The commercial drone industry could be torpedoed if there were a serious accident involving a drone and a commercial aircraft, the chairman of the U.S. House Transportation and Infrastructure Committee warned on Friday.

Representative Peter DeFazio, a Democrat, said at a speech in Washington that regulators had to take the threat seriously.

“This is really serious when these things are flying around and it could kill the commercial drone industry,” DeFazio said, adding that if a toy drone “takes down a plane” there would be public outcry to ground the devices.

The issue of threats by drones to commercial air traffic came to the fore after London’s second busiest airport, Gatwick Airport, was severely disrupted in December when drones were sighted on three consecutive days.

Last month, 43 flights into New Jersey’s Newark Liberty International Airport were required to hold after drone sightings at a nearby airport, while nine flights were diverted.

In January, U.S. Transportation Secretary Elaine Chao proposed rules that would allow drones to operate over populated areas help speed their commercial use.

There are nearly 1.3 million registered drones in the United States and more than 116,000 registered drone operators. Officials say there are hundreds of thousands of additional drones that are not registered.

DeFazio added the government should also facilitate the growth of the drone industry, because the benefits are “potentially phenomenal.”

“We’re worried about the 2 million people who bought or got toy drones for Christmas the last couple of years who are regularly flying in violation of the law,” DeFazio said.

Last week, the FBI said authorities confiscated six drones that violated a temporary order not to fly the devices in the area ahead of the NFL’s Super Bowl.

Alphabet Inc and Amazon.com Inc are among a growing number of companies hoping to make package delivery by drones a reality.

The Federal Aviation Administration is also working on rules to set remote identification requirements for drones for tracking them.

The FAA noted last month that some drones can fly at 10,000 feet or more and accelerate from 0 to 60 miles per hour in less than one second and is assessing “possible performance limitations, such as airspeed and altitude, to mitigate potential hazards.”

Congress last year gave the Department of Justice and Department of Homeland Security new powers to disable or destroy threatening drones after officials raised concerns about the use of drones as potential weapons.

“We’re not certain yet what the best technology is,” DeFazio said. “We’ve got to get a handle on those who are operating improperly and then we also have to facilitate the growth of the (commercial drone) industry itself, because the benefits are potentially phenomenal.”