(CNN) The year was 2004, and James Monsees and Adam Bowen couldn't stop taking smoking breaks during a brainstorming session for their joint master's thesis at Stanford University's design school. It was during one of these breaks that they decided: Why not create a better way to deliver nicotine?
Eleven years later, they unveiled Juul, a device that gives users a flavored nicotine fix without the smell and smoke of combustible cigarettes. It's an e-cigarette, which means it doesn't burn tobacco but rather generates an aerosol by heating a liquid that contains nicotine.
Juul, along with many other e-cigarette products, has found a place in a multibillion-dollar market. According to a Bloomberg report from late June, Juul controls 68% of the e-cigarette market. In 2016, 3.2% of US adults were current e-cigarette smokers while 15.5% smoked combustible cigarettes according to the National Health Interview Survey. Younger adults were more likely to vape than older ones.
That even holds true for underage users: Youths are more likely than adults to vape, according to the US Centers for Disease Control and Prevention. For high school and middle school students who used a tobacco product in 2016, e-cigarettes were the most commonly used; 11.3% of high schoolers and 4.3% of middle schoolers used e-cigs, according to data from the 2011-2016 National Youth Tobacco Surveys.
The act of vaping has even become a verb among youth: Juuling.
Today, Monsees and Bowen are the chief product officers for the company. Ashley Gould, the chief administrative officer for Juul Labs, said they designed Juul for adult smokers trying to switch from combustible cigarettes, but data show the product's startling popularity among youth.
"It's been devastating to us," Gould said. "This is not a product for youth. It's a product for adult smokers."
According to a 2017 national online survey by the Truth Initiative, a nonprofit tobacco control organization, 7% of teens 15 to 17 reported having ever used a Juul.
"The evidence is overwhelming today that these products appeal to kids," said Matt Myers, president of the nonprofit organization Campaign for Tobacco-Free Kids.
But Juul Labs argues that, by helping people give up cigarettes completely, the company provides a potentially life-saving service to current smokers, two-thirds of whom will die from smoking-related illnesses. The scientific consensus, however, is still out on the long-term health effects of vaping. And new research, combined with lawsuits against Juul Labs, threatens to undermine the company's argument.
"We need to talk to our kids, and at the same time, we can't forget about the 38 million American adult smokers in our country who need and deserve our support," Gould said.
New research on the health effects of vaping and lawsuits against Juul Labs threaten to undermine the company's argument.
At Jonathan Law High School in Milford, Connecticut, Principal Francis Thompson pulled from his pocket a sleek device resembling a USB drive. It's the Juul, the most popular vape students used, he said.
Vaping among teens took off so rapidly at Jonathan Law, the school had to take drastic measures.
"Being a relatively new phenomenon, we didn't know a lot about vaping and its impact and its danger and, quite frankly, its popularity that continues to rise among teenagers," Thompson said. "It was causing several issues in our school bathrooms."
Thompson closed all but one of the school's bathrooms. But then, kids began to brazenly vape in hallways and classrooms instead, recalls Andrew Paulus, an 18-year-old recent graduate.
"It was a party setting. I saw everyone was doing it, so I was like, 'Let me just try it once just to see what this fuss is about,' " Paulus said.
Emma Hudd, one of Paulus' classmates, said that teachers who didn't know any better would allow kids to plug their vapes into classroom computers to charge them.
Hudd, 18, likened Juul to her generation's version of cigarettes.
"We need to understand this more, because no usage of our product by youth is acceptable to us," Gould said.
"I can tell you certainly though, it was not designed to look like a USB device. It was not designed to be hid by kids," she said. "This is a product that was designed by smokers for adult smokers, and that is the design ethos of the product."
Bella Kacoyannakis saw the Juul on social media sites, where people would post about how "awesome" it was, she said. The first time the 20-year-old tried it, she said she was immediately drawn to its small size, simple upkeep and fruity flavors.
"I like the Juul better than cigarettes because the taste is so much more pleasant. And, like, the nicotine content isn't really that much different," Kacoyannakis said.
The nicotine in one Juulpod, a small disposable e-liquid cartridge that's inserted into the vaping device, is equal to that of an entire pack of cigarettes, according to the company. The rate at which a Juulpod is consumed varies among users, but can last about 200 puffs.
Since Kacoyannakis switched from cigarettes to the Juul, she says, she vapes more than she used to smoke because of how convenient the device is.
Gould said the company's data do not show that Juulers who switched from cigarettes are taking in more nicotine than they did when they smoked. Independent research hasn't yet confirmed Juul Labs' data.
Kacoyannakis recently picked up the box of her Juul and for the first time read the warning label.
"This product contains chemicals known to the state of California to cause cancer and birth defects or other reproductive harm," she read aloud. She had never noticed the California Proposition 65 warning before.
Neither had Paulus or his friends.
"On the front [of the packaging], it's big letters, J-U-U-L Juul, or it has the flavoring in the color of the pod, but no one really looks at the side to see this really small writing saying, 'Oh, caution, this is bad for you or whatever,' " he said.
The Truth Initiative survey reported that 63% of young Juul users did not know that the product always contains nicotine.
