Other items that cause concern for TSA screeners are medically necessary devices, such as a back brace, which, in the wrong hands, could be used to hide an explosive.
Hawley said security personnel could likely detect bomb components with a pat down, but that they need to be prepared to deal with suspicious travelers who might use a brace to conceal explosives.
"Frequently, somebody will talk their way out of [it]: 'Oh, that's just I've got a sore back. Don't touch back there,'" Hawley said. "So officers have to be prepared for somebody doing a little bit of a fake or talking them out of it. And they just have to just maintain their distance and their discipline to determine whether or not there is a threat object."
"Officers have to be polite and professional, but they do have to take a look at it and they do have to resolve it."
A thin back brace Hawley showed ABC News hid high explosive RDX and a blasting cap, tucked away in the lining.
These items are part of a growing list of concerns for transportation security officials, who describe a fluid, ever-changing threat environment flush with increasingly creative terrorists.
"Its very sobering," Hawley said. "This is the real deal. They are taking harmless objects, even food objects and turning them into explosives. And we have to be prepared for that.
"You have to be switched on totally and realize that they're going to use everything they can get their hands on to use against us and they want us to kind of lull… we have to be skeptical, we have to look at it and see, does this represent an anomaly, perhaps a threat?"
Each time such an incident occurs, investigations to be launched to determine if it's simply a hoax, or a move by suspected terrorists to test the system to figure out what they can sneak on to a plane.
Hawley says he thinks the TSA's screeners are "the best in the world, and I think our guys have a very hard assignment," and that the agency constantly tests its ranks.
"We do those covert testing drills every day, every shift, every airport, and we use very, very sophisticated testing devices to keep them on their toes," he said. "And the challenge for training is to keep it fresh, not only do you have to know this stuff, but you have to keep alert for what we haven't briefed you on yet, you have to be alert to see if you're the first person to pick up a clue."
It's a daily game of cat and mouse, with thousands of lives on the line.