An airport’s operations were halted for several hours after officials discovered what appeared to be a bomb inside a human skull, inside a passenger’s checked bag.

Checked baggage screening was paused for two hours at Salt Lake City International Airport on September 18, after Transportation Security Administration (TSA) officers identified the unusual object at the baggage x-ray point.

According to TSA, officers saw a skull-like image on the X-ray with “unidentifiable components inside”. Since there was a chance it could be “an improvised explosive device”, they paused bag screening for two hours and contacted the Salt Lake City Police Airport Division.

The police’s explosives specialists were called to the airport, along with their bomb-sniffing dogs and the passenger of the bag was located and asked about the contents of their luggage.

The skull itself turned out to be plastic, while the bomb-like items inside were a sensor, nine-volt battery and putty, which worked together to form a medical training model used to train neurosurgeons and spinal surgeons.

While the two-hour delay turned out to be for nothing, TSA Utah’s federal security director Matt Davis said it represented how they treat potential threats.

“This incident and subsequent response is an example of how TSA must take every potential security threat seriously while making sure that the transportation system is not put at risk,” he said.

“I was pleased at the professionalism of everyone involved who worked closely to fully resolve the matter, to ensure that security was not compromised and to resume operations as quickly as possible.”

The passenger was transporting the item to a trade show in Cancun, Mexico but TSA officials decided he could not take it with him. Instead, the passenger could collect it when he returned to the airport.

This is not the most surprising or potentially dangerous item TSA officers have seen on the baggage security scanners.

Officers previously have found terrifying 1.2-metre-long creatures, weapons concealed in raw chickens, and even a dog hidden in unusual places.

If passengers have a “highly unusual item that could be flagged as a potential security threat” TSA encourages them to contact TSA when they arrive at the airport, so the item can be pre-screened and prevent the shutdown of operations.