“Irresponsible construction methods” and a “blatant disregard” for safety led to the fatal collapse in January of an airplane hangar being built in Boise, Idaho, according to the U.S. Dept. of Labor Occupational Safety and Health Administration. The agency on July 26 cited the contractor, Big D Builders Inc., for one willful and three serious alleged violations of safety regulations and proposed it pay nearly $200,000 in fines.

Three workers were killed in the collapse, including Craig Durrant, a co-owner of the Meridian, Idaho-based contractor. Nine other workers were injured—eight seriously, according to OSHA.

OSHA inspectors found that Big D Builders was not using sufficient bracing or tensioned guy wires before the collapse. Officials also said the contractor continued work despite several signs the structure was unstable, including visibly bent I-beams, unbalanced columns and snapped wire rope cables.

Officials said steel erection work was performed in areas with mud and standing water that had not been properly graded and drained. Also, inspectors found pre-engineered rigid frames with bolts and heavy hex nuts that had not been tightened, and said employees were not given proper training. 

“The company’s irresponsible construction methods left the aircraft hangar’s structure extremely vulnerable,” said David Kearns, OSHA area director in Boise, in a statement. 

A representative for Big D Builders declined to comment on the citations due to a pending lawsuit filed by the families of two workers killed in the collapse. 

OSHA also cited Boise-based crane company Inland Crane Inc. over the collapse and proposed it pay a $10,000 fine. "OSHA recently informed Inland Crane that their investigation confirms our initial assessment that neither Inland Crane employees nor equipment were responsible for the hangar collapse," the company said in a statement.

Both companies have 15 days after receiving the citations to request a conference with OSHA or contest the findings.