Cowboys spokesman Brett Daniels said one worker was taken by a medical helicopter to a hospital and the other two were taken by ambulance. All three were conscious when they left the site, said Jack Hill, director of stadium construction for the team.
One worker was listed in critical condition at Baylor University Medical Center in Dallas, and the other two were in fair condition, a hospital spokeswoman said.
Fire and police officials did not immediately return calls seeking comment.
The more than $1 billion retractable-roof stadium is to open for the 2009 season and will be home to the 2011 Super Bowl. The 80,000-seat stadium is expected to be the world's largest column-free room, with retractable panels.
All three workers were wearing protective safety equipment at the time, Hill said. They all work for a subcontractor called Derr Steel Erection, which did not immediately return a phone message.
Construction did not halt, although an investigation is expected, Hill said. Shortly after the accident, crews in orange vests and hard hats were back at work throughout the sprawling site.
There are about 1,300 workers and about a dozen cranes at the site. The Cowboys have been working with the Occupational Safety and Health Administration and "we have a very good relationship with them," Hill said.
"We are very safety conscious, and this is a very unfortunate accident," Hill said. "We don't know the root cause and will certainly do an investigation and try to understand what happened."
There have been at least two other accidents at the stadium site that left workers hospitalized.
In August, a crane hook hit a worker in the back. He was sent to the hospital and released the next day. In January 2007, a stadium worker fell 20 feet through a hole between stadium levels. He was hospitalized in critical condition but recovered and later returned to work.
Arlington Mayor Robert Cluck said the project has a good safety record.
"Being a major project like this, with lots of moving parts, there's the risk of injuries, but I hate it when they do occur," Cluck said after arriving at the site.
The stadium, which has been under construction for two years, is on schedule for completion next June, Daniels said.
Thursday's accident came a day after a crane hook plummeted to the ground in Dallas and killed a worker after a cable snapped.
Workers there were examining part of an apparently damaged cable extending from a crane atop a several-story unfinished building at the time of that accident.
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