Juul illegally described his e-cigarette as "safer than smoking," according to the FDA

The federal health authorities on Monday criticized the vape giant Juul Labs Inc., accusing it of illegally manufacturing its electronic cigarettes as a safer alternative to tobacco, and ordered the company to cease to make unproven claims regarding his products.

The Food and Drug Administration has also increased its focus on a number of key aspects of Juul's activities, including asking for documents related to its marketing, educational programs and nicotine formula.

FDA action is increasing legal pressure on the country's best-selling vape company, which has been tightly controlled by state and federal authorities since the recent vaping of miners. Federal law prohibits sale to persons under 18 years of age. The FDA had been investigating Juul for months but had not taken any action against him.

A Juul spokesman said the San Francisco company was reviewing the FDA's comments and that it would "cooperate fully".

In a harsh warning letter, the FDA pointed to various claims by Juul's representatives, particularly that its products are "much safer than cigarettes". No vaping product has been tested by the federal government to be as harmful as traditional tobacco products.

Over the past year, Juul has been trying to position his e-cigarettes as a way to help adult smokers quit using the slogan "Make the switch." In a separate letter to the company, the FDA was "concerned" by the fact that its campaign suggests "that the use of Juul products presents less risk or is less harmful than smoking."

"Juul has ignored the law and, which is very disturbing, has made some of these statements at school to the youth of our country," said Acting FDA Commissioner Ned Sharpless in a statement.

The agency's warning letter highlights an incident reported by two high school students in New York during a congressional hearing in July. The students said that a representative of Juul had been invited to address the school as part of an assembly on mental health and addiction issues. During the presentation, the students stated that the company's product was "totally safe". He also showed students a Juul device and claimed that the FDA "was about to say that it was 99% safer than cigarettes".

Juul says he ended his school programs – which aimed to discourage the use of minors – last September.

Among young people, vaping flew to what US authorities have called epidemic levels. Bloomberg said that the consumption of electronic cigarettes among high school students had increased by 78% last year compared to 2017, reaching more than 3 million students.

FDA warning letters are not legally binding, but regulators can sue companies for failing to comply with government demands.

Electronic cigarettes have been on the US market for more than a decade, but the FDA has been given the power to regulate them only in 2016. Electronic cigarette manufacturers have until May to submit their products to the FDA for medical examinations.

Most experts agree that aerosols for electronic cigarettes are less harmful than cigarette smoke because they do not contain most carcinogenic byproducts of burning tobacco. But there is virtually no research on the long-term effects of vaping. Electronic cigarettes generally heat liquids containing nicotine.

In a letter to Juul CEO Kevin Burns, FDA regulators said they were "troubled" by a number of other points raised during the hearing before the Congress. The letter quotes congressional testimony that Juul's advertising was "saturated channels of social media frequented by underage teens" and "influencers used and coupons to attract new customers".

Last year, Juul closed its social media sites. And under pressure, he voluntarily removed his fruit and dessert aromas from retail stores.

Juul is a private company. Tobacco giant Altria Group Inc., whose brands include Marlboro and Parliament, acquired a 35% stake in Juul in December for close to $ 13 billion.