Women smoke in a Moscow bar in May. Tough new anti-smoking rules took effect Sunday in Russia, banning smoking in bars, restaurants and other public spaces. Alexander Utkin/AFP/Getty Images hide caption

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Some employees say e-cigarettes increase their productivity and help them steer clear of tobacco. But health regulators are looking into possible risks to e-cig users — and to co-workers. iStockphoto hide caption

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Electronic cigarettes are actually battery operated devices that use a heating element to atomize a flavored liquid, typically containing nicotine, so that it can be inhaled. Joe Raedle/Getty Images hide caption

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New York City Mayor Michael Bloomberg holds a 64-ounce cup, as Lucky's Cafe owner Greg Anagnostopoulos stands behind him during a news conference at the cafe in New York. Seth Wenig/AP hide caption

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