7 Cancer-Causing Items in Your House These 7 common household items may be raising your risk of cancer. 1. Tap water polluted with nitrates may be the cause of 12,594 cases of cancer, according to the non-profit Environmental Working Group. 2. Carpet made of synthetic fibers may "off-gas" chemicals that raise risk of cancer, hormone disruption and respiratory disorder. 3. Mattresses coated with flame-retardant chemicals may be linked to increased cancer risk, according to the Consumer Product Safety Commission. 4. Cotton pillowcases and sheets are often doused with harmful pesticides. 5. Air fresheners may contain harmful chemicals under the vague name "fragrance," according to the Journal of Building and Environment. 6. Dry-cleaned clothes are often treated with perchloroethylene, a known neurotoxin, according to the Environmental Protection Agency. 7. Granite countertops may give off harmful levels of radon gas, according to a study by the Journal of Radioanalytical and Nuclear Chemistry.