BOISE, Idaho (AP) — The names of three Idaho men killed when an airport hangar under construction in Boise collapsed were released by the Ada County Coroner on Friday.

Mariano Coc Och, 24 and Mario Sontay Tzi, 32, both of Nampa, were pronounced dead at the scene along with Craig Durrant, 59, of Boise.

Nine other people were hurt in the Wednesday evening collapse, including five who were taken to area hospitals with critical injuries, Fire Department Operations Chief Aaron Hummel said later that night. Officials have not released the names or the current condition of the injured victims.

The hangar is privately owned by Jackson Jet Center, a charter flight and maintenance company, and it was being built at the Boise Airport.

The collapse was reported about 5 p.m., and first responders had to stabilize the massive structure while trying to rescue those who were trapped inside and underneath it. Steel girders and panels were bent, and a large crane was folded in the wreckage.

The Ada County Coroner’s office was called to the scene a little over two hours later. All of the men died of traumatic blunt force injuries, according to a news release from the coroner’s office.

It’s not yet clear what caused the prefabricated steel building to collapse, and investigators with the federal Occupational Safety and Health Administration are working to determine exactly what happened. The investigation is expected to take several months.