According to Transportation Security Administration officials(TSA), one concourse and a security checkpoint were closed on Wednesday at he Indianapolis International Airport after  a federal security officer left his vest inside.

The vest containing inert training materials was mistakenly left by the officer after overnight training, a TSA statement read.

The package contained several imitation explosives as well as wires and a battery, according to a police report.

An unidentified passenger found the vest this morning at the security checkpoint for concourse D. The vest was left in a pile of gray plastic bins used to send personal belongings through an X-ray machine.

The passenger alerted TSA officials, who oversee the checkpoint. Airport police evacuated and closed the checkpoint and adjoining concourse from about 5:10 to 6:30 a.m. Police then set up a perimeter for passengers while bomb experts removed the vest. The airport’s other three concourses stayed open.

The police report stated the vest contained a battery, wires, a switch, and a plastic bag containing a modeling-clay-like substance meant to resemble Semtex, a plastic explosive sometimes used in terrorist attacks.

The materials also included a second bag containing a small amount of liquid and a powder-filled tube, according to the report. The bag was marked with a label from a law enforcement training center in Stamford, N.Y.

The elements could not have been combined to create an explosive device, Airport Police Major Tom Hanna said. The incident still is under investigation by TSA and airport police.

Several East Coast-bound flights for United Airlines and U.S. Airways were delayed as a result of the closure, airport spokeswoman Susan Sullivan said. No flights were cancelled.

On Sept. 13, a pilot licensed to carry a handgun as part of the Federal Flight Deck Officer Program left his handgun at the Indianapolis Airport. The gun was found at the airport’s ground transportation center by a limousine driver.