Three people were killed and nine were hurt when a steel hangar under construction near the Boise, Idaho, airport collapsed Wednesday night, according to fire department officials.
Five of the nine injured are in critical condition, officials said.
One witness said the hanger caved in "like a house of cards."
"There was a catastrophic collapse of a metal structure at a construction site. First responders found a hectic scene and worked to secure and rescue victims," Division Chief of Operations Aaron Hummel said in a statement.
Hoists were needed to rescue some of the injured, and some of the rescues were "challenging," Hummel said at a press conference Wednesday night.
Everyone at the site was accounted for, Hummel said.
Jackson Jet Center said it was their 39,000 square-foot hanger that collapsed.
"Our hearts go out to everyone affected by this horrific event, especially those with loved ones on site when this tragedy occurred," the company said in a statement.
An airport official confirmed the building was on airport land but not a Boise Airport project. The airport itself was not impacted.
Representatives from the Occupational Safety and Health Administration are at the site and investigating.
ABC News' Marilyn Heck, Melissa Adan, Alyssa Pone and Matt Fuhrman contributed to this report.