The Route 715 visitors' gate at Aberdeen Proving Ground was closed for more than three hours Wednesday as security workers checked a vehicle suspected of having explosives in it, the Army said.
The gate is designated for visitors and commercial deliveries to the sprawling Harford County Army post. A delivery truck was being inspected around 9 a.m. when a military dog indicated it had detected potential explosive materials, according to a U.S. Army Garrison news release.
The truck was entering the post and going through a routine inspection when the dog alerted, according to garrison spokesperson Heather Roelker.
All other traffic was redirected to the post's Route 22 gate as security workers inspected the truck and questioned the driver and a passenger.
The Army garrison at APG notified the media shortly before 10:30 a.m that the Route 715 gate had been closed.
"Our security forces are taking precautions to close our Route 715 gate due to a suspicious vehicle attempting to gain entry to the installation," Roelker said at the time.
Operations at the post, which has about 18,000 to 20,000 soldiers and civilian employees, continued normally while the Route 715 gate remained closed. The Route 22 gate is typically open only to employees and contractors.
According to the Maryland State Fire Marshal's Office, bomb squad technicians conducted a thorough search of the commercial vehicle utilizing robotics.
"The vehicle was deemed safe and presented no hazard," the Fire Marshal's Office stated in a notice of investigation. "The scene was cleared without incident."
Post officials reported around 12:30 p.m. on social media that the incident had been resolved and that no one had been hurt.
The truck driver and passenger were "taken aside" to be questioned, but security officials did not detain them, APG's Roelker wrote in an email. The gate was reopened, and the truck and its occupants were allowed to continue onto the post once they cleared the full inspection, she said.
Tyler Grau, who works at APG, said there was a heavy security response to the incident.
"They seem to be taking it pretty seriously," he said. He described a SWAT-style truck and bomb squad vehicle near to the gate with several unmarked SUVs and more than a dozen cars and a tent set up further away.
The Harford County Sheriff's Office was assisting and had units on the scene, Sheriff's Office spokesperson Kyle Andersen said shortly after the incident was first reported. He referred additional questions to the Army.
Also assisting were the Aberdeen Fire Department and U.S. Army 55th EOD Unit, according to the Fire Marshal's Office.