(Photo by Casey Kuhn - KJZZ)

A large concrete girder collapsed at the Bell Road and Grand Avenue construction site in Surprise.

Two construction workers were injured in Surprise this morning at the overpass work site on Grand Avenue. One of those men is in critical condition.

The worker was airlifted to a trauma center after suffering injuries from a 40-foot fall.

The 150-foot concrete girder had just been placed in construction above the railroad tracks next to Grand Avenue and Bell Road when it collapsed.

Arizona Department of Transportation spokesman Doug Nintzel said finding out why the girder fell will delay what was supposed to be a six- to eight-month construction project.

“We are going to have to take some time to investigate because safety and the investigation itself, those have to become our priority right now," Nintzel said.

Workers have been building the Arizona Department of Transportation overpass project since April.

Officials said the other man escaped with minor injuries.

ADOT is still investigating the cause of the collapse.