The Transportation Security Administration is using the $674,841.06 in cash passengers forget after emptying their pockets for airport security metal detectors during fiscal year 2014 for its own security operations.

Minneapolis-St. Paul Airport's cash collection is just a part of that — $6,896.81 in loose change was left behind at airport security in fiscal year 2014 — but has the 25th highest collection amount at any airport in the country, the TSA said.

The unclaimed money is documented and turned into the TSA financial office, but anything left unclaimed is used for the TSA's "critical aviation security programs," a March TSA report said. Congress authorized the TSA's spending of these funds in 2005.

This is MSP's highest collection rate in the past few years; the airport's TSA collected $5,772 in fiscal year 2013 and $4,983.31 in fiscal year 2012.

The TSA defines unclaimed money as "money passengers inadvertently leave behind at airport screening checkpoints during screening," it said in its report. Most times, these are coins they remove from their pockets to avoid aggravating metal detectors.

"TSA always seeks to ensure that all traveler property, including loose change, finds its way back to the proper owner," the report reads. "However, when loose change does not, it will be directed to critical aviation security programs."

The left-behind cash shouldn't be going to the TSA, said Douglas Kidd, the executive director of the National Association of Airline Passengers.

"The idea that TSA is using money that people have left behind to fund TSA operations is, to my mind, a real conflict of interest," Kidd said. "They should not be profiting from other people's misfortunes."

Wendy Thomson, co-founder of Freedom to Travel USA, called the TSA's decision to keep the loose change amounts "sleazy." She said that while losing a few cents probably won't impact the average passenger, the TSA could spend the money elsewhere.

"If they had an inkling of any type of goodness in them, they would at the very least donate it to a good cause," she said.

But donating funds to charity means extra money would be spent pinpointing where those donations would go, according to the TSA.

To eliminate instances of lost change at airport security, TSA spokesperson Lorie Dankers recommended that travelers put the change in a carry-on bag and secure it with a zipper.

"This will prevent the coins from being left behind in a bin and ultimately used to offset the cost for TSA operations," Dankers said. "TSA would prefer that travelers take their change when departing the security checkpoint."