A Pennsylvania man was arrested at Newark Liberty International Airport after he attempted to pass through security with a loaded 9mm handgun in his backpack.

Transportation Security Administration (TSA) officers, who have no authority to arrest people, spotted the handgun in the checkpoint X-ray machine at Terminal C and alerted Port Authority Police who confiscated the gun and interviewed the traveler, a resident of Canadensis, Pa., before arresting him on a state weapons charge.

In addition to being arrested, the individual also faces a stiff federal financial civil penalty for bringing a gun to a security checkpoint. The penalty for bringing a weapon to a TSA checkpoint can cost as much as $15,000, depending on the circumstances.

This was the 18th firearm detected so far this year at Newark Airport, the highest number at the airport in the past six years, according to the TSA.

Nationwide, TSA officers have prevented more than 4,000 guns from getting through security checkpoints so far this year.

Last year, 6,542 firearms were caught at 262 out of 430 airport security checkpoints nationwide. 88% of those guns were loaded.