5 Things You Need to Know About E-Cigarettes

April 24, 2014— -- intro: The U.S. Food and Drug Administration announced this morning plans to regulate electronic cigarettes, requiring manufacturers to disclose product ingredients to the administration and put warning labels on the devices. However, there’s probably a lot you didn’t know about the controversial e-cigarette.

VIDEO: FDA Wants Warning Label on E-Cigarettes, Ban on Sales to Minors

For instance, e-cigarettes –- which now come in more colors than the iPhone 5C -– have been around since the 1960s. They’ve only started to take off in the last decade with more than 250 brands and flavors like watermelon, pink bubble gum and Java. An estimated 4 million Americans use them, according to the Tobacco Vapor Electronic Cigarette Association.

Click through for answers to more of your burning questions.

quicklist: 1 category: E-Cigarettes Explainedtitle: What are e-cigarettes?url:text: E-cigarettes are battery operated nicotine inhalers that consist of a rechargeable lithium battery, a cartridge called a cartomizer and an LED that lights up at the end when you puff on the e-cigarette to simulate the burn of a tobacco cigarette. The cartomizer is filled with an e-liquid that typically contains the chemical propylene glycol along with nicotine, flavoring and other additives.

The device works much like a miniature version of the smoke machines that operate behind rock bands. When you "vape" -- that's the term for puffing on an e-cig -- a heating element boils the e-liquid until it produces a vapor. A device creates the same amount of vapor no matter how hard you puff until the battery or e-liquid runs down.

quicklist: 2

category: E-Cigarettes Explainedtitle: How much do they cost?url:text: Starter kits usually run between $30 and $100. The estimated cost of replacement cartridges is about $600, compared with the more than $1,000 a year it costs to feed a pack-a-day tobacco cigarette habit, according to the Tobacco Vapor Electronic Cigarette Association. Discount coupons and promotional codes are available online.

Read more: E-Cigarette Sales to Hit $1 Billion

quicklist: 3category: E-Cigarettes Explainedtitle:Are e-cigarettes regulated?url:text:

Until today, e-cigarettes were uncontrolled by the government despite a 2011 federal court case that gave the FDA the authority to regulate e-smokes under existing tobacco laws rather than as a medication or medical device, presumably because they deliver nicotine, which is derived from tobacco.

The agency had hinted it would begin regulating them this year, but its only action against the devices to date was a letter issued in 2010 to electronic cigarette distributors warning them to cease making various unsubstantiated marketing claims.

This has especially worried experts like Erika Seward, the assistant vice president of national advocacy for the American Lung Association.

"With e-cigarettes, we see a new product within the same industry -- tobacco -- using the same old tactics to glamorize their products," she said. "They use candy and fruit flavors to hook kids, they make implied health claims to encourage smokers to switch to their product instead of quitting all together, and they sponsor research to use that as a front for their claims."

Dr. Richard Besser, ABC News's chief health and medical editor, said public health officials have been concerned that e-cigarettes could be a gateway to further tobacco use.