Law-enforcement officials in Oregon have moved to prevent sales of so-called “e-cigarettes” in the state, KTVZ-TV reported July 30.

In a move described as the first of its kind in the U.S., the Oregon Department of Justice went to court to block sales of the smokeless nicotine-delivery devices by two national truck-stop chains, Pilot Travel Centers and TA Operating, following an investigation by the agency. The settlement prohibits sales of e-cigarettes until the U.S. Food and Drug Administration (FDA) approves them or a court rules that the FDA lacks the authority to regulate the products.

“When products threaten the health and safety of Oregonians, we will take action,” said Oregon deputy attorney general Mary Williams. “If companies want to sell electronic cigarettes to consumers, they have to be able to prove they are safe.”

The FDA recently issued a warning against e-cigarettes, saying they contain carcinogens, and U.S. Customs has blocked some shipments of the products from entering the country. However, sale of e-cigarettes remains legal across the U.S.