The U.S. House Energy and Commerce has requested information from four major e-cigarette manufacturers: Juul Labs Inc., Fontem Ventures, Japan Tobacco Inc. and Reynolds American Inc.

House Energy and Commerce Chairman Frank Pallone (D-NJ) sent letters requesting data on marketing, research and sales, as well as whether advertisements and packaging allege that they are approved by the Food and Drug Administration (FDA) for use in quitting smoking.

Kaelan Hollon, a spokeswoman for Reynolds American, said the company is reviewing the letter and believes “minors should never use tobacco products, including vapor products,” according to Reuters.

Japan Tobacco said in a statement it welcomes any opportunity to “set out the responsible approaches” it takes in its marketing.

The requests come amid growing scrutiny of the e-cigarette industry by lawmakers.

Representative Frank Pallone, the Democratic chair of the committee, cited vaping-related lung illnesses recently reported by the Centers for Disease Control (CDC) and Prevention. He requested answers and documents by Sept. 20.