The Food and Drug Administration on Friday authorized menthol-flavored electronic cigarettes for adult smokers, the first time the agency has opened the door for vaping companies to sell non-tobacco flavored products.

The FDA cleared Njoy, a vaping brand recently acquired by tobacco giant Altria, to market four menthol e-cigarettes. But regulators also said it would review applications for authorization of flavored e-cigarettes on a case-by-case basis and that its actions apply on to Njoy’s four products.

In announcing its decision, the FDA said it found that menthol-flavored e-cigarettes can reduce the harms of traditional tobacco smoking. But the agency emphasized that it is not approving menthol vaping products, which would mean the FDA had determined a drug is safe and effective for its intended use. Instead, authorization by the agency only means Njoy has received regulatory approval to market its products to the public.

“We are a data driven agency and will continue to follow the science to inform our review of premarket tobacco applications,”  Matthew Farrelly, director for the FDA’s Center for Tobacco Products, said in a statement. “Based upon our rigorous scientific review, in this instance, the strength of evidence of benefits to adult smokers from completely switching to a less harmful product was sufficient to outweigh the risks to youth.”

The decision lends new credibility to vaping companies’ long-standing claim that their products can help blunt the toll of smoking, which is blamed for 480,000 U.S. deaths annually due to cancer, lung disease and heart disease.

Parent groups and anti-tobacco advocates immediately criticized the decision, which comes after years of pushing regulators to keep menthol and other flavors that can appeal to teens off the market.

“This decision could mean we’ll never be able to close the Pandora’s box of the youth vaping epidemic,” said Meredith Berkman, co-founder of Parents Against Vaping E-cigarettes. “FDA has once again failed American families by allowing a predatory industry to source its next generation of lifetime customers — America’s children.”

Youth vaping has declined from all-time highs in recent years, with about 10% of high schoolers reporting e-cigarette use last year. Of those who vaped, 90% used flavors, including menthol.

All the e-cigarettes previously authorized by the FDA have been tobacco, which isn’t widely used by young people who vape.

Njoy is one of only three companies that previously received the FDA’s OK for vaping products. Like those products, the menthol varieties come as cartridges that plug into a reusable device that heats liquid nicotine, turning it into an inhalable aerosol.

Njoy’s products accounted for less than 3% of U.S. e-cigarette sales in the past year, according to retail data from Nielsen. Vuse, owned by Reynolds American, and Juul control about 60% of the market, while hundreds of disposable brands account for the rest.

Most teens who vape use disposable e-cigarettes, including brands like Elf Bar, which come in flavors such as watermelon and blueberry ice.

The Njoy approval is part of a sweeping FDA review intended to bring scientific scrutiny to the multibillion-dollar vaping market after years of regulatory delays. Currently the U.S. market includes thousands of fruit- and candy-flavored vapes that are technically illegal but are widely available in convenience stores, gas stations and vape shops.

—The Associated Press contributed to this report.