(CNN) Tobacco opponents and Juul executives are testifying on Capitol Hill this week during a two-day hearing on the company's role in "the youth nicotine epidemic," according to the House Oversight Subcommittee on Economic and Consumer Policy.
The hearing will scrutinize the leading vape company's marketing, health claims and relationship with Big Tobacco -- namely, tobacco giant Altria, which invested nearly $13 billion in Juul Labs late last year.
The list of attendees sets the stage for a heated clash over whether e-cigarettes should be subject to stronger regulation, weighing their potential benefit to adults who want to quit smoking against the risk that a generation of young people will become addicted to nicotine.
Democratic Rep. Raja Krishnamoorthi of Illinois, the chairman of the subcommittee, announced last month that his panel was investigating Juul, and asked the company to "provide memoranda and communications regarding its social media practices, advertising, and the product's long-term impact on consumer health."
"The safety and well-being of America's youth is not for sale," Krishnamoorthi said in a letter to Juul CEO Kevin Burns dated June 7. "I am extremely concerned about reports that JUUL's high nicotine content is fueling addiction and that frequent JUUL use is sending kids across the country into rehab, some as young as 15."
During the first day of the hearing, on Wednesday, committee members will hear from representatives of groups such as the American Academy of Pediatrics and Parents Against Vaping E-cigarettes. Other witnesses include experts such as Dr. Robert Jackler, founder of Stanford Research Into the Impact of Tobacco Advertising.
In research shared exclusively with CNN and now posted online, Jackler's team found that the amount of Juul-related content posted by Instagram users has exploded in the months since the company shut down its own social media accounts in November.
In the eight months since Juul phased out its social media, more than half a million Instagram posts have featured hashtags related to Juul, the paper says. That's double the number that had been posted in the three and a half years before Juul discontinued its accounts.
"Among #juul posts, 15.4% showed JUUL products, 28.1% JUUL competitors, and 3.7% products from both JUUL and its competitors," says the paper, which has not yet undergone peer review. "Reflecting the popularity of #juul as a gathering place for its largely youthful audience, non-vaping related posts made up the remaining 52.8%."
In a statement Wednesday, a Juul representative said "we strongly support Instagram fully banning #juul and implementing enhanced community standards to address inappropriate vaping content targeted at youth," adding that Juul has reached out to the social media company to discuss such policies in the past.
Earlier this month, in response to other research on Juul-related Instagram posts, Juul spokesman Ted Kwong cautioned against conflating the company's own posts with "wholly unaffiliated third-party content, including content from entities we are actively suing for their inappropriate and unauthorized activities."
"We agree these types of posts are a serious problem and that is why we employ a social media monitoring team dedicated to submitting takedown requests of exactly the type of inappropriate third-party social media content the authors cite as problematic," said Kwong at the time, adding that this team has resulted in the removal of "31,889 social media listings, including 25,405 individual Instagram posts, and an additional 1,251 Instagram accounts."
In Jackler's new paper, he also published examples of youth-oriented content on Instagram referencing Juul. Some posts included humor -- "I only suck juuls, sorry boys," one post reads -- while others took a more serious tone.
In one video archived by Jackler, a toddler is handed a Juul and proceeds to suck on it.
"It is striking how members of the community who post to #juul have few boundaries," Jackler said of the video, which was removed by Instagram on July 8 for violating its policies, according to a spokeswoman for the platform.
Jackler says both Juul and Instagram must do more.
When it comes to the social media site, Jackler said it could choose to ban the #juul hashtag under its community guidelines. The company has already banned some hashtags involving sexual references, slurs and other drugs, Jackler said.
For example, a search for #xanax yields no results on Instagram. A search for #juul yields more than 543,000 posts. There are a multitude of other hashtags containing "juul" as well.
A spokeswoman for Instagram's parent company, Facebook, said the platform blocks hashtags when it finds that hashtags are consistently being used to violate policies. The company banned #xanax, the spokeswoman said, because it found content on the hashtag seeking to sell the substance -- and the company doesn't allow the sale of pharmaceuticals or illicit drugs on the platform.
In an email, the spokeswoman also revealed a new policy starting Wednesday: "We will no longer allow the sale or purchase of tobacco products between private individuals."
Under the new policy, users can still post other kinds of content about tobacco and vape products. This includes users under age 18.
Individuals are also allowed to work as so-called influencers, compensated by tobacco and vape brands for promoting products, but Instagram said it was looking into possible changes in partnership with the wider industry.
During the second day of the hearing, on Thursday, Juul co-founder James Monsees and chief administrative officer Ashley Gould will testify. So will Matthew L. Myers, president of the Campaign for Tobacco-Free Kids and one of Juul's most outspoken critics.
In a statement Tuesday, a Juul representative said the company shares the committee's concerns about youth vaping and plans to discuss actions it has taken to keep its products away from kids -- including removing certain flavors from thousands of retail stores, improving its age-verification process online and getting "inappropriate social media content generated by others" taken down.
"We look forward to a productive dialogue as we continue to combat youth usage and help adult smokers switch from combustible cigarettes, which remain the leading cause of preventable death around the world," the statement said.
Also scheduled to attend is Sen. Dick Durbin of Illinois, one of 11 Democratic senators who sent a scathing letter to Juul in April demanding similar information related to the company's popularity among youth and its relationship with Altria.
The Altria deal signaled that Juul is "more interested in padding its profit margins than protecting our nation's children," says the letter, which was also signed by Sens. Ron Wyden of Oregon, Richard Blumenthal of Connecticut and Elizabeth Warren of Massachusetts.
Written testimony shared by the subcommittee ahead of Wednesday's session sheds light on what's to come.
"Every one of my teenage patients -- and even many of my preteen patients -- either uses e-cigarettes or has friends who use them," Dr. Jonathan Winickoff, speaking on behalf of the American Academy of Pediatrics, said in his written testimony.
"Many of my patients find JUUL nearly impossible to stop," said Winickoff, who is also the director of pediatric research at the Tobacco Research and Treatment Center at Massachusetts General Hospital.
He said that upcoming research of high schoolers in his state "found that daily JUUL and other e-cigarette use is much more likely to continue than daily smoking." And doctors lack effective tools to help kids quit, he added.
Meredith Berkman, co-founder of Parents Against Vaping E-cigarettes, advocated that flavors be taken off the market in her written testimony. She said parents like her came to a sudden realization that Juul had become a social norm among teens "seemingly overnight."
"How was it possible that there had been a teen cultural revolution and most adults hadn't even noticed?" she asks.
Representing the Cheyenne River Sioux Tribe, public health analyst Rae O'Leary said the company "targeted American Indians by exploiting tribal sovereignty, which will eventually negatively impact American Indian youth." O'Leary recounted a visit by Juul representatives earlier this year to offer the tribal council a "switching program" and free starter kits as part of an implied harm reduction effort and public health study.
O'Leary says the tribe was "unfairly exploited."
In recent communications, Juul says it cannot make claims that its products are safer than combustible cigarettes, in line with US Food and Drug Administration regulations.
Raymond Niaura, professor of social and behavioral sciences at NYU's College of Global Public Health, told CNN in an email that he plans to discuss recent evidence that e-cigarettes can help smokers quit, as well as data he said reflects "small" and "mostly experimental" uptick in vaping among teens who have never smoked. "However, I don't want to minimize the concern about youth vaping," he added.
Niaura, also interim chair of the college's epidemiology department, said "it is wrong to think that youth prevention should outweigh adult smoking cessation in terms of public health priority (or vice versa).
"We Americans should be smart enough to figure out how we can do both."