Mike Sommer, a radon mitigation installer for Advanced Radon Services LLC, installs a radon suction fan above a garage during radon mitigation of a home in Stillwater that was recently sold.

David Joles, Star Tribune

Radon a risk in Minnesota homes

  • Article by: William J. Angell
  • July 24, 2013 - 7:53 PM


In a July 19 counterpoint (“Despite a Star Tribune story, radon is a diminishing risk”), Chad Kompelien, president of the Builders Association of Minnesota, claims that since 2009, some buyers of new Minnesota homes have had to pay for a passive radon control system they’ve never needed. There are serious shortcomings in this claim.

First, there are more U.S. homes with elevated indoor radon than any time in our history, because many new homes are sold each year with high radon concentrations. Unless builders install effective radon-control systems, they will continue to create a greater risk of radon-induced lung cancer for their customers.

Second, Kompelien appears to assume that buyers receive no benefit from a radon-control system if their new homes have indoor radon concentrations below the U.S. Environmental Protection Agency’s action level of 4 picocuries per liter. But that does not mark a safe level of radon exposure. Any exposure carries a risk of lung cancer.

Exposure in the home to 4 pCi/L carries a risk of lung cancer death of one in 50. This risk exceeds the risk of death due to car accidents, residential fires and accidental carbon monoxide exposure in the home. At lower radon concentrations, the risk reduction is relatively linear, but the risk is never zero. If your new home’s radon-control system reduces your family’s exposure from 3.8 to 1.9 pCi/L, you receive the benefit of about a 50 percent reduction in exposure.

Third, Kompelien fails to quantify the modest cost of a passive radon-control system in homes. According to the 2009 National Association of Home Builders survey of members, the average cost of passive radon control in new houses was $300, and the cost for a fan driven system, which gives greater radon reduction, was $600. Compared with the cost of a new home, radon-control systems are a bargain.

While Minnesota’s Building Code radon requirements have produced reasons to celebrate, too many builder-installed radon systems remain insufficient for risk reduction. All homes, including new homes with radon systems, should be tested; that is the only way to know the indoor radon concentrations.

I would welcome the Builders Association’s support for more effective radon risk reduction in new homes. Minnesota’s Building Code is only one step in the right direction.


William J. Angell is a professor at the University of Minnesota and member of the World Health Organization’s International Radon Project.

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