NNA - U.S. federal safety investigators recovered the black box from the freight ship that crashed into a Baltimore bridge, the agency chief said on Wednesday as rescuers searched for the remains of six construction workers lost in the bridge collapse.

A highway team also will be looking at the twisted remains of the Francis Scott Key bridge as they try to determine how and why a container ship smashed into a pillar of the 1.6-mile (2.6 km) span in early morning darkness on Tuesday.

Investigators from the U.S. National Transportation Safety Board recovered the data recorder after boarding the ship late on Tuesday, NTSB Chair Jennifer Homendy said. They will interview the ship's crew and other survivors, she said.

The disaster forced the indefinite closure of the Port of Baltimore, one of the busiest on the U.S. Eastern Seaboard, and created a traffic quagmire for Baltimore and the surrounding region.

Rescuers pulled two construction workers from the water alive on Tuesday. One was hospitalized. The six presumed to have perished included immigrants from Mexico, Guatemala and El Salvador, said the Mexican Consulate in Washington.

Officials said the eight were part of a work crew repairing potholes on the road surface when the Singapore-flagged container vessel Dali, leaving Baltimore bound for Sri Lanka, plowed into a support pylon.

A trestled section of the bridge almost immediately crumpled into the water, sending vehicles and workers into the river.

The U.S. Coast Guard said it was looking for the bodies 18 hours after they were thrown from the bridge into the frigid, 50-foot-deep waters at the mouth of the Patapsco River.

"They are down there in darkness where they can literally see about a foot in front of them, they are trying to navigate mangled metal" in a place where people are presumed to have lost their lives," Maryland Governor Wes Moore said at the scene.

Moore said at a Tuesday news briefing the bridge was up to code with no known structural issues.

The 948-foot (289-meter) ship had reported a loss of propulsion shortly before impact and dropped anchor to slow the vessel, giving transportation authorities time to halt traffic on the bridge before the crash. That move likely prevented a higher death toll, authorities said.

It was unclear whether authorities also tried to alert the work crew ahead of the impact.--Reuters

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