The electronic cigarette industry is booming, with sales doubling annually since 2008 and revenue expected to reach at least $1.5 billion this year.

But concerned that children and teens have easy access to the battery-powered inhalers, the Food and Drug Administration is considering strict new rules in the coming weeks that would treat the nicotine inhalers in much the same way as traditional cigarettes.

"E-cigarettes" use a heater that vaporizes a mixture typically composed of liquid nicotine, propylene glycol and other chemicals, although some products contain no nicotine. Since they don't burn tobacco, the FDA doesn't regulate them in the same way as traditional smokes.

Most researchers say e-cigarettes are safer than traditional cigarettes because tobacco isn't ingested into the lungs and they don't produce second-hand smoke, although few studies have been conducted on their long-term health risks.

Federal law prohibits the sale of tobacco cigarettes to anyone under 18, but there is no such restriction for e-cigarettes. And with no advertising restrictions and the products coming in an array of flavors such as bubble gum, strawberry and chocolate, critics say the devices increasingly are becoming popular with teens and children.

But a 2010 court decision ruled that e-cigarettes and other products made or derived from tobacco can be regulated as "tobacco products" under the Family Smoking Prevention and Tobacco Control Act, a 2009 law aimed at curbing the use of tobacco by minors.

The FDA won't say specifically what rules it is considering, but there is widespread speculation they may include age restrictions and bans on TV advertising and Internet sales.

The National Association of Attorneys General has pushed the FDA to regulate e-cigarettes, accusing the industry of covertly marketing the product to minors and pressing the agency to respond.

A dozen Democratic members of Congress have asked nine e-cigarette manufacturers to respond to accusations that they market their products to minors.

"E-cigarette manufacturers appear to be applying marketing tactics similar to those used by the tobacco industry to hook a new generation of children," the lawmakers said in letters to the companies.

The Centers for Disease Control and Prevention in September released a report showing e-cigarette use doubled among U.S. middle and high school students in 2011-12, resulting in an estimated 1.78 million students using the devices.

Some e-cigarette manufacturers support age limits for their products. But the industry has been increasingly aggressive in marketing its inhalers, including distributing free samples at bars, sporting events and over the Internet.

And while e-cigarette sales make up less than 2 percent of the annual $90 billion overall U.S. tobacco market, analysts estimate sales will jump to $5 billion to $10 billion with the next five years.

Lorillard, which claims about 40 percent of the e-cigarette market, has pressed the FDA not to lump e-cigarettes with traditional smokes, warning such a move would discourage traditional cigarette smokers from switching to less harmful e-cigarettes.

"A one-size-fits-all policy that treats e-cigarettes similarly to tobacco cigarettes could only result in e-cigarette consumers returning to traditional cigarettes — which simply doesn't make sense from a public health perspective," said Lorillard Chairman and Chief Executive Murray Kessler in a September letter to USA Today.