The Food and Drug Administration conducted a surprise inspection at Juul Labs’ San Francisco headquarters last week, seizing “thousands of pages of documents” in relation to the e-cigarette company’s marketing practices, CNBC reports.

The FDA commissioner said earlier this month that teen use of e-cigarettes like Juul have reached an “epidemic proportion of growth,” and promised to take “historic action” action against the companies it believes markets to young people.

Juul has repeatedly said they do not encourage the use of their product by minors, with sales limited to those 21 and over. Still, with colorful flavors like fruit medley and creme brûlée, the nicotine vaping device has become immensely popular among teens, causing concerns about e-cigarette regulation.

Friday’s inspection “sought further documentation related to Juul’s sales and marketing practices, among other things,” the FDA said, according to CNBC.

The agency had demanded in September that more than a thousand retailers of e-cigarette devices provide plans within 60 days outlining how they will address “widespread youth access and use.”

Juul, projected to hit a $16 billion value this summer, is the largest producer of e-cigarettes, dominating 73% of the market, CNBC reports. According to Juul, the vaping device is “a true alternative” to cigarettes for adults.

“We are committed to preventing underage use, and we want to engage with FDA, lawmakers, public health advocates and others to keep JUUL out of the hands of young people,” said Kevin Burns, Juul Lab’s Chief Executive Officer, in a statement.

“The meetings last week with FDA gave us the opportunity to provide information about our business from our marketing practices to our industry-leading online age-verification protocols to our youth prevention efforts. It was a constructive and transparent dialogue,” the statement continued, adding that Juul looks forward to presenting its plan to prevent youth use within the 60-day time frame.

Burns also said that Juul has released over 50,000 pages of documents to the FDA since April supporting their public statements.