A habit meant to keep you from getting gum disease could be making you sick in other ways.

A new study says a popular brand of dental floss has toxic chemicals in it. Researchers found women who used the Oral-B Glide floss ended up with high levels of per- and polyfluoroalkyl (PFAs).

PFAs are used in non-stick pans, carpet and firefighting foam. They are linked to cancer, thyroid problems, liver damage and immune system problems.

USA Today reports Oral-B says it did not find any of the substances in the study in its floss , and the floss always undergoes safety testing.

Other things that contain high PFAs, according to the study, are stain-resistant household goods such as carpet and furniture. And if a city's water is contaminated, PFAs are usually in it.

The Centers for Disease Control and Prevention lists some hygiene products and microwave bags also potentially containing PFAs.

Oral-B released a statement in response to the study.

"We have confirmed none of the substances in the report are used in our dental floss," Oral-B said in a statement. "The safety of the people who use our products is our top priority. Our dental floss undergoes thorough safety testing and we stand behind the safety of all our products."