(CNN) The chairman of the House Oversight Subcommittee on Economic and Consumer Policy asked the US Food and Drug Administration in a letter on Thursday to take "appropriate enforcement action" against leading e-cigarette maker Juul.
Rep. Raja Krishnamoorthi, a Democrat from Illinois, said that the agency should "protect the American public from the fraudulent and unapproved medical claims" made by the company.
Krishnamoorthi's letter follows a two-day hearing in July, after which the committee concluded that "JUUL appears to be violating FDA regulations against making unapproved express and implied claims that its product helps users stop smoking cigarettes and is safer than cigarettes."
At the subcommittee hearing in July, several people testified that the company was directly marketing to children in high school, to the Cheyenne River Sioux Tribe and to smoking cessation groups.
In the letter, Krishnamoorthi pointed out testimony from Juul's CEO that said the product holds promise to "do what no previous technology has done -- help adult smokers stop smoking combustible cigarettes on a widespread and consistent basis."
The FDA said that it will respond to Krishnamoorthi about the questions raised in his letter and that the investigation is ongoing.
"In general, while the public may understand the term 'smoking cessation' as referring to ending the use of traditional cigarettes and switching to a non-combustible tobacco product, to date, the FDA has not approved any e-cigarette product as a smoking cessation aid under the safety and efficacy standard governing FDA-regulated medical products," FDA spokesperson Stephanie Caccomo said in an emailed statement.
"The FDA continues to closely scrutinize potentially false, misleading or unsubstantiated claims on a case-by-case basis to ensure that the public, including both adults and youth, are not misled."
Juul has maintained that its products are intended to convert adult smokers to what it described in the past as a less-harmful alternative. In other communications, the company says it cannot make claims that its products are safer, in line with FDA regulations.
"The JUUL system is designed to help adult smokers switch from combustible cigarettes to an alternative nicotine delivery system and is not intended to be used as a nicotine cessation product, or for the treatment of nicotine addiction or dependence," Juul Labs spokesperson Ted Kwong said in an emailed statement.
"Switching is not another word for cessation. They mean two very different things. Switching involves continuing to consume nicotine but from a different device, while cessation is about getting users to eliminate their nicotine consumption altogether. We are a switching product -- our product contains nicotine and is intended to switch adult smokers from one nicotine delivery system to another -- not a cessation product and that is clear in all of our marketing and communications," the spokesperson said.
The FDA revealed in November that vaping had increased nearly 80% among high schoolers and 50% among middle schoolers since a year earlier. Public health experts have said that Juul has largely propelled the rise, commanding about 75% of the e-cigarette market in the United States.
The FDA regulates aspects of e-cigarettes such as labeling, ingredients and marketing.
In a July post, acting FDA commissioner Dr. Ned Sharpless wrote that as an oncologist he is "all too familiar with the devastating impact of combustible cigarettes on the public health," and that many Americans have struggled to quit and "any product that can diminish the use of combustible cigarettes substantially has to be considered of enormous potential value."
However, he added that the answer is not clear if e-cigarettes are "that product" to help Americans quit.
Sharpless called e-cigarettes "one of the leading issues facing American public health," but added that the policies are still evolving in this area and that the devices remain a "top priority" for the agency.
Despite a general decline in smoking over the last decade, more than 16 million Americans live with some form of smoking-related disease according to the US Centers for Disease Control and Prevention. It remains the leading cause of preventable death. Smoking kills more than 480,000 people a year in the United States and an additional 41,000 people die after being exposed to secondhand smoke.