The Food and Drug Administration (FDA) banned e-cigarette maker Juul from selling its products in the U.S. Thursday, after years of concerns that the product is unsafe and a danger to teenagers.

“The agency has dedicated significant resources to review products from the companies that account for most of the U.S. market. We recognize these make up a significant part of the available products and many have played a disproportionate role in the rise in youth vaping," FDA Commissioner Robert Califf said in a statement.

The decision comes two years after reviewing company data, as Juul pursued an authorization to stay on the market. Some analysts said the decision could be appealed, during which time Juul could still sell its products.

The FDA originally sought to make a decision in September of last year, weighing whether or not Juul is safe and whether its marketing tactics, and flavorful cartridges, contributed to an increase in usage among youth.

E-cigarettes have been pitched as a safer alternative to traditional cigarettes purely due to the type of smoke emitted.

The FDA said as much in its decisions to authorize some companies' products, noting that "authorized products’ aerosols are significantly less toxic than combusted cigarettes."

But both traditional and vaping products use nicotine, an addictive substance, adding to concerns about youth addiction — which spiked after Juul came on the market.

That is why Juul came under scrutiny in 2019, after its marketing campaign touted vaping as safer, and a way to help transition off of traditional tobacco products. It was also cited for selling to underaged users — as young as in middle school — and its products have been linked to dizziness and seizures, as well as longer term negative impact on the lungs.

But the FDA said it was due to insufficient data of the health risks that it pulled the products.

"To date, the FDA has not received clinical information to suggest an immediate hazard associated with the use of the JUUL device or JUULpods. There is also no way to know the potential harms from using other authorized or unauthorized third-party e-liquid pods with the JUUL device or using JUULpods with a non-JUUL device," according to the statement.

Former FDA Commissioner Scott Gottlieb, who was in charge of the regulatory agency when the problem first came to light, said in 2018 that vaping was leading to a rise in use with teens.

"E-cigs have become an almost ubiquitous ? and dangerous ? trend among teens. The disturbing and accelerating trajectory of use we’re seeing in youth, and the resulting path to addiction, must end," he said then.