FS Engineers, Inc. (FSE) prepared a Phase I Site Investigation and Tier Classification along with an Immediate Response Action (IRA) Plan for a Massachusetts residential property with an abandoned underground storage tank (UST).

The 275-gallon fuel oil UST was located in the front yard of the property and had been abandoned for over 15 years. Evidence of contamination of the surrounding soil had been observed during the removal of the UST. The residence was located in a high yield aquifer area within an Interim Wellhead Protection Area, and was therefore subject to the most stringent groundwater cleanup standards under Massachusetts Contingency Plan (MCP) regulations.

FSE prepared an IRA Plan in which excavation and In-Situ Chemical Oxidation (ISCO) were the methods chosen to remediate the contaminated area. Following the approval of the IRA Plan by the Massachusetts Department of Environmental Protection (MassDEP), FSE oversaw the remedial action program at the property. FSE managed the off-site transport and disposal of soils generated from remediation activities, according to MCP guidelines. Soil borings were subsequently advanced at the property and completed as groundwater monitoring wells. Soil and groundwater samples were collected for laboratory analysis to characterize the site conditions. Following analysis of the subsurface conditions, the ISCO method chosen at the site was the application of 100 pounds of Oxygen BioChem (OBC)™ in selected injection points at the property.

At the completion of response actions, the site was returned to the pre-existing background conditions. An IRA Completion Statement and Class A-1 Response Action Outcome (RAO) Statement were submitted to the MassDEP.