While a decoy packed with fake explosives passes through the security line. Rea, the German Short hair Pointer, picks up the scent. 

She's one of more than 300 Passenger Screening Canines or PSCs at airports across the nation. Rea is working to sniff-out explosives at the Daniel K. Inouye International Airport.

As an extra boost to the Transportation Security Administration (TSA), these dogs train so nothing gets past their nose. 

"In order for us to be on our top performance level we have to train every day," Lance Nobriga, TSA K9 handler, said.

TSA says it can't disclose what the on-duty dogs have detected, but says role playing keeps their senses sharp.

Dogs like King, a white lab, has been detecting explosives for nearly seven years. He and Nobriga have been been pared-up for 5.

"He'll show me certain signs, animation is usually one of the key ingredients/components to his change of behavior," Nobriga said. 

Signs only a handler can read. Although the screening checkpoint is Kings typical patrol route, he and the other bomb-sniffing dogs have an all access airport pass. 

Nobriga says not all dogs can do the job...

"It takes a dog that has a strong will, a strong prey drive, so basically the reward is their prey. So they're paired to detect those orders and they know if they detect those orders they get their reward, which is their life basically," Nobriga said. 

But for those that can, they work hard.

"We do have that strong bond we have to have that strong bond in order to be efficient in our job and be capable of being the best we can be," Nobriga said.