WASHINGTON (AP) _ Passengers on commercial airlines can now check in a can of Mace with their luggage, but face penalties if they carry the self-defense spray on board with them, the Federal Aviation Administration said Friday.

The agency adjusted its regulations in response to requests from flight crew and passengers who said they wanted a means of self-protection once they arrive at their destinations. Under the changed rules, passengers now can check in with their luggage one self-defense spray, weighing 4 ounces or less and containing not more than 2 percent tear gas.

Passengers bringing Mace or pepper spray on board the aircraft or not following the regulations face penalties of up to $25,000 and five years in prison.

``This added flexibility in the rules makes it completely unnecessary for passengers to bring these dangerous sprays into aircraft cabins where any release could hurt passengers and incapacitate flight crews, possibly endangering everyone on board,'' the agency said.

In October, a can of pepper spray went off on an America West flight, causing the pilot to deploy cabin oxygen masks during a landing.