“Test for radon. Save a life.” That’s the motto of Radon Awareness Week, which starts today. Sponsored by nine federal agencies, the week is intended to focus on radon risks and the fact that radon causes 22,000 lung cancer deaths a year, second only to smoking.

According to the group’s website, radonweek.org, “Radon is naturally occurring, odorless and colorless gas produced by the breakdown of uranium in soil, rock and water. Because radon is a gas, it can enter buildings through openings or cracks in the foundation. The radon gas itself decays into radioactive solids, called radon daughters. The radon daughters attach to dust particles in the air, and can be inhaled. The inhalation of radon daughters has been linked to lung cancer.”

In June, the federal agencies teamed up to form the Federal Radon Action Plan, which aims to not only raise awareness but develop expertise and jobs in radon testing and mitigation. The plan’s goals include making testing for radon gas a requirement during real estate transactions and routinely testing schools, workplaces and daycare facilities.

Homes with elevated radon levels have been found in practically every county in the nation. Because of that, the working group recommends that every home be tested for radon regardless of where it’s located, how old it is, the type of foundation or whether or not the home is in an area where homes are “prone to having radon problems.”

In Consumer Reports' tests of short-term radon kits, we found only one—the RTCA 4 Pass Charcoal Canister—accurate enough to recommend. But you should still confirm its results with a long-term test. Radon levels can vary significantly from day to day so sampling the level for 90 days or more gives you a more accurate idea of the average radon level in your home. For more information, read A Citizen's Guide to Radon from the Environmental Protection Agency.