5 Things You Need to Know About E-Cigarettes

The electronic cigarette was invented in the 1960s, but it didn't really take off until a decade ago. Currently, there are more than 250 brands of "e-cigarettes" available in such flavors as watermelon, pink bubble gum and Java, and in more colors than the iPhone 5C.

The Tobacco Vapor Electronic Cigarette Association estimates about 4 million Americans now use battery powered cigarettes. They project sales of the devices to cross the 1 billion mark by the end of this year. Here, a look at the e-smoke trend, the good, the bad and the unknown.

What are e-cigarettes?

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.

How much do they cost?

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

Are e-cigarettes regulated?

The decision in a 2011 federal court case gives the Food and Drug Administration 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 has hinted it will begin to regulate e-smokes as soon as this year but so far, the only action the agency has taken is issuing a letter in 2010 to electronic cigarette distributors warning them to cease making various unsubstantiated marketing claims.