U.S. Surgeon General Jerome M. Adams on Tuesday declared e-cigarette use among kids an "epidemic" in the U.S., pointing to companies like Juul as problematic.

Adams held up a Juul e-cigarette device and a Juul nicotine pod during a news conference when explaining how new products have entered the market that most parents wouldn't recognize as something their children are using to inhale nicotine.

"We already have a half-century showing us evidence-based strategies that work to prevent youth tobacco use," Adams said. "However, the times have changed, and so must we. It's critical that we now apply these proven strategies to e-cigarettes, including USB flash drive-shaped products, such as Juul, the product I just showed you."

Juul has dominated the e-cigarette market since launching in 2015. It now represents about 75 percent of the market, according to Nielsen data, with much of the growth coming over the past year. The company says its e-cigarettes are meant for adult smokers who want to continue using nicotine without all the harm that comes with combustible cigarettes. However, Juul has become popular among young people, including teenagers.

"JUUL Labs shares a common goal with the Surgeon General and other federal health regulators — preventing youth from initiating on nicotine. We are committed to preventing youth access of JUUL products," the company said in a statement.

Federal data proved anecdotal reports from parents and teachers sounding the alarm about teens using Juul were accurate. The number of high school students who reported being current e-cigarette users, meaning they used the product within the past 30 days, increased 78 percent between 2017 and 2018, according to the Centers for Disease Control and Prevention's National Youth Tobacco Survey. That equates to 3.05 million high school students, or 20.8 percent of this group.

Results from the National Institute on Drug Abuse's Monitoring the Future survey released Monday showed the increase in e-cigarette use among 10th and 12th graders was the largest year-over-year jump for any substance measured in the survey's 44-year history.

"The bottom line is this: In the data sets we use, we have never seen any substance used by America's young people rise this rapidly," Health and Human Services Secretary Alex Azar said Tuesday at the news conference. "This is an unprecedented challenge."

The Food and Drug Administration in November said it would limit where most flavored e-cigarettes could be sold, restricting them to adult-only stores or stores that include an adult-only section. Juul said it would remove the bulk of its flavored products from all stores and continue to sell them on its adult-only online shop. It outlined procedures and guidelines for some retailers to follow in order to resume sales.

Meantime, Juul is considering selling a significant minority stake in itself to Big Tobacco company Altria, a move that has already sparked backlash.