Pinnacle Engineering was hired to perform a Phase I Environmental Site Assessment for a former automobile dealership in preparation for redevelopment of the site as a commercial/retail development. The Phase I identified several environmental concerns, including the presence of underground storage tanks, hydraulic hoists, and a floor drain-sump system. During their removal, both petroleum and non-petroleum contaminants were identified in soil under the tanks and hoists, as well as in residue in the sump.

To get liability assurance for a redevelopment loan, the site was enrolled in the Minnesota Pollution Control Agency (MPCA) Voluntary Investigation and Cleanup (VIC) program and Petroleum Remediation Program (PRP).  The client subsequently retained Pinnacle to complete a Limited Site Investigation (LSI) to define the extent of petroleum contamination. Pinnacle also prepared a Response Action Plan (RAP) for the remediation of contaminated soil that would be disturbed in redevelopment of the site, and oversaw implementation of the approved RAP. All work was done in accordance with MPCA PRP and VIC requirements.

As a result of the investigation and remediation, the MPCA closed the petroleum portion of the release. However, significant non-petroleum impacts were found in groundwater and soil vapor. Pinnacle conducted additional investigation, both on- and off-site, to delineate the magnitude and extent of the impacts and to determine whether environmental risks existed to adjacent residential properties or future occupants of the redeveloped site buildings. This additional assessment included installing soil vapor monitoring ports in the floor of the site building, obtaining permits from the City for installation of permanent soil vapor monitoring ports in an alley, and advancing soil borings on City sidewalks to collect groundwater and soil vapor samples. The assessment revealed a minimal risk to the residential properties. A limited risk was found to the site structure, but soil vapor levels diminished in subsequent sampling, likely due to the removal of contaminated soil in the RAP implementation. Data also indicated that at least a portion of the non-petroleum impacts may have originated from an off-site source.  Pinnacle reviewed file information at the MPCA regarding a long-closed release from a drycleaner approximately 500 feet from the site. This information indicated that the previously resolved release, which had been closed before current soil vapor guidelines were established, may be contributing to the site impacts.

Based on assessment work conducted by Pinnacle, the owner and lenders obtained liability assurances required to finalize the redevelopment project.