SALT LAKE CITY (AP) — Salt Lake City International Airport has become a hot spot this year for gun-toting passengers.

In May, Transportation Security Administration screeners discovered a loaded gun strapped to a man's prosthetic leg. In July, they found two guns on the same day — both loaded. Earlier this week, they sniffed out yet another loaded gun in the carry-on bag of a man headed to Las Vegas.

The latest discovery brings the year-to-date total to 30. That is already significantly more than any of the previous three years — and more than double the number found this year in six airports with comparable volumes of passenger traffic such as Portland, St. Louis and Kansas City, TSA figures show. In Portland, for instance, only 13 guns have been found; eight in Kansas City.

The increase in Salt Lake City mirrors a national trend.

The number of guns found nationally by airport screeners has more than doubled in the past eight years — from 660 in 2005 to 1,556 in 2012.

This year is on pace to surpass that total again: the 1,150 guns discovered through August is a 20 percent increase over the same period last year.

TSA officials decline to speculate about the reasons behind the increase, but say the most common excuse from passengers is that they simply forgot they had a gun in their bag.

Passengers can travel with guns, but only when they declare them and put them in checked bags that are hard-sided with a lock.

Several of the people found with guns in Salt Lake City have been arrested on gun charges, but not all. That's the case around the country, too, where punishment depends on gun laws where the airport is located. If the state or jurisdiction where the airport is located has tolerant gun laws, police at the airport will frequently hand the gun back to the passenger and recommend locking it in a car or finding some other safe place for it. The government doesn't track what happens to the people who are arrested.

The TSA can also issue civil fines ranging from $200 up to $11,000 dollars, said TSA spokeswoman Lorie Dankers. In 2012, the agency issued $1.8 million in fines to passengers caught with guns.

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Airports in the South and the West, where the American gun culture is strongest, had the greatest number of guns intercepted last year, according to TSA data. Five of the 12 airports with the most guns were in Texas, and others included airports in Atlanta, Denver and Seattle.

The yearly totals can ebb and flow, too. In 2012, there were 33 guns found in the Austin-Bergstrom International Airport. This year so far, only 13 have been found.

At the Salt Lake City International Airport, where nearly 6 million passengers went through security checkpoints in 2012, guns aren't the only weapons uncovered. TSA officers stopped a passenger in January trying to bring samurai swords through the checkpoint.

In July, a grenade was found in a carry-on bag of a passenger headed to Denver, prompting this Tweet from Dankers, the TSA spokeswoman: "Friendly reminder 2 leave your grenades at home when traveling by air."