New research suggests it's not just second-hand smoke you should watch out for.
Lingering tobacco smoke, also known as third-hand smoke, is doing more than making the room hazy: it can also leave cancer-causing toxins behind.
Researchers from Lawrence Berkeley National Laboratory tested a 45-year-old pickup truck driven by a heavy smoker and found that cancer-causing agents were left behind on many surfaces years after lighting up.
According to the research children and infants are the most likely to pickup the deadly toxins.
"That young child who is hugging their grandpa and ingesting (the toxins) into their lungs that are developing could cause an asthma attack. There is led in third-hand smoke, and so those young children are ingesting it into their young brains and lungs are at risk for learning disabilities, you know, it's a Russian roulette. Are you really willing to play that game?" said Judi Zabel with the La Crosse Co. Health Department.
Health experts say a good cleanup could help remove some the potentially harmful chemicals.