…And now researchers have found that there is a new worry for non-smokers out there: “Third-hand smoke.”

According to an article in the New York Times, scientists have discovered a toxic yet invisible residue left behind after someone smokes. Unlike the second-hand smoke that someone can blow out a window or fan out of a room, these dangerous particles get stuck to surfaces like rugs, clothing and the fabric on a couch.

Also unlike second-hand smoke, which people can obviously see, people do not realize that these particles exist, which makes them even more dangerous. The article explains that the smell on someone’s clothes or in a room after someone smokes is a sign that the toxic chemicals are still present. So, just because the smoke has cleared from a room or car doesn’t mean that the air is clean and safe.

“There are carcinogens in this third-hand smoke, and they are a cancer risk for anybody of any age who comes into contact with them.”

This is something to think about if you are a smoker or know someone who is. This may also be a sign that banning smoking in restaurants and bars isn’t enough; soon they may make you change your clothes when you get back from having that much needed cigarette.