Authorities say two construction workers were injured when a girder fell onto equipment at a road construction site in Surprise.
Fire crews say one person fell 40 feet and was taken to a trauma center by helicopter. The second person's injuries are described as minor.
"He was on the pier cap to the east side of the girder and he was strapped to it and when that fell, he fell with it," said Doug Nintzel, ADOT spokesman.
The incident occurred Thursday morning near Bell Road and Grand Avenue where dozens of girders are being erected for elevated roadway.
According to the Arizona Department of Public Transportation, the contractor was adding 150-foot girders to an area crossing a railroad line.
Two cranes were lifting the girders into place when one fell.
Crews had to stop trains from coming through. The tracks opened back up at about 3:30 p.m.
ADOT officials say the injured are employees of the contractor.
"Our thoughts are with that family, that's our number one concern right now," said Nintzel.
The agency and the Arizona Division of Occupational Safety and Health are investigating the scene.