(Updates with search details)
By Todd Melby
MINNEAPOLIS, Aug 2 (Reuters) - Divers searched for victims submerged in the swirling, murky waters of the Mississippi River on Thursday in what authorities said would be a slow and dangerous recovery operation after the worst U.S. bridge collapse in more than 20 years.
Working carefully in fast-flowing eddies created by crumpled steel and concrete, divers with only a foot (30 cm) of visibility had located some of the vehicles that were hurled into the river when the 40-year-old bridge gave way during Wednesday’s evening rush hour in Minneapolis.
“There are more than 10 vehicles in the river,” Fire Chief Jim Clack said, without indicating whether there were victims inside.
Four people were confirmed dead and authorities said the toll was certain to rise from the unexplained collapse of the 500-foot (150-meter) span.
“A bridge in America just shouldn’t fall down,” said Sen. Amy Klobuchar, a Minnesota Democrat.
More than 50 vehicles plunged 65 feet (20 meters) into the river and onto debris from Interstate 35W as the bridge collapsed in a plume of dust, smoke and screams.
More than 60 people were hurt, many suffering broken bones, head and spinal injuries.
Federal authorities quickly ruled out terrorism as a cause, but state and federal safety officials said the bridge’s inspection record did not indicate it was unsafe.
Specifically, the collapse raised questions about work being done to patch and resurface the bridge.
“What caused this unbelievable, almost incomprehensible tragedy?” added Republican Sen. Norm Coleman of Minnesota. “We need to understand that to make sure that this type of tragedy never happens ever again.”
The contractor on the project said state engineers were closely supervising the work that included pouring a fresh layer of concrete on the deck.
Mike McGray, owner of Progressive Contracting Co., said he had “no idea” what may have caused the bridge to give way. One of his workers was missing and presumed dead.
“People were pinned. People were partly crushed, talking to rescue workers ... telling them to tell their families goodbye” before they died, Minneapolis Police Chief Tim Dolan said.
“It is still a tremendously dangerous scene,” he said.
A Minnesota state senator, Satveer Chaudhry, said he drove over the bridge minutes before it collapsed and returned in his boat to help. He gave a ride to a volunteer rescuer who told Chaudhry “he saw (from a boat) stacks of cars submerged under water.”
Cory Swingen, 32, watched the disaster unfold from a tour boat. “I heard a loud rumbling sound, like a semi (trailer truck) running into a concrete wall ... the whole collapse took about 10 to 15 seconds,” he said.
When the dust cleared Swingen was relieved to see dazed people sitting or walking on the collapsed roadway.
People watched the recovery operation from grassy banks and the steps of the Guthrie Theater beside the river.
“These are horrible images but within each of those images is a story,” Minneapolis Mayor R.T. Rybak said. “That car you see tangled in the wreckage is someone’s cousin, brother or husband. ... Thank God this wasn’t worse.”
City officials said the search and subsequent clean-up would take several days. Searchers used sonar and engineers lowered the river level to aid the effort.
National Transportation Safety Board Chairman Mark Rosenker said investigators planned to rebuild the bridge piece by piece off-site to try to reconstruct what happened.
The bridge had passed inspections the past two years, Minnesota Gov. Tim Pawlenty said, though it was among thousands of bridges across the country deemed to be “structurally deficient” in a 2005 U.S. government report.
“(The rating) was by no means an indication that the bridge was not safe,” U.S. Transportation Secretary Mary Peters said.
She said it was the first time since 1983 that a bridge had collapsed without an outside trigger, such as an earthquake or collision. In that year, three people were killed in Connecticut in a bridge collapse on Interstate 95, the major U.S. East Coast highway.
The administration pledged $5 million for initial clean-up efforts in Minneapolis.
Additional reporting by Benno Groeneveld in Minneapolis, David Morgan and Doina Chiacu in Washington and Carey Gillam in Kansas City