The hazards of tobacco use are making headlines once again. Researchers at the prestigious Berkeley Lab presented a new global warning on the risks of third-hand smoke. The study published in the journal Mutagenesis confirms cancer-causing toxic tobacco residues can cause significant genetic damage in human cells. The results of the study also confirm a harmful cumulative effect of the hazardous residues over time. Researchers found long-term exposure to third hand smoke resulted in more DNA damage than short-term. "Studies show that third hand smoke clings to hair, skin, clothes, furniture, drapes, walls, bedding, carpets, dust, vehicles and other surfaces, even long after smoking has stopped,” says Lowell Dale, M.D.Third-hand smoke is a relatively new concept and is characterised by the invisible residues left behind once second-hand smoke has disappeared. Third-hand smoke is thought to be particularly dangerous to infants and young children because they are more likely to inhale, ingest and touch surfaces containing the toxic residue. "This is the very first study to find that third-hand smoke is mutagenic,” said Lara Gundel, co-author of the study. "Tobacco-specific nitrosamines, some of the chemical compounds in third-hand smoke, are among the most potent carcinogens there are. They stay on surfaces, and when those surfaces are clothing or carpets, the danger to children is especially serious.”To complicate the seriousness of the problem, the residue can react with other common indoor air pollutants such as ozone and nitrous acid. These new ultrafine particles have been found to pass directly into human tissues through inhalation, ingestion and skin contact."Until this study, the toxicity of third-hand smoke has not been well understood,” says Bo Hang, lead researcher and biochemist in the Life Sciences Division of Berkeley Lab. "Third-hand smoke has a smaller quantity of chemicals than second-hand smoke, so it’s good to have experimental evidence to confirm its genotoxicity.”Even more alarming, third-hand smoke residue builds up on surfaces over time and it becomes virtually impossible to remove the noxious residue. Common cleaning methods such as sweeping, vacuuming and wiping have not proven effective in eradicating the cancer-causing residue. Studies have confirmed that the residue can still be detected in dust and surfaces for more than two months after smokers have left. "You can do some things to reduce the odour’s, but it’s very difficult to really clean it completely,” says Hugo Destaillats, co-author of the study. "The best solution is to substitute materials, such as change the carpet, repaint.”The researchers conclude in their paper: "Ultimately, knowledge of the mechanisms by which third-hand smoke exposure increases the chance of disease development in exposed individuals should lead to new strategies for prevention.”Second-hand smoke is the smoke that comes from being in close proximity to burning tobacco products. This type of hazard is removed when smoking has ceased. In third-hand smoke, airing out rooms, opening windows and/or using fans can’t eliminate the toxic residue. The only way to protect oneself from third-hand smoke is to create a smoke-free environment. Strive to make your home and vehicle safe for you and your children. Reduce your risk by avoiding restaurants, bars and public places that are exposed to first, second and third-hand smoke. Dr Cory Couillard is an international healthcare speaker and works in collaboration with the World Health Organization.Facebook: Dr Cory CouillardTwitter: DrCoryCouillard