Oct 12 (Reuters) - The U.S. Food and Drug Administration (FDA) on Tuesday authorized e-cigarette products for the first time ever, allowing their sale by a unit of British American Tobacco Plc (BAT) (BATS.L) in the United States. It cleared the company"s Vuse Solo e-cigarette and the accompanying cartridges to be used for refills. However, the agency denied marketing authorization for certain flavored products submitted under unit R.J. Reynolds Vapor Co"s Vuse Solo brand for failing to demonstrate they would appropriately protect public health. E-cigarettes vaporize a nicotine-laced liquid, and their use among teenagers has been soaring, with health regulators bearing down on manufacturers for marketing to youth. In September, the FDA delayed its decision on whether Juul and other major manufacturers including BAT can sell their products in the United States, as it weighs the public health impact of the products. Data from a 2021 survey indicated that an estimated 2.06 million U.S. middle and high school students are using e-cigarettes, with Puff Bar, Vuse and Juul among the most popular brands. Most users said they used flavored products, with fruit, candy and desserts among the most common. read more The agency said the survey data reinforces its decision to authorize the tobacco-flavored products as they are not as popular among the youth. "The manufacturer"s data demonstrates its tobacco-flavored products could benefit addicted adult smokers who switch to these products – either completely or with a significant reduction in cigarette consumption – by reducing their exposure to harmful chemicals," Mitch Zeller, director of the FDA"s Center for Tobacco Products, said in a statement. Juul and Vuse have only sold tobacco and menthol flavors in the United States for nearly two years. The FDA on Tuesday also imposed strict digital, radio and television advertising restrictions on R.J. Reynolds. Juul did not immediately respond to a Reuters request for comment.