July 13 is the deadline for the Food and Drug Administration’s approval process on synthetic nicotine products.

Any marketed product sold in U.S. stores, such as Puff Bars or other vaping products, will become illegal if they do not meet the requirements of the FDA’s health and safety standards.

“Today, young people see vaping as cool. It was the kids who never would have smoked, and if you don’t get your arms around that fast, you’ll have another 30-year problem,” said Matt Myers, president of the Campaign for Tobacco-Free Kids.

In 2020, the FDA outlawed the sale of flavored tobacco products due to the number of kids it was enticing. According to a 2020 study from the Centers for Disease Control and Prevention, as many as 3 million high school students, or 19.6%, vape regularly, and 550,000 or 4.7% of middle schoolers do as well.

The law meant companies such as Juul, which controlled as much as 70% of the U.S. vaping market at the time, could only sell tobacco-flavored and mentholated tobacco products. Myers says the law was written in such a way that it allowed for loopholes. However, as other companies began creating synthetic nicotine that used no tobacco, which is why to this day, dozens of flavored vaping products are sold in convenience stores and gas stations nationwide.

“We’re really at a critical juncture both for e-cigarettes and in regard to youth cigarette use,” said Myers. “If the FDA follows through and removes from the market all of the flavored products that appeal to kids, we can reverse the youth e-cigarette epidemic in a relatively short period of time.”

The FDA does not have a clear list of vaping companies that have applied for approval and has not revealed if any have received it.

Advocates say what happens next weighs on if and how the FDA enforces its policy after July 13.

Related video above: Juul to pay $40M in teen vaping suit settlement

The U.S. Food and Drug Administration blocked the sale of more than 55,000 flavored e-cigarette products Thursday, its first ban of e-cigarette products since it began requiring makers to apply for premarket review last September.

The FDA issued marketing denial orders for the electronic nicotine delivery system (ENDS) products, saying they pose a public health threat to youth in the U.S. Of the more than 55,000 products impacted by the decision, those not yet being sold may not be introduced into the market, and those already on the market must be removed or risk enforcement.

Advocates complained the action did not cover big name products such as Juul, but the agency said more decisions are coming.

"Ensuring new tobacco products undergo an evaluation by the FDA is a critical part of our aim to reduce tobacco-related disease and death," said Acting FDA Commissioner Dr. Janet Woodcock. "We know that flavored tobacco products are very appealing to young people, therefore assessing the impact of potential or actual youth use is a critical factor in our decision-making about which products may be marketed."

Though e-cigarette products are often marketed as tools to help adults quit smoking cigarettes, health experts have been sounding the alarm for years over an alarming uptick in use among children and teens.

U.S. e-cigarette sales rose by nearly 300% between November 2016 and August 2019, according to the U.S. Centers for Disease Control and Prevention. Nearly 20% of high schoolers and almost 5% of middle schoolers reported using vape products in 2020, according to research published in the journal JAMA Network Open.

Many point to the sweet flavors and flashy packaging of these products as proof that companies know exactly who they are marketing to.

The non-tobacco, flavored e-cigarette products impacted by Thursday's decision -- which include flavors, like Apple Crumble, Dr. Cola and Cinnamon Toast Cereal -- are made by three companies: JD Nova Group LLC, Great American Vapes and Vapor Salon.

Matthew Myers, president of the Campaign for Tobacco-Free Kids, said the decision is a step in the right direction, but does not go far enough.

"The FDA's action covers just a fraction of the more than 6.5 million tobacco products for which the FDA has received marketing applications, and it does not include any e-cigarette brands with a significant market share or that are most popular with kids, such as Juul, the number one youth brand," Myers told CNN in a statement.

The FDA said it's making its way through those applications, submitted by 500 companies by the September 2020 deadline for deemed new tobacco products to apply for pre-market review.

The agency is tasked with determining whether these products "have a benefit to adult smokers sufficient to overcome the public health threat posed by the well-documented, alarming levels of youth use of such products."

"Flavored ENDS products are extremely popular among youth, with over 80% of e-cigarette users between ages 12 through 17 using one of these products," said Mitch Zeller, director of the FDA's Center for Tobacco Products. "Companies who want to continue to market their flavored ENDS products must have robust and reliable evidence showing that their products' potential benefit for adult smokers outweighs the significant known risk to youth."

In February 2020, the Trump administration enacted a "flavor ban," establishing that the Food and Drug Administration would prioritize enforcement against flavored, cartridge-based vaping products.

Because disposable vapes, some e-liquids, and tobacco and menthol-flavored products were exempted from the policy, health experts expressed concern that it would simply redirect users to those available products.

"In 2020, over one million middle and high school students used menthol e-cigarettes, including 44.5% of youth who used flavored, pre-filled cartridge products like Juul," Myers said.

The FDA's decision is "not a substitute for comprehensive action to eliminate all flavored e-cigarettes, including menthol-flavored products that are popular with and widely used by kids," he added.

The FDA noted the scientific review of menthol e-cigarettes, as opposed to other non-tobacco flavored e-cigarettes, raises "unique considerations."

