Chloroform causes kidney and liver tumors in animals, and the EPA lists the chemical as a probable human carcinogen. However, before you give up showering for the rest of your life, consider this. Chloroform is not a typical carcinogen, in which exposure to even a single molecule can set cancer in motion. Instead, evidence indicates that chloroform must reach a certain threshold concentration before it initiates the cancer-causing process, says Buckley. Those who want to be on the safe side can reduce exposure to chloroform by improving ventilation in the bathroom and drinking bottled water.
Exposure can be deadly.
Being married to a smoker raises lung cancer risk 25 percent, according to data pooled from several studies. Children of smokers have a greater risk of respiratory infections and slower lung growth. And environmental tobacco smoke is also responsible for an estimated 35,000 to 40,000 cardiovascular disease deaths per year, according to the American Heart Association. ETS may contribute to other cancers too, as well as premature menopause, sudden infant death syndrome, and lower birth weight. The best way to reduce risk is to avoid smoking.