A retail industry group is encouraging convenience stores and gas stations nationwide not to sell electronic cigarettes to minors.

According to a position statement obtained by The Associated Press, the National Association of Convenience Stores says that, as a best practice, e-cigarettes should be treated just like other tobacco products.

The more than 151,280 convenience stores in the U.S. accounted for nearly $540 million in e-cigarette sales in 2013.

The battery-powered devices heat a liquid nicotine solution and create vapor that’s inhaled.

The fast-growing industry is awaiting regulation by the Food and Drug Administration, which will likely ban sales to minors.

In the meantime, more than two dozen states have laws prohibiting the sale of e-cigarettes to minors. Many of their makers already restrict sales to those under 18.

(AP)