By John Kruzel
WASHINGTON (Reuters) -The U.S. Supreme Court on Wednesday largely backed the U.S. Food and Drug Administration's refusal to let two e-cigarette companies sell flavored vape products that regulators consider a health risk to youths.
The justices threw out a lower court's decision that the FDA had failed to follow proper legal procedures under a federal law called the Administrative Procedure Act when it rejected the applications by the companies, Triton Distribution and Vapetasia, to sell these nicotine-containing products.

Conservative Justice Samuel Alito authored the unanimous ruling.
The e-cigarette companies had argued that the FDA improperly assessed their applications under a regulatory standard that differed from published guidance the companies had relied upon.
"Affected parties may have come away with the impression that the agency would apply a less demanding standard of proof than is evident in the denial orders the FDA ultimately issued," Alito wrote.
Alito added that "in the end, we cannot say that the FDA improperly changed its position with respect to scientific evidence" and certain other guidelines.
Wednesday's ruling left unresolved the question of how harmful it was to the companies that the FDA failed to consider their proposed plans to restrict underage access and use of their products, and ordered the lower court to reassess that issue under a different legal standard.
The advocacy group Campaign for Tobacco-Free Kids hailed the Supreme Court's ruling, saying it "should encourage FDA to stay the course."
"Today's (Wednesday's) ruling is a major victory for the health of America's kids and efforts to protect them from the flavored e-cigarettes that have fueled a youth nicotine addiction crisis," the group said in a statement.
An FDA rule that took effect in 2016 under Democratic President Barack Obama deemed e-cigarettes to be tobacco products that, like traditional cigarettes, are subject to agency review under a 2009 federal law called the Tobacco Control Act. The law requires manufacturers of e-cigarette products to apply for authorization to sell nicotine vaping devices and e-liquids.
The agency over the years has approved only 34 flavored e-cigarette varieties, all tobacco or menthol flavored. It maintains that it has not categorically banned flavored e-cigarette products.
E-cigarettes of various flavors are still easily available despite being illegal.
To secure regulatory approval, e-cigarette companies must show their product would be "appropriate for the protection of the public health," meaning any health benefits - like helping traditional cigarette smokers transition to generally less-harmful vaping - must outweigh the risks of bringing the new product to market.
Eric Heyer, the lawyer for the e-cigarette companies, expressed disappointment in the court's ruling.
"Triton and Vapetasia continue to believe in the great harm-reduction potential of their products for cigarette smokers," Heyer said.
Triton Distribution and Vapetasia filed FDA applications in 2020 for products with flavors such as sour grape, pink lemonade and crรจme brulee, and names including "Jimmy The Juice Man Peachy Strawberry" and "Suicide Bunny Mother's Milk and Cookies" - offerings that critics have said were designed to appeal to minors. The FDA denied the Triton and Vapetasia applications as well as hundreds of others by various companies involving more than a million flavored vape products.
During December 2 arguments in the case, a Justice Department lawyer arguing for the FDA said the companies knew throughout the application process that the agency was concerned about the fact that flavors are attractive to youth and about the addictive nature of nicotine, a chemical dangerous to developing brains.
Heyer suggested during those arguments that President Donald Trump's administration could shift the U.S. government's approach to flavored vape products. Heyer alluded to Trump's vow during his presidential campaign to "save vaping," despite having supported a ban on flavored vaping products during his first term in office.
The FDA found that in 2020 nearly one in five high school students and almost one in 20 middle school students used e-cigarettes, making e-cigarettes "the most widely used tobacco product among youth by far."
Triton and Vapetasia in 2021 asked the New Orleans-based 5th U.S. Circuit Court of Appeals to review the FDA's denial of their applications. The full slate of 5th Circuit judges ruled 10-6 that the FDA had been arbitrary and capricious in violation of the Administrative Procedure Act.
Seven other federal appellate courts had sided with the FDA in similar cases.
The Supreme Court on November 25 declined to hear an appeal by RJ Reynolds and other tobacco companies of a lower court's ruling upholding graphic health warnings required by the FDA on cigarette packs.
(Reporting by John Kruzel; Editing by Will Dunham)