Gould said Juul Labs has added larger warning labels that now announce that the product contains nicotine across 20% of the space showing on a package.
Nicotine isn't the only ingredient in e-cigarettes, though. Studies from Harvard and Johns Hopkins researchers found that e-cigarette users wind up inhaling dangerous chemicals and toxic heavy metals along with their nicotine fix.
"There's a lot that's happening with an e-cigarette besides just the nicotine and the carrier fluid. You're also inhaling these flavoring chemicals like diacetyl or cousins of diacetyl, which have been found to be harmful," said Joe Allen, an assistant professor at the Harvard T.H. Chan School of Public Health and the first author of a study on the presence of diacetyl in e-cigarettes.
Much of what's known about diacetyl's effects on the lungs comes from studying the workers in a microwave popcorn packaging plant, Allen said. Twenty years ago, these workers developed a disease called bronchiolitis obliterans, or popcorn lung, after inhaling the fumes of artificial butter flavoring from open vats in their workplace.
"You see a slow onset of some symptoms like wheezing, shortness of breath or coughing," Allen said. "This is a disease that is irreversible, often requiring a lung transplant."
But David Abrams, a professor at the NYU College of Global Public Health who has researched smoking cessation for 40 years, doesn't see diacetyl inhalation as much of a threat for vapers.
"I think this whole story of diacetyl and popcorn lung, which is true only in popcorn workers who were exposed for eight to 10 hours a day has been completely exaggerated, and it's part of what's led the public into thinking e-cigarettes are as dangerous as cigarettes," he said.
Nevertheless, Abrams said the public can't be reassured completely until the US Food and Drug Administration regulates vaping products.
Last year, the FDA announced that it would delay regulations that could have halted the sales of many e-cigarettes. Instead, the agency gave extensions to new and existing vaping products, giving them until August 2022 to submit information to support their products' safety and efficacy as switching devices.
The organization decided on this timeline to "make certain that the FDA is striking an appropriate balance between regulation and encouraging development of innovative tobacco products that may be less dangerous than cigarettes," according to the news release announcing the extensions.
Michael Felberbaum, an FDA spokesman, said the agency does not have any additional information regarding a regulatory timeline once these applications are submitted. Meanwhile, the agency plans to propose a series of product standards to address some of the known public health risks of these products, which includes taking a close look at flavors, he said.
Greg Conley, president of the American Vaping Association, said the question facing the American public and the FDA is not whether there should be regulations but whether they should be so strict as to wipe out competition from independent vape companies.
"Reasonable product standards that actually help make the products better, help instill consumer confidence, that would be fine," he said. "But what the FDA has proposed is not regulation; it is prohibition for 99% of products on the market today."
Gould says reasonable regulation would entail banning candy flavoring for e-cigs like cotton candy and gummy bear, cracking down on marketing to youth and restricting purchase to buyers 21 and older.
Even as it announced the extensions last year, FDA Commissioner Dr. Scott Gottlieb said the agency would "redouble our efforts to protect kids from all nicotine-containing products."
Felberbaum said the agency's goal is to balance public health concerns alongside the innovation of the e-cigarette industry, which "can't come at the expense of kids," he added.
In April, after telling CNN Chief Medical Correspondent Dr. Sanjay Gupta that the organization would be taking enforcement actions "very soon" against companies believed to be marketing products to young people, Gottlieb announced a "blitz" on retailers for violations related to sales of e-cigarettes to minors. The agency said it sent Juul Labs a request to submit documents related to product marketing and research, including information about "youth initiation and use."
In July, the company was hit with multiple lawsuits that allege Juul Labs intentionally targets teens in its marketing. Prior to the lawsuits, Gould said the company took seriously the criticism of its 2015 launch campaign, which used young-looking models. The company had also announced that it would no longer use models on social media platforms, instead focusing on testimonials from adult smokers who switched to Juul.
"That campaign in the end, we felt, did not help us achieve our mission of speaking to adult smokers to provide them information about an alternative to cigarettes," she said.
Juul uses age verification measures on its website, but Gould said 90% of the company's sales are at the retail level, which is more difficult to regulate.
Paulus, the recent high school graduate, says enforcing stricter age laws won't stop underage users from getting their hands on Juuls.
"I'm 18, and a freshman, sophomore, junior -- if they really want to smoke or use a Juul, they could ask me or ask anyone in the senior class that's over 18, and they could easily just give them money, go to a store, pick it up for them," he said.
Other approaches target the schools where the Juuling problem is prevalent.
One independent organization that has developed an e-cigarette prevention program for middle and high school students is the Coordinated Approach to Child Health, or CATCH. It includes four lessons with topics that include e-cigarette ingredients, marketing techniques and skills for refusing e-cigarettes.
Ashley Monteiro, a student at Wareham Middle School in Massachusetts, said that before taking the class, she thought e-cigarettes looked "pretty cool" and the flavors might taste good. But since learning about the use of artificial flavorings and chemicals in vapes, she's no longer interested.
For Hudd, a 2018 grad of Jonathan Law High School, the solution to the vaping craze is to escape its epicenter.
"I'm happy I'm leaving high school so that I can get out of here and away from all the Juuling," she said.