While menthol products were not included in Thursday's decision, the FDA's evaluation of those applications will consider the same question: Does the benefit to adult users outweigh the risk to youth?

Related video above: Nearly Half Of American Teens Who Vape Want To Quit

It was a pivotal public health crisis in America before the COVID-19 pandemic -- and then we stopped talking about it.

E-cigarettes became ubiquitous in high schools across the country, resulting in scores of teens addicted to nicotine. And though industry leader Juul Labs denied that was ever its intent, the company landed front-and-center in a heated debate.

In recent years, Juul, which once held the majority of the U.S. e-cigarette market, has been embattled in a deluge of lawsuits and investigations into its products' appeal to kids. The company says it's engaged in an "ongoing effort to reset our company ... as we continue to combat underage usage and advance the opportunity for harm reduction for adult smokers."

But Juul's products are just a few among millions that are now in regulatory limbo with the U.S. Food and Drug Administration. And this fall could bring decisions that some experts say are long overdue.

What happens next

E-cigarette products have been allowed to remain on the market for years, even though none have been given the official green light by the FDA. But a key deadline is looming.

Previously, a July 2019 court decision placed a 10-month deadline on e-cigarette companies to apply to the FDA for public health review. Any products that missed the May 2020 application deadline could have been pulled from the market by the FDA, while those that did apply could stay on the market for up to a year while under review.

Then came COVID-19 -- and a four-month extension of that deadline to Sept. 9, 2020.

"Nine months have now passed since that September 2020 deadline and we have received thousands of submissions for millions of new tobacco products," said FDA's acting commissioner, Dr. Janet Woodcock, in congressional testimony late June.

More than 550 companies have now submitted over 6.5 million tobacco products to the FDA, all but a sliver related to e-cigarettes. Juul has submitted applications for just five of those products.

According to Woodcock, most of the products in the regulatory pathway known as PMTA -- or Premarket Tobacco Product Applications -- are evaluated in a random order, using computers to line up candidates. But in this case, with so many products in the pipeline, the FDA has carved out a separate queue for those that "account of the vast majority of the current market," she said.

An FDA spokesperson told CNN in an email that the agency is "working to review applications as quickly as possible. However, given the unprecedented number of applications ... the likelihood of FDA reviewing all the applications by Sept. 9, 2021, is low.

"With that being said, as with all unauthorized products generally, if products are not authorized by September 9, 2021, and do not come off the market at that time, they risk FDA enforcement."Experts say the outcome is far from preordained.

Unlike some product reviews whose only data comes from research trials, in this case there's plenty of real-world experience, according to Matthew L. Myers, president of the Campaign for Tobacco-Free Kids.

"At this point, I think all of us are speculating and reading tea leaves," he said.

Myers called for more transparency surrounding the authorization process and believes the FDA's actions on e-cigarettes "will, over the long term, define how FDA is perceived."

Until those decisions are announced, health and industry advocates alike are keeping a close eye on market leaders like Juul as a potential harbinger of what's to come.

Gregory Conley, president of the American Vaping Association, said "the agency's views on Juul's menthol flavor, nicotine levels, and its embrace of strict marketing controls is absolutely something that the rest of the industry will be watching."

Following suit

"After a long, relatively quiet period, things are really heating up," said Dr. Robert Jackler, founder of the Stanford Research into the Impact of Tobacco Advertising.

For Juul, it's not just about awaiting the FDA's decision, but also addressing a number of lawsuits against the company. For one, Juul recently agreed to pay $40 million to settle a two-year-old lawsuit with North Carolina -- the first state lawsuit that alleged it marketed to teens.

The company said the settlement was consistent with its "reset" -- one that goes back to late 2019 after a change in leadership. Under a new CEO, K.C. Crosthwaite, Juul took a number of actions that included removing flavored products from the market and scaling back its advertising and lobbying efforts. (Crosthwaite was a former executive of Altria, a tobacco company which in late 2018 had purchased a 35% stake in Juul, worth $12.8 billion.)

In an email to CNN, a Juul spokesman described the company's efforts more broadly to "reset the vapor category" in the US by working with officials toward its goals of "transitioning adult smokers away from cigarettes, eliminating their use, and combating underage usage of our products."

In an earlier statement, Juul described the North Carolina settlement is "another step in that direction."

Jackler says the settlement, to be paid over six years, may not be a huge financial blow to a large company, but the implications could be much broader.

"I think it's informative that Juul chose to settle rather than take the risk of facing a jury right in the heart of tobacco country," he said.

Jackler pointed back at the '90s, when Mississippi became the first in a series of states to file suit against major tobacco companies. He described the initial settlement with Mississippi as "relatively modest, but it was the first of a cascade of things." Most notably: the 1998 Master Settlement Agreement, which awarded a total of more than $200 billion to states.

How a potential green light from the FDA could impact ongoing litigation is unclear. Instead, that review hinges on a pivotal question: What is a product's impact on public health?

