Heads up, air travelers: In the eyes of the U.S. Department of Transportation, Samsung Galaxy Note7 devices are no different from lighter fluid, anthrax, or radioactive uranium.

You can’t fly domestically with any of them—even if they’re in your checked bags.

This was the takeaway from a wacky weekend during which the DOT issued an emergency order declaring that the Android devices would be “considered a forbidden hazardous material under the Federal Hazardous Material Regulations” and banned them from all flights starting midday Saturday. 

The move came after repeated reports of the devices bursting into flames—a condition largely suspected to be the result of an issue with the battery. Samsung since has stopped making the devices and the company and the Consumer Product Safety Commission are pushing to reclaim every single Note7, including phones issued as replacements during the first wave of the recall.

If you do try to fly with one of the devices, the phone may be confiscated and you may face fines or criminal prosecution for evasion of a federal ban.

What’s more, according to a weekend report on NPR, airlines can deny boarding to people who don't give up their Note7s. If someone is spotted with the device on a plane, flight attendants for most airlines will ask the owner to turn it off and keep it “on their person” during the whole flight instead of in a seat pocket, or a bag, or an overhead bin. 

Still, other airlines are taking matters into their own hands.

Delta Airlines, Alaska Airlines, and Virgin America, for instance, last week invested in bright red fire-containment bags for some flights. The bags can withstand temperatures of 3,200 degrees Fahrenheit and were being rolled out gradually to each fleet, starting with transoceanic flights.

Other airlines were expected to follow suit on the fire containment bags; one report went so far as to suggest that soon these bags could be as prevalent on airplanes as seatbelts. International airlines gradually have banned Samsung Galaxy Note7 devices on their flights, too. Among the first: Air Berlin, Lufthansa, and Singapore Airlines.

Headlines from the recent ban brought back memories from last Christmas, when airlines banned hoverboards because they, too, were a consumer product with a tendency to explode mid-flight. Hoverboards, however, weren’t considered forbidden hazardous materials. Not even close.

Overall, in 2016 the FAA has reported 23 incidents of smoke, fire, explosion or extreme heat from lithium ion batteries or unknown types through September 7 in airplanes or airports—up from just 16 in all of 2015 and nine in 2014. Might the problem continue to worsen? Only time will tell.

Matt Villano is a freelance writer and editor based in Healdsburg, California. In nearly 20 years as a full-time freelancer, he has covered travel for publications including TIME, the Wall Street Journal, the New York Times, Sunset, Backpacker, Entrepreneur, and more. He contributes to the Expedia Viewfinder blog and writes a monthly food column for Islands magazine. Villano also serves on the board of the Family Travel Association and blogs about family travel at Wandering Pod. Learn more about him at Whalehead.com.