Third-hand smoke clinging to indoor surfaces may pose risk

Cigarette smoke that clings to walls, furniture and fabrics is a smelly nuisance, but U.S. researchers suggest it may damage DNA increasing cancer risk. Bo Hang, a staff scientist at the Lawrence Berkeley National Laboratory, said third-hand smoke could pose a serious threat, especially to young children who put toys and other smoke-affected items into their mouths. Hang's research showed NNA, a tobacco-specific nitrosamine, locked onto DNA to form a bulky adduct -- a piece of DNA bound to a cancer-causing chemical -- as well as other adducts, in lab test tubes. Other large compounds that attach to DNA tend to cause genetic mutations. NNA also breaks the DNA about as often as a related compound called NNK, which is a well-studied by-product of nicotine and a known potent carcinogen. This kind of DNA damage can lead to uncontrolled cell growth and the formation of cancerous tumors, Hang said. Although many public places ban smoking, Hang said 44 million U.S. adults reported smoking cigarettes in homes and 4 million reported smoking every day. The best way to get rid of third-hand smoke is by removing affected items, such as sofas and carpeting, as well as sealing and repainting walls, Hang said. Sometimes even replacing contaminated wallboard was necessary, he added. Replacing furniture can be pricey, but Hang said vacuuming and washing clothes, curtains and bedding could help. The findings were reported at the 247th National Meeting & Exposition of the American Chemical Society in Dallas.