The deadly health impacts of smoking and inhaling secondhand smoke are widely known, but a third type of danger remains long after the smoke clears.
It is known as thirdhand smoke, the residual contamination from tobacco smoke.
"Carcinogens hang around," said Indiana State Health Commissioner Dr. William VanNess.
Pediatricians were among the first to notice the effects of thirdhand smoke, said Miranda Spitznagle, director of the Tobacco Prevention and Cessation Commission of the Indiana State Department of Health.
"People kind of perk up and say, 'What's that?'" she said.
Smoking releases toxins.
"That smoke and its constituents land somewhere – furniture, carpets, drapes, the walls," Spitznagle said. "The chemicals and toxins are still there. They're still on something."
An infant crawling on a carpet is exposed to the smoking remnants embedded in carpet fibers or settled on the surface, she said.
"I think anybody who is in a room or is close to a piece of clothing where there has been active smoking, you can still smell it," she said.
Smokers who are trying to quit or try to limit exposure to others by smoking outside are still guilty of carrying the smoking remnants on their clothes.
"And then they pick up their child and that child is going to breathe in whatever they have on their clothing," Spitznagle said. "We want to eliminate any exposure."
On its website, Americans for Nonsmokers' Rights cites a 2010 study published in the Proceedings of the National Academy of Sciences of the United States of America that shows how thirdhand smoke causes the formation of carcinogens.
"The nicotine in tobacco smoke reacts with nitrous acid – a common component of indoor air – to form the hazardous carcinogens," the website states. "Nicotine remains on surfaces for days and weeks, so the carcinogens continue to be created over time, which are then inhaled, absorbed or ingested."
Indiana has made great progress over the last 10 to 12 years in terms of having smoke-free homes. The more research that is shared, the more people understand the dangers of smoking, Spitznagle said.
"We're continuing to learn that tobacco smoke is much more deadly," Spitznagle said.
The effects of secondhand smoke are becoming clearer.
"If you work in a smoke-filled room eight hours a day, it's the equivalent of smoking a pack a day yourself," VanNess said.
It also translates into added health costs.
"For every pack of cigarettes somebody smokes, it costs us $7.56 in health care costs, and it costs us over $15 in lost productivity," VanNess said. "Smokers are sick more, are off more."
Spitznagle said there are free resources to help smokers who are ready to quit, available by calling (800)-784-8669.