UNDATED -- As winter sets in, state health officials want you to be aware of some indoor air issues.

First, try to keep mold from forming in your window sills and other areas of your house where the humidity can be high.

Invest in a radon test kit to make sure your home is free from the radioactive gas. Radon is a naturally occurring radioactive gas that comes from the soil.

Josh Kerber is an Environmental Research Scientist with the Minnesota Department of Health. He says one in three Minnesota homes has radon levels above the acceptable limit and the health department recommends every home in the state be tested.

Kerber says 21,000 people in America die every year from lung cancer brought on by radon gas.

And finally, have a working carbon monoxide detector in each room of your house. Kerber says if you are using a propane or kerosene heater in a garage or fish house, make sure you have proper ventilation.

In fact, just last week a Becker man had to be hospitalized because of carbon monoxide poisoning after a propane heater wasn't properly vented in a detached garage he was working in.