Fire crews rescued four construction workers Thursday after they became trapped in a flooded river tunnel.

Kevin Shirley, deputy fire chief for the Kansas City, Kan., Fire Department, said the four were treated for hypothermia and released.

"It turned out great," Shirley said. "The water wasn't terrifically cold but they had been in the water for some time."

Shirley said the men were working on a flood-control project, traveling by boat through a tunnel that links Turkey Creek with the Kansas River. Officials say workers routinely use the 90-year-old, 1,275-foot tunnel to travel between the two waterways.

Shirley said the boat capsized and two of the men were able to climb out on dry land about 800 to 1,000 feet into the tunnel, where they were found by rescuers. The other two, who were wearing life preservers, were swept downstream by the current.

Fire crews entered the tunnel in boats of their own and rescued the two men.

Shirley said the Fire Department had trained for such a rescue last summer.

"The thing is they knew this construction project was going to last for a while and they were concerned about somebody getting hurt," he said.