluded that a condition of No Significant Risk existed and supported the submission of a Permanent Solution Statement with No Conditions which closed the environmental case.