BOSTON (AP) – State police are looking for a small batch of explosive material lost during a training exercise at Logan International Airport in Boston.

The Semtex explosive was attached to the bumper of a Massachusetts Port Authority truck Wednesday as part of a bomb-sniffing drill for police dogs, according to state police.

A Massport employee who was not involved in the training exercise, but who was authorized to be in the area, drove off in the truck, oblivious to the fact that there were about eight ounces of the material attached to the back, according to State Police Lt. Sharon Costine.

The employee drove about 1.5 miles, she said, before being stopped.

The explosive was missing from the truck.

“We’re really leaning toward the fact that it fell off the vehicle,” Costine said, “and possibly was swept up by a street sweeper.” Officials were searching the sweeper Thursday evening.

Costine said there is no danger that the material would explode without a detonating device.

“Running over it would do nothing,” she said, “you would need a blasting cap to set it off.”

The search for the explosive was confined to a nonresidential area along Harborside Drive near where the employee drove the truck.

As part of the investigation, Costine said, police have questioned the employee.