The text of this article was updated 2/2/24 with new information.

The Ada County Coroner's Office identified the three workers who died in the Jan. 31 collapse of a pre-engineered steel hangar under construction at the Boise airfield as 59-year-old Craig Durrant of Boise, 32-year-old Mario Sontay Tzi of Nampa and 24-year-old Mariano Coc Och of Nampa. A probe into the incident is under way.

All three men died of traumatic blunt-force injuries. Nine other workers were injured during the collapse, which also involved a failed crane that was erecting the rigid steel frame. Five of the injured were hospitalized in critical condition, the Boise Fire Dept. said in a statement. Officials have shared no other details about the injuries.

Aaron Hummel, operations chief for the Boise Fire Dept., told reporters during a press conference workers were tying together the components of the when the collapse occurred at about 5 p.m. 

“The main structural members came down,” Hummel said. “It was fairly catastrophic.”

The U.S. Dept. of Labor’s Occupational Safety and Health Administration has started a probe into the incident and its investigators visited the site, a spokesperson says. Further information was not yet available.

Contractor Big D Builders Inc., Meridian, Idaho, is constructing the 39,000-sq-ft hangar, which is 45.5 ft tall, for Jackson Jet Center, a private plane charter and maintenance company, city permits show. Available records did not list a structural engineer.

Information about whether the workers were from Big D or a subcontractor was not immediately available. There were no union ironworkers on the job, according to Ironworkers Local 732 in Idaho.

Big D did not immediately respond to inquiries. According to the contractor’s website, it has 22 full-time employees, specializes in steel construction and has previously worked on at least one other hangar at Boise Airport. Big D Builders is not affiliated with Big-D Construction Corp., Salt Lake City.

Last year, OSHA fined Big D $21,875 for a fall protection repeat citation, records show. Officials said workers installing metal sheathing for a commercial building roof about 25 ft high were not using fall protection. OSHA had also issued a smaller penalty to Big D in 2022 after it found workers exposed to a 33-ft fall hazard while erecting steel on another project.