As many of you have heard, many Como neighbors between 17th and 23th Ave SE were alerted that their basement air may contain Trichloroethylene (TCE) vapor. TCE is an industrial solvent and degreaser. Recent studies confirm TCE is a carcinogen, a neurotoxin and increases the risk of some heart related birth defects.
The contamination comes from the General Mills/Henkel Corp. Superfund Site at 2010 E. Hennepin. From 1947-1962, General Mills dumped of thousands of gallons of industrial waste (predominantly TCE) into an absorption pit on the property. In 1981, General Mills (GMI) investigated and reported that the pit had caused soil and groundwater contamination. In 1985, under MPCA supervision, GMI began to pump and treat the groundwater, removed the pit and left the contaminated soil. In 2010, the MPCA allowed GMI to stop pumping.
New understanding about TCE pollution triggered well-vapor samples in 2011 and this April. Soil samples taken in October, 8 feet down in City right-of-ways across Como confirmed the presence of TCE vapor. While there is no risk of exposure in open air, vapor intrusion in basements allows the vapor to collect and is a risk.
Barr engineering was contracted by GMI to test about 200 homes between 17th and 23rd Ave SE. Homes in the testing zone received a letter and were invited to public meetings on November 12. More homes may require testing, depending on the results. To test, the homeowner/landlord must sign an access agreement. Engineering then come in and drill a small hole in the basement slab and sample the air directly below.
If TCE Vapor is found above 20 micrograms/cubic meter, Barr will install a vapor mitigation system. These systems are identical to those used for radon mitigation. For homes in the current or future testing zones, the test and possible mitigation system are free. SECIA is keeping in touch with MPCA, Barr, GMI, MDH, local politicians, the city and others. We are extending invitations to upcoming meetings as well as bringing on a environmental consultant to assist in document review.
Additional information about this project is found at www.pca.state.mn.us/. For more information, questions or comments, you can contact these representatives:
Minnesota Pollution Control Agency (for project or testing questions)
To schedule sampling, call: Sara Gaffin, Barr Engineering, (952) 832-2935
To contact General Mills, call: (763) 293-1165