Transportation Security Administration agents have caught 4,495 firearms at security checkpoints so far this year, marking a 20-year record.

The discoveries are rare but up sharply, the agency said. So far in 2021, officers have found 11 guns in carry-on bags for every 1 million passengers screened, the TSA said. When the previous annual record of 4,432 guns was set in 2019, the rate was 5 firearms per million passengers screened.

It’s unclear whether passengers are more clueless or reckless, officials say, or precisely what is driving the increase. A decade ago, agents found 1,320 guns on passengers, according to TSA. Agency officials didn’t point to changes by officers themselves to the explain the increase.

“We believe that more people are carrying guns with them,” TSA spokeswoman Lisa Farbstein said. “The most common excuse is that they claim that they forgot that they had their gun with them.”

TSA Administrator David Pekoske called the number of nabbed guns alarming.

They “introduce an unnecessary risk at checkpoints, have no place in the passenger cabin of an airplane, and represent a very costly mistake for the passengers,” Pekoske said, pointing to escalating penalties for repeat offenders and loaded guns.

Agents caught guns at 248 airports, according to the TSA. The 10 airports with the highest tallies are as follows:

  • Hartsfield-Jackson Atlanta International Airport (391)
  • Dallas-Fort Worth International Airport (232)
  • George Bush Intercontinental Airport in Houston (168)
  • Phoenix Sky Harbor International Airport (147)
  • Nashville International Airport (115)
  • Denver International Airport (107)
  • Fort Lauderdale-Hollywood International Airport (107)
  • Salt Lake City International Airport (90)
  • Louis Armstrong New Orleans International Airport (90)
  • Dallas Love Field (88)