It’s difficult to pay attention to a threat that can’t be seen, one that creeps up silently from the ground into buildings.

But radon demands being taken seriously.

January is National Radon Action Month, to raise awareness about this colorless, odorless gas that according to the U.S. Environmental Protection Agency is the nation’s second-leading cause of lung cancer deaths in the United States — costing about 20,000 people their lives each year — and the leading cause among non-smokers.

Radon is produced from the decomposition of uranium and shares its dangerous trait of being radioactive. It can percolate up through soil and rock, accumulating in homes, public buildings and workplaces without giving any sign of its presence.

Elevated radon levels — above 4 picocuries per liter, according to the EPA — can be found in every Michigan county, with testing in some counties revealing more than 50 percent of homes had radon levels above the recommended limit, according to Gov. Rick Snyder’s official proclamation of January as Radon Action Month in Michigan.

Which is why radon testing is crucial, according to the Michigan Department of Environmental Quality.

In observance of Radon Action Month, the Dickinson-Iron District Health Department in January has cut the cost for the short-term radon test to $5. For more information on the DIDHD’s radon program, call 906-779-7239.

In Wisconsin, Florence County offers test kits for only $10, or they can be obtained from most hardware stores “at a modest price,” the Florence County Health Department advised. These tests are easy to use, with a simple package to mail in for results, according to the department.

The health department is on the first floor of the courthouse and is open 8:30 a.m. to 4 p.m. Monday through Friday, except from noon to 12:30 p.m. for lunch.

For more information about radon, call the Florence County Health Department at 715-528-4837 or go to the Wisconsin state website at www.lowradon.org. or the EPA site at www.epa.gov/radon/pubs/citguide.html. The toll-free statewide phone number is 1-888-LOW RADON.

The Michigan DEQ, with aid from the EPA, also offers a toll-free radon hotline at 800-RADON GAS/800-723-6642 that offers information on the health risk, how to test, how to interpret results, how to reduce elevated radon levels and more. The literature is free and program staff can help locate do-it-yourself test kits, professional testers and radon reduction contractors, according to the DEQ.

Place the calls or go online. Learn whether radon has infiltrated and take the steps needed to drive it out.