The announcement ended a heavy security response that involved numerous agencies, including the FBI, the National Guard, and the Bureau of Alcohol, Tobacco, Firearms and Explosives. While the State Police bomb squad inspected the truck, officials closed a gate onto the base, shut down the exit from Route 2A to Hanscom, and evacuated several buildings.

“No one is under arrest. No one is suspected of a crime. What we’re trying to figure out is how some explosive material ended up on this package,” Major Fran Leahy of the Massachusetts State Police told reporters outside the base’s gate in Lincoln.

LINCOLN — Hanscom Air Force Base returned to normal Thursday afternoon after a moving truck that had tested positive for possible explosives was inspected and deemed safe. But some shipping crates in the truck contained a residue that will undergo further testing, officials said.


Television news helicopters circled overhead, relaying video of the scene, as troopers investigated the truck and its contents over several hours.

Leahy said the heavy security measures were appropriate in an era of heightened sensitivity to terrorist attacks.

“In looking back now on the response that was given, it was the right call by the United States Air Force and it was the right response,” Leahy said. “We realize it was an inconvenience to some of the people who work and live here but, given the times we live in, we operate in an abundance of caution.”

The incident began around 9 a.m., officials said, when a moving truck carrying belongings for a member of the military tested positive for explosives during a routine inspection at the base’s gate. State Police were summoned, and a dog from the bomb unit confirmed the presence of explosives.

That triggered a full response from state and federal law enforcement and security agencies.


Officials eventually determined that there were trace amounts of an explosive material on shipping crates inside the truck. Officials said they were not sure what the substance was, or where it came from.

The crates were sent to the State Police crime lab for testing, and the truck was deemed safe shortly after 1 p.m., and allowed to make its delivery, officials said.

Leahy said it was a “high priority of the Massachusetts State Police to determine what caused this event today.”

The truck belonged to Big Foot Moving & Storage of Acton.

“Big Foot Moving & Storage employees and company personnel complied with all request of state, federal and military authorities managing the inspection and investigation. Our vehicle and personnel have been cleared and we are thankful that the incident has been resolved,” Big Foot president and chief executive Mike Bavuso said in a statement.

“We thank all the authorities and military personnel for their thoroughness and their commitment to protecting our country every day,” he said.

The base oversees acquisition and implementation of Air Force technology, said spokesman Benjamin Newell.