MINNEAPOLIS (WCCO) – The city of Minneapolis announced on Thursday that it’s giving away 200 radon test kits, for homeowners to use to check if their homes contain dangerous levels of the cancer-causing gas.

Residents can pick up free kits at the City of Minneapolis Development Review, located at 250 S. Fourth St., Room 300, from 8 a.m. to 4 p.m.

After the supplies run out, homeowners can still purchase a kit for $9.

Radon is the leading environmental cause of cancer deaths in the United States, and the leading cause of lung cancer among nonsmokers, according to a release. It’s an odorless, colorless and tasteless gas that occurs naturally in Minnesota soil. It can enter homes through cracks and openings in their foundations or walls.

The Minnesota Department of Health estimates that two out of every five homes in Minnesota have dangerous levels of the gas.