SALEM, Ore. -- The Oregon Department of Justice on Thursday banned the sale of "electronic cigarettes" at two travel store chains in Oregon.

Attorney General John Kroger's office said it was first ban of its kind in the country to prevent people from buying what it called "potentially dangerous products" that the U.S. Food and Drug Administration has yet to approve.

The devices are battery-powered and vaporize nicotine filters.

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"When products threaten the health and safety of Oregonians, we will take action," Deputy Attorney General Mary Williams said. "If companies want to sell electronic cigarettes to consumers, they have to be able to prove they are safe."

The A.G. said FDA tests showed a wide variation in the amount of nicotine delivered by three different samples of nicotine cartridges and the presence of nitrosamines - a known carcinogen.

The affected travel store chains, Pilot Travel Centers and TA Operating sell the "NJOY" brand at outlets in Oregon. The FDA had issued "Import Alerts" against NJOY and other brands of electronic cigarettes, and some had been detained by customs officials.

The settlement bans the sale of electronic cigarettes in Oregon until they are approved by FDA, or until a court rules the FDA does not have the authority to regulate the devices. The settlement says electronic cigarettes may not be sold in Oregon unless there is " competent and reliable scientific evidence to support the product's safety claims."