GRAND RAPIDS, Mich. (WOOD) — January is National Radon Action Month and health departments in several West Michigan counties are encouraging residents to check their homes for the health hazard.

Radon is a radioactive gas that is found in about 17% of the homes tested in Kent County, the health department says. Although you can’t see, smell or taste the gas, radon can kill. It is the second-leading cause of lung cancer in the U.S., according to the surgeon general.

The Kent County Health Department and Barry-Eaton District Health Departments both recommend you test your home every few years. Even if you’ve tested before, widening cracks in your home’s foundation or the house settling can open new pathways for radon to enter your home, KCHD said.

“Testing is the only way people can know if radon is reaching into their house,” said Rusty Flewelling, supervising sanitarian with KCHD.

To get a free radon kit in Kent County, go to the health department’s main clinic at 700 Fuller Ave. NE in Grand Rapids Monday through Friday from 8 a.m. to 5 p.m while supplies last.

In Barry and Eaton Counties, there are several pickup locations:

In Berrien County, you can pick up free testing kits through February at the county health department offices at 2149 E. Napier Ave. in Benton Harbor and at 1205 N. Front Street in Niles.

To use the kit, you hang a filter inside your house for a few days and then send it in a self-addressed, pre-stamped envelope for testing. Your results will be sent back to you.

For more information about radon in Michigan homes, you can listen to a podcast by KCHD or visit the Barry-Eaton District Health Department website.