What we know about the recovery effort at the Francis Scott Key Bridge collapse site in Baltimore

BALTIMORE -- A search and rescue effort at the site of the Francis Scott Key Bridge collapse in Baltimore turned to a recovery effort Tuesday night, nearly 18 hours after the span fell into the Patapsco River. 

A bridge column was hit by a large container ship around 1:30 a.m., causing the bridge to crumble. 

Search and rescue turns to recovery

The U.S. Coast Guard announced Tuesday night that the all-day search and rescue effort for six missing people turned to a recovery effort, with those individuals now presumed dead.

Bodies of the victims had not been recovered as of Tuesday evening. All of the victims were construction workers who were filling potholes on the span at the time of the collapse.

Multiple agencies, including the FBI, sent dive teams into the water during the search effort. With darkness, those crews were pulled from the water as hope of finding the men alive faded.

Two more workers were rescued from the water shortly after the collapse.

Authorities said that a mayday had been issued from the ship shortly before the collision, which allowed them to stop stop traffic onto the bridge.

Sonar detected vehicles

Nighttime conditions hindered visibility in the early hours of the search, but crews using sonar detected vehicles in the river. 

It was not immediately clear how many vehicles fell into the water, but it is not believed that any passenger vehicles were driving across the bridge at the time. Construction workers did have vehicles parked nearby.     

The water below the bridge is 50 feet deep, Maryland Transportation Secretary Paul Wiedefeld said, and according to NOAA's National Data Buoy Center, the river water was 48 degrees overnight. 

Coast Guard leading mission at Baltimore bridge collapse site

The Coast Guard is leading the recovery mission at the Key Bridge site.

"We currently have three small boats," Lieutenant Commander Erin Palmer said early Tuesday. "We also have Coast Guard Cutter Mako, an 87-foot patrol boat. We have a helicopter from Air Station at Atlantic City. And we're working with numerous federal, state and local partners on scene on these search and rescue efforts."

Two people were recovered