State officials are asking residents of the Como neighborhood in southeast Minneapolis for permission to test their homes for the presence of a potentially harmful vapor.
The soil vapor is called trichloroethylene, or TCE. The industrial solvent was used at a General Mills research facility at a nearby site between the 1940s and 1960s, according to state officials. Residents were notified about the potential for contamination in a letter sent out this week.
Officials don't expect that levels of TCE would be high enough to cause immediate health problems, said Jim Kelly, manager of the Environmental Surveillance and Assessment Section at the Minnesota Department of Health. They're more concerned about the long-term health effects.
"The concern with exposure to TCE is it can potentially lead to an increased risk of cancer over long periods of exposure," Kelly said. "Exposure to TCE is also associated with an increased risk of birth defects or effects in the immune system of particularly susceptible individuals."
State officials want to test about 200 homes in the area to see if TCE could be getting inside, Kelly said.
In order to do the test, in which a contractor drills a hole in a basement and collects a vapor sample, the agencies need the homeowners' approval.
If there is contamination, General Mills has agreed to install vapor ventilation systems, which are similar to radon mitigation systems and typically cost between $1,000 and $1,500 each, Kelly said. There will be no cost to the homeowner.
Minnesota Pollution Control Agency Superfund Program supervisor Hans Neve said General Mills followed common disposal techniques used up until the 1960s.
"This was the state of understanding at that time that waste solvents, if you put them in a hole, they would go away," Neve said. "But we learned several decades later that there is no place called 'away' and exposure to chemicals like this is going to certainly cause groundwater contamination."
Neve said contaminants were found in water on the site in 1981. A water treatment system was active between 1985 and 2010. He said recent scientific developments have shown that water contamination can lead to a vapor being released, leading the agencies to more closely monitor the site.
Officials are holding two community meetings next Tuesday at Van Cleve Recreation Center.
The full news release is here