The EPA and National Center for Disease Control list radon as the second leading cause of lung cancer, next to smoking, and estimate up to 20,000 lung cancer deaths a year in the U.S. are connected to the gas. Most houses in the country are radon-free, but scientists say radon gas is present in some 8 million homes in 30 states. The only way to be sure is to have the indoor area tested for radon. Secondhand or environmental tobacco smoke is the smoke exhaled by smokers as well as the smoke from a burning cigarette. It contains hundreds of toxic chemicals, including the carbon monoxide, nitrogen dioxide and formaldehyde listed above.
Some experts call smoking the single most deadly exposure of all indoor air pollutants.
Sue waited a long time for her new carpet, and smiled in satisfaction as she watched her energetic infant crawl across the plush shag. Sue was lucky. Her pediatrician recognized the baby's symp toms as formaldehyde poisoning and they were able to pinpoint the carpet as the culprit. Once it dissipates, the products are harmless. It has also been linked to cancer and Sudden Infant Death Syndrome.