Radon Not the Only Soil Gas to Poison Minnesota Homes

The Minnesota Pollution Control Agency is finding that soil vapors are bringing long-ago buried pollution into basements and houses.

A Minnesota state agency is currently reviewing 293 sites where it thinks vapor intrusion from soil might be putting people at risk—but its not radon they’re concerned about; it is industrial solvents dumped decades ago.

The Minnesota Pollution Control agency decided in 2008 to revisit cleanup sites that had been closed years ago after it discovered that chemicals that may have been dumped there—and considered safely buried—could vaporize and rise through the soil into the basements of homes and businesses (see “Radon and Other Soil Gases: Dealing with Hazards from Below”). Among 53 known problem sites, eight had been dry cleaning businesses, and another was an old General Mills research plant where the chemical trichloroethylene (TCE) was commonly dumped outdoors from 1949 to 1962. TCE has since been linked to higher risk of cancer, birth defects, and mood disorders.

Mitigation systems have now been installed in eleven homes, reports the StarTribune; mitigation efforts consist of negative-air-pressure systems that draw vapors out of the soil, and General Mills has agreed to pay for more than 100 more. However, Minnesota is just a start; other states have not even begun to review polluted sites for vapor risks.