CHAPEL HILL, N.C. (WNCN) – Children touch everything and that makes them especially vulnerable to third-hand smoke, which is the chemical residue from tobacco left in dust and on surfaces.

“Third-hand smoke is really concerning in large part because people aren’t as much aware of it,” said Dr. Adam Goldstein, professor of family medicine at UNC-Chapel Hill.

A new study from San Diego State University and the University of Cincinnati finds almost all children have tobacco on their hands.

Researchers swabbed the hands of about 500 children ages 11 and younger and found more than 97 percent of the swabs contained some level of nicotine.

The study also finds 95 percent of the kids who come from non-smoking households still had nicotine detected on their hands.

“It’s alarming because virtually all of the kids, particularly those that were unexposed by their parents, they don’t smoke, there’s nothing in the environment that they would know of, virtually all of them did have some exposure to nicotine,” said Goldstein. “It’s concerning because there really is no safe threshold of third-hand smoke exposure.”

Goldstein said third-hand smoke can be active on surfaces for months – even years.

“People can touch it, people can breathe in, and that exposure is very cancer-causing,” he said.

As for what parents can do, Goldstein said take a good look at the environments where kids live, work, and play.

“We need to be working on tobacco-free parks, beaches, indoor areas, all the places where the kids also go and are exposed,” Goldstein said. “Again, most of these kids were five years of age in this study. It wasn’t like they had control over their environments. It’s where we as parents often times allow them to be.”