LAS VEGAS -- An accident at McCarran Airport in Las Vegas has left five construction workers injured.

It happened when a rebar cage collapsed at the Terminal 3 building site, on the northeast corner of the airport property, just off South Maryland Parkway and East Russell Road.

Workers were building a concrete pillar on the ground. Five men were inside when for some reason it collapsed.

Fortunately, they all survived -- largely because another worker went in and saved them.

“They really jump in, do whatever they can to help their co-workers,” Clark County Fire Department spokesman Scott Allison.

He kept a 30,000-pound rebar cage from crushing them.

"I don't know who the worker is but we've got to give him kudos. He literally got on the forklift, pulled over, got the forks within this structure and lifted the majority of the weight off these guys," Allison said.

The accident occurred at about 7 a.m. Tuesday at McCarran Airport's Terminal 3, which is currently under construction.

“Again, we do not know the reason for this rebar cage collapse. The cause is under investigation by the proper authorities,” said director of aviation, Randall Walker.

With the help of the fire department, all five workers were extricated and on their way to the hospital in about 30 minutes.

“The worst was a punctured lung and a fractured hip,” Walker said. “And that was the same gentleman. One patient has both of those injuries.”

Two men have already been released from the hospital, and the other three are in stable condition. Officials said it’s still a serious situation, but they know it could have been even worse.

“We're just really thankful all five of them are going to do well and be fine," said Walker said.

The men all worked for Pacific Coast Steel and that company has made more than 1,000 of these rebar cages for McCarran Airport alone.

Now, the Department of Aviation and OSHA are investigating and trying to figure out what was different in this case.

Construction did resume after the accident. Airport officials expect to open Terminal 3 in mid-2012.