Another construction worker has died at the CityCenter construction site. The Occupational Safety and Health Administration is investigating the death of a man.

Police said the man fell 50 to 60 feet into a trench Friday. He was wearing his harness at the time of the fall, police said, but they do not know if it was connected to the safety equipment. They also do not know if the fatality is weather related.

"We believe he was working on what would be called the Mezzanine Floor," Metro officer Scott Allison said. "He fell from there onto what would be considered the casino floor, right before the sub basement

The worker was between 40 to 45 years old, police said, but they would not confirm his identity.

About 4,200 workers were at the site at the time of the death.

Officials said this is the fourth death at the construction site since work began in 2006. Construction is scheduled to be completed in November 2009.