E-cigarettes are under fire for not placing warning labels on products containing nicotine. | Photo: Vaping360.com Flickr/ Creative Commons

Nicotine causes reproductive harm, but electronic cigarettes containing nicotine do not carry chemical warnings mandated in California. That accusation comes from the Center for Environmental Health, an advocacy organization seeking legal action against manufacturers.

The group wants e-cigarette makers to post Proposition 65 warnings -- the same kind found on a wide range of consumer products -- on e-cigarettes and associated paraphernalia. Prop 65 requires products sold in California to warn consumers of carcinogens and chemicals that cause reproductive harm. It sent notices to nearly 40 companies on Thursday demanding they carry Prop 65 labels and threatened to file lawsuits unless the companies post labels, recall products already sold, and pay fees based on civil penalties, which can run as high as $2,500 a day per violation.

Charles Margulis, a spokesman for the group said the strategy is to get the companies to forego an expensive legal tussle by entering negotiations, and to secure agreements about marketing, labeling, and other things. The group wants to change how the products, in its view, appear to be marketed to children with sweet flavors, and are not packaged securely enough to be childproof, he said.

A judge is not likely to let the companies escape responsibility simply by adding Prop 65 warnings after the fact, Margulis added. "Courts are not amendable to companies trying to evade law by post-notice action," he said.

The warning letters come as e-cigarettes are under increasing fire from the media and government officials. Late last month, the state Department of Public Health issued a statement warning that e-cigarettes are toxic and addicting.

"E-cigarettes contain nicotine and other harmful chemicals, and the nicotine in them is as addictive as the nicotine in cigarettes," said the department's director, Dr. Ron Chapman. "There is a lot of misinformation about e-cigarettes. That is why, as the state's health officer, I am advising Californians to avoid the use of e-cigarettes and keep them away from children of all ages."

Calls to poison control centers in California related to e-cigarettes have risen from 19 in 2012 to 243 last year, and more than 60 percent of those calls involved children under 5, according to the health department.

Nationwide, teenagers vape more than they smoke tobacco, the department said. The California legislature is considering a bill to outlaw vaping wherever smoking is prohibited.

Recent studies have only fueled the debate over the health and safety of e-cigarettes. Vaping groups say research has been mischaracterized and anti-vaping groups say the studies demonstrate the danger of e-cigarettes.

Gregory Conley, a spokesman for the American Vaping Association, said the legal threats are unfair. "They're going after small companies trying to extort settlements out of them. If their true intent was truthful warning labels, they would send these letters without accompanying demands that go beyond Prop 65."

Companies selling nicotine-containing products should add Prop 65 labels to their products, Conley said. "But for most companies that receive these letters, that's probably where this issue should and does end," he said.