MINNEAPOLIS (WCCO) — The Minnesota Department of Health has launched a new tool to help people see radon levels in their counties.

Radon — an odorless, colorless gas that occurs naturally in Minnesota soils — is the leading cause of lung cancer among non-smokers.

Radon can enter a house through the cracks or openings in walls or foundations.

MDH created a new interactive county-by-county map which uses data from the last five years.

Health officials say about two in five Minnesota homes have dangerous levels of radon gas.