General Mills/Henkel Corp.: Five-year review of TCE soil vapor

The MPCA has prepared the sixth five-year review report (dated June 2021) for the General Mills/Henkel Corp. Site. The purpose of the report is to assess the site cleanup activities and ensure that human health and the environment remain protected.

Site background

From 1947 through 1977 General Mills, Inc. (GMI) conducted chemical research at the site. Workers dumped waste volatile organic compound (VOC) solvents containing trichloroethylene (known as TCE), in a soil absorption pit from 1947 until 1962. GMI investigated the absorption pit in 1981, and reported to the MPCA that there was contamination of soil and groundwater in the absorption pit area.

An October 23, 1984, Response Order by Consent between the MPCA and General Mills provides the basis for remedial activities at the Site. The groundwater cleanup remedy consisted of a groundwater pump-out system to control the groundwater contaminant plume as well as remediate contaminated groundwater. Extraction and treatment of impacted groundwater to stabilize the plume of VOC contamination began in 1985 and ran until 2010.

In October 2013 the MPCA received soil gas data indicating potential soil gas vapor intrusion into buildings in the vicinity of the site. The potential for vapor intrusion was not addressed in the 1984 Response Order by Consent and is not part of this Five-Year Review.

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