The U.S. Food and Drug Administration proposed rules on Thursday that would ban the sale of e-cigarettes to anyone under 18, but would not restrict flavoured products, online sales or advertising, which public health advocates say attract children.

The long-awaited proposal would subject the $2 billion US e-cigarette industry to federal regulation for the first time.

FDA commissioner Margaret Hamburg said at a briefing that the proposal represented the first "foundational" step towards broader restrictions if scientific evidence shows they are needed to protect public health.

Critics of e-cigarette advertising say it risks introducing a new generation of young people to conventional cigarettes when little is known about the long-term health impact of the products. And they lamented the fact that limits were not included in the proposed rule.

"It's very disappointing because they don't do anything to rein in the wild-west marketing that is targeting kids," said Stanton Glantz, a professor at the Center of Tobacco Control Research and Education at the University of California San Francisco. "They should not have been so timid."

FDA Electronic Cigarettes

Eric Scheman demonstrates an e-cigarette at Vape store in Chicago on Wednesday. The U.S. government wants to ban sales of electronic cigarettes to minors and require approval for new products and health warning labels. (Nam Y. Huh/Associated Press)

Hamburg said the current proposal "lays the foundation for many more actions and activities."

Vince Willmore, a spokesman for the Campaign for Tobacco Free Kids, said the proposal "by no means does everything we think needs to be done, but it starts the process. What is critical now is that they finalize this rule and then move quickly to fill the gaps."

Likewise in Canada, the Non-Smokers' Rights Association called the proposed U.S. moves a step in the right direction. 

"Right now, we have e-cigarettes being advertised and promoted in all the same ways that tobacco products were and that is one of the main risks we think to promoting e-cigarette use, nicotine addiction and possibly even cigarette addiction amongst youth is the re-normalization of smoking-type behaviours," said Melodie Tilson, director of policy for the Non-Smokers' Rights Association in Ottawa.

Ban on free samples proposed

A law passed in 2009 gave the FDA authority to regulate cigarettes, smokeless tobacco and roll-your-own tobacco and stipulated the agency could extend its jurisdiction to other nicotine products after issuing a rule to that effect. E-cigarettes use battery-powered cartridges to produce a nicotine-laced inhalable vapour.

'By not addressing the youth-directed marketing it means it won't be addressed for a very long time.'- Stanton Glantz

In the short term, the rule would prohibit companies from distributing free e-cigarette samples, forbid vending machine sales except in adult-only venues and prohibit sales to minors. Companies would be required to warn that nicotine is addictive, but no other health warnings would be required. The addiction warning would have to be added no later than two years after the rule is set. The companies would not be allowed to make health claims in any advertising.

The proposal is subject to a public-comment period of 75 days. Willmore said the FDA should aim to establish the rule within a year.

Some are skeptical that restrictions on marketing or flavors will come any time soon.

"The reality of these things is that every step takes years," said Glantz. "By not addressing the youth-directed marketing it means it won't be addressed for a very long time."

Evolving 'vaping' industry

Some e-cigarette companies that sell primarily through convenience stores were surprised at the lack of restrictions on online sales, since it can be difficult to verify a customer's age over the internet.

"The internet thing is very surprising to me," said Miguel Martin, president of Logic Technology, one of the biggest e-cigarette manufacturers. "It reduces the visibility of the sales of the products and the type of products that the government has awareness of."

The rules would require companies to submit new and existing products to the FDA for approval. They would have two years to submit applications from the time the rule goes into effect. Companies may continue selling their products and introducing new products pending the FDA's review.

In the meantime, they would be required to register with the FDA and list the ingredients in their products. They would not be required to adhere immediately to specific product or quality control standards. That could come later, Hamburg said.

Canadian regulations

E-cigarettes and other "vaping" devices generate roughly $2 billion a year in the United States, and some industry analysts expect their sales to outpace the $85-billion conventional-cigarette industry within a decade.

Advocates of e-cigarettes claim they are a safer alternative to conventional cigarettes, since they do not produce lung-destroying tar. But there is little data about their long-term safety.

Health Canada said in an email that it is monitoring the actions of other regulators and "considering all options for appropriate oversight of these products."

"Health Canada reminds Canadians that e-cigarettes with nicotine or e-cigarettes with a health claim are not authorized for sale in Canada," a spokeswoman said in an email.

"To date, there is not sufficient evidence that the potential benefits of e-cigarettes in helping Canadians to quit smoking outweigh the potential risks. A company would have to provide evidence of safety, quality and effectiveness in order to have its product authorized. Without this scientific evidence, Health Canada continues to advise Canadians, especially youth, against the use of these products."

The Nova Scotia government said it is looking for guidance from Health Canada before the province introduces legislation in the fall. Nova Scotia Health Minister Leo Glavine is concerned about what may be in the "juice" of e-cigarettes. 

"These are showing up in schools because they're not illegal," said Glavine. "So our legislation will bring e-cigarettes under the Smoking and Public Places Act and so that will be restrictive and also in terms of if there's approval in Canada for sales, they would not, of course, be able to be sold to minors."

Daniel David, a spokesman for the Electronic Cigarette Trade Association, said the FDA proposals should be adopted in Canada to make it clear to vendors that there are regulations to follow.

The FDA's proposal leaves many questions unanswered about how new products would be regulated over the long run. One key question relates to how products are approved.

Under current law, new tobacco products can be approved if they are "substantially equivalent" to a product that was on the market before Feb. 15, 2007. It is unclear whether any e-cigarettes were on sale before then, to be used as a benchmark.

Mitch Zeller, head of the FDA's tobacco division, said at a briefing that the agency would be seeking more information during the public-comment period on whether the "substantial equivalence" pathway is even valid for e-cigarettes.

If it is not, e-cigarette companies would have to use a different process, which would require them to prove their products are appropriate for public health, a higher hurdle to clear.

With files from CBC News