UNITED NEWS INTERNATIONAL (UNI) — Teens who smoke e-cigarettes may be inhaling chemicals that increase their risk of cancer.

New research published March 5 in the journal Pediatrics suggests teenaged e-cig users are poisoning themselves with some of the same dangerous chemicals in tobacco-based cigarettes.

Vaping uses a device that heats vapor, which the user then inhales. The vapor may contain nicotine and fruity flavoring.

Study members analyzed urine samples from over 100 teens around the age of 16.

Researchers found those who used e-cigs has up to three times higher levels of toxic chemicals in their systems than those who didn’t vape.

Those chemicals were even present in those who used e-cigs that didn’t include nicotine.

Lead study author Mark Rubinstein said, “Teenagers need to be warned that the vapor produced by e-cigarettes is not harmless water vapor.”

The Tobacco Vapor Electronic Cigarette Association says there’s no evidence linking e-cig use to cancer.