The Minnesota Pollution Control Agency has completed the excavation and removal of petroleum contaminated soil from the site of a former Texaco gas station in New York Mills.
According to MPCA Project Leader Arlene Furuseth, more than 3,000 yards of earth were removed and applied at an approved land disposal site where the action of sunlight and air will eventually breakdown the petroleum products contained in the soil. The project involved drawing down several feet of groundwater at the site to facilitate the dig. Collected water was treated onsite with a portable wastewater treatment system to remove all petroleum products before being discharged to a nearby ditch.
Furuseth said during the excavation process, petroleum fumes could be detected throughout the neighborhood but these fumes should only be temporary and will be gone from the area soon if they aren't already. Construction workers monitored the air throughout the project and were authorized to suspend work if vapor levels became extreme.
Petroleum contamination was discovered at the site several years ago when a nearby resident reported a strong oil smell in the basement following a heavy rain. An investigation revealed water entering the basement contained petroleum products that likely migrated to the home in groundwater from a source below the nearby closed gas station.
The owner of the home decided to fill in the basement with sand and install a vapor barrier/collection system on top of the sand that would capture and disperse any vapors to a vent on the roof.
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Furuseth said the MPCA did follow-up testing that showed the system was working and vapors have not been detected since the system was installed. She said air samples will be taken at the home to ensure the vapor collection system is still working effectively. The family living in the home will be provided with hotel lodging during the sampling process. Air samples will be collected over a 24-hour period from four locations: one just outside the home, one inside the home, one just above the vapor barrier located beneath the home and one at the vapor collection system vent outlet. Furuseth said results of the testing will be available in a few weeks.