Ongoing debate

In deciding whether to green-light certain vaping products, the FDA must decide their public health merit. Does the likelihood of smokers switching over to vapes outweigh the likelihood that others -- especially young people -- will start getting hooked on nicotine

This is why the agency's PMTA review focuses not only on things that come with the product itself -- like ingredients, toxicology, manufacturing, packaging and labeling -- but also on the "net public health impact of individual products at a population level," according to the FDA spokesperson."

For e-cigarettes, that includes considering uptake by our nation's youth, possible benefits of decreased use of combustible tobacco products by adults, the potential negative health effects of dual use of both e-cigarettes and combustible cigarettes, and the possibility that e-cigarettes could be a 'gateway' product to combustible cigarettes for youth," the spokesperson said, adding that any decisions we see this fall may not be the final word.

"Following any authorization, if the FDA determines that a product is no longer appropriate for the protection of public health, the agency has authority to take regulatory action, which could include withdrawing the marketing order."

Cigarette smoking has been estimated to cause more than 480,000 deaths per year in the U.S. In allowing e-cigarettes to remain on the market, former FDA Commissioner Dr. Scott Gottlieb had said he wanted to leave the door open for adults who might use these products to quit smoking cigarettes.

Indeed, there is some evidence that adults who vape are more likely to quit cigarettes. Still, certain findings have also faced concerns that many adults become "dual users" — not quitting entirely but potentially smoking less, at least temporarily.

Even given the potential benefit to some smokers, "it can't come at the expense of addicting a generation of kids on nicotine," Gottlieb told CNN in late 2018.

The use of e-cigarettes among young people declined significantly from 2019 to 2020 but remains high. Nearly 20% of high schoolers and almost 5% of middle schoolers reported last year that they currently vaped -- down from 27.5% and 10.5% in 2019. Most adolescent users have also reported using flavored products.

Data also show that disposable vapes are also on the rise among high schoolers who vape, growing from 2.4% in 2019 to 26.5% in 2020. These e-cigarettes are different from Juul's, wherein only the pod is replaced. And they come in a variety of sweet and fruity flavors that FDA no longer allows in prefilled cartridges.

That may be one reason why kids are increasingly using disposable vapes, while Juul use has gone down. As one study puts it, "significant declines in [youth] use of the JUUL brand were countered by significant increases in use of other vaping brands."

While flavors have come under scrutiny for their appeal to kids, proponents argue they can still be a useful tool in helping adult smokers quit. The FDA's enforcement currently exempts tobacco and menthol in pre-filled cartridges -- the two flavors that Juul has kept on the U.S. market and are included in its applications to the FDA.

Another debate swirls around leaving menthol on the market, which critics said amounted to "watering down the flavor ban" announced by the Trump administration in January. In April, the FDA also announced it was taking steps to ban menthol-flavored cigarettes and all flavored cigars within the next year.

Between a potential menthol ban and the FDA's consideration of lowering nicotine levels in cigarettes "to minimally addictive or nonaddictive levels," Conley of the American Vaping Association said "we remain hopeful that the FDA will recognize that if these product standards are to benefit public health, current adult smokers need effective smoke-free products to switch to."

Before and after

Juul may not dominate the market like it once did, but it continues to take heat for earlier business and marketing practices -- practices which later surfaced among a flurry of companies that have popped up in the years since.

Before Juul pared down its U.S. products to tobacco and menthol, it came in flavors such as mint, mango and crème brûlée. The company also released pods in concentrations up to 5% nicotine at a time when most competitors came in 1% to 2%. A number of companies boosted their own concentrations to mirror Juul's success, according to Jackler's research.

By combining nicotine -- a bitter base in its natural form -- with an organic acid, vape manufacturers like Juul have produced a "nicotine salt," masking nicotine's naturally unpleasant taste and creating higher-concentration products.

Juul, which also sells 3% nicotine pods in the U.S., has maintained that a 5% pod is designed to replace one pack of cigarettes in terms of the number of puffs and the nicotine strength. Nicotine concentrations are capped at lower levels in other countries, but no such limit exists in the U.S.

The company's early marketing and social media campaigns were widely criticized for their popularity among teens -- with user-generated Juul-related Instagram content continuing months after the company shut down its own social media accounts in late 2018.

Now, a number of newer companies have continued in that vein, with some catching the attention of federal agencies. Jackler's own research last year highlighted how companies "exploited" the pandemic to sell their products, he previously told CNN.

Juul may not be directly responsible for these ads, but critics say the company's ripple effect is still being felt — even if the broader vaping debate isn't quite in the spotlight.

"We haven't moved past this," Dorian Fuhrman, co-founder of the group Parents Against Vaping e-cigarettes, told CNN's Chris Cuomo last week. "[Juul] created a sexy new nicotine delivery system. And the kids flocked to it about five years ago. And this is personal to me."

Fuhrman's son, Phillip, became addicted to the company's products when he was 14.

"We have a whole generation of kids who would have never vaped, they would have never smoked cigarettes, and now we have a generation of nicotine addicts," Fuhrman said.