( CNN ) -- At first glance , it looks like the real thing . It 's white , with a brown filter . When the tip glows red , a smoke-like puff follows . But this is not a typical cigarette -- it 's an `` e-cig . '' A what ? An electronic cigarette . When an e-cigarette user inhales , a battery inside warms liquid nicotine stored in a plastic filter . Makers of e-cigs tout their product as the first healthy cigarette , free of harmful chemicals and tar typically found in tobacco products . The only ingredient : pure liquid nicotine . `` Our product is comparable to the nicotine patch except people still get the oral fixation , which they love , '' explained Elicko Taieb , CEO of Smoking Everywhere , one of the largest distributors of electronic cigarettes . But the U.S. Food and Drug Administration considers e-cigs an unapproved new drug because of a lack of scientific proof that they 're safe or effective . The FDA is trying to halt importation of e-cigs , but is n't seizing products already being sold in the United States . `` The FDA has been detaining and refusing importations since at least last summer of these so-called 'electronic cigarettes , ' `` FDA spokesperson Rita Chappelle told CNN in a written statement . Watch Sanjay Gupta 's take on e-cigarette » . Smoking Everywhere is `` pretty sure '' the product is safe , based on laboratory testing in Europe , Taieb said . The company declined a CNN request to review safety reports . `` There are no ingredients in our e-cigs that can cause cancer . However , it is a pretty new product , so we are not 100 percent sure of the side effects at this point , '' Taieb said . `` But we have n't heard of any negative side effects yet , but we are pretty sure they are safe . '' Electronic cigarettes run on a battery . A person inhales an e-cig as he or she would a typical cigarette . When inhaled , the battery warms liquid nicotine stored in a plastic filter . The combination of heat and liquid creates the vapor or `` smoke '' puff when exhaled . Health experts say the idea of an electronic cigarette is a great alternative to tobacco smoke but more evidence is needed . `` Nicotine is not the thing in tobacco smoke that causes cancer , but inhaling pure nicotine may be dangerous , '' said Dr. Steven Schroeder , physician and smoking cessation expert at the University of California-San Francisco Medical Center . `` We have no clue what the health effects could be . '' Nicotine replacement therapies -- the patch or gum -- are safe and highly successful to help quit smoking . Tobacco smoke causes nearly 90 percent of lung cancer deaths , according to the American Cancer Society . `` If it is a choice between smoking tobacco product or a nicotine replacement -- of course , keep taking the nicotine , '' Schroeder said . `` It is a heck of a lot healthier than tobacco smoking . '' Developers of e-cigs echo the thought . `` We are n't claiming electronic cigarettes help you quit altogether , but I promise our product wo n't cause cancer . So no matter what way you look at it , it 's the healthier option , '' Taieb said . Smoking Everywhere sells thousands of electronic cigarettes a day in the United States , the company said . Most are sold online or in 100 mall kiosks across the states . The company , which gave samples of e-cigs to celebrities at this year 's Grammy and Oscar awards , said it expects that `` big-name '' actors will soon promote the product . U.S. sales are expected to double in 2009 . Sales of e-cigs have been on the rise in the United Kingdom , Switzerland , Sweden and Brazil for several years . The trend prompted the World Health Organization to issue a statement in 2008 calling for more safety testing . `` If the marketers of the electronic cigarette want to help smokers quit , then they need to conduct clinical studies and toxicity analyses , '' the statement said . The idea that that e-cigs may be a good tobacco smoke alternative in the future could hold true , the FDA and WHO acknowledged , but proof of the product 's safety must come first .
Electronic cigarettes do n't contain tar , other chemicals ; only liquid nicotine . Comment: FDA says safety not proved , has been refusing importations . WHO called for more safety testing in 2008 .