Carlson McCain (CMC) was hired as an environmental consultant to assist in the excavation of multiple abandoned underground storage tanks (USTs) at a site in St. Cloud, Minnesota. The site is an asphalt parking lot for a recently demolished Perkin’s restaurant. Historically, the site operated as a gas station prior to 1970.

August 2021

A Phase II Environmental Site Assessment (ESA) was conducted by another consultant at the former Perkins (Site). The Phase II ESA Report identified petroleum-impacted soil and groundwater at areas of suspected abandoned underground storage tank’s locations. The MPCA subsequently assigned it a Leak-site.

October 2021

CMC employees went on-site to confirm the presence of USTs at the Site. A total of three steel “orphan” USTs were confirmed and measured. The information gathered about the USTs assisted the property owner in entering the Minnesota Department of Commerce (MDC) – Petrofund Abandoned Petroleum Storage Tank Removal Program.

November 2021

Carlson McCain and Service West Contracting, Inc. (SWC) personnel were on-Site for the removal of one 4,000-gallon and two 3,000-gallon petroleum USTs. The steel USTs were removed as part of the MDC – Petrofund Abandoned Petroleum Storage Tank Removal Program. Carlson McCain personnel collected a total of seven soil samples for field screening purposes during tank removal. Zahl Petroleum & Equipment (Zahl) was also onsite to pump 775 gallons of liquid and 60 gallons of sludge from the USTs.

The removed USTs appeared in poor condition, consisting of heavy rusting and pitting throughout the tank surfaces. Cracks or holes were not observed throughout each UST surface. Field screening activities, including visual and olfactory observations, did not identify petroleum-impacted soil (sand) below and around the removed USTs. Laboratory analysis of soil samples identified relatively low magnitude DRO concentrations. No other compounds were present at concentrations above laboratory detection limits.

Conclusions

Based on the groundwater impacts identified during the previous Phase II ESA, Carlson McCain recommended a standard scope of work Limited Site Investigation (LSI). The LSI was completed by CMC employees in early 2022.

Location: St. Cloud, Minnesota

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