A health watchdog group took legal action against some of the country’s largest e-cigarette manufacturers for failing to properly warn consumers about the risk of such products after tests show that most produce high levels of toxic chemicals.

The Center for Environmental Health conducted tests of 97 e-cigarettes and other “vaping” products from two dozen makers including Imperial Tobacco’s Vuse brand, NJoy, and RJ Reynolds’ blu brand for the report [PDF] titled “A Smoking Gun: Cancer Causing Chemicals in E-cigarettes.”

The report – which the group claims is the first-ever large sampling of actual e-cigarettes and vaping products tested simulating real-world use – found that 50 out of the 97 e-cigarettes tested pose a serious cancer risk.

The products used in the tests were purchased at easily accessible businesses such as 7-Eleven, Rite Aid, online retailers, and vape stores in the Bay Area.

According to the report, 90% of the companies had at least one product that produced high levels of formaldehyde or acetaldehydeone or both, representing a violation of California safety standards.

The two chemicals have been found to cause cancer and are also linked to genetic damage, birth defects and reduced fertility.

“The testing showed that 21 products produced a level of one of the chemicals at more than ten times the state safety standard, and seven products produced one of the chemicals at more than 100 times the safety level,” said CEH in a press release on Wednesday.

While some consumers believe that nicotine-free e-cigarettes are safe, the CEH testing found high levels of the chemicals even in several of these varieties.

For example, the report found one nicotine-free product produced acetaldehyde at more than 13 times the state legal safety threshold and formaldehyde at more than 74 times the threshold.

“Anyone who thinks that vaping is harmless needs to know that our testing unequivocally shows that it’s not safe to vape,” said Michael Green, Executive Director of CEH. “This is especially troubling given the reckless marketing practices of the e-cigarette industry, which targets teens and young people, and deceives the public with unfounded health and safety claims.”

In its legal claims [PDF], the group alleges that e-cigarette manufacturers are breaking California’s consumer protection laws.

“Our legal action aims to force the industry to comply with the law and create pressure to end their most abusive practices,” Green says.

According to the legal actions, the companies can resolve the issues if they agree to a binding agreement that recall products already sold, provide clear and reasonable warnings for products sold in the future, and pay an appropriate civil penalty based on violations.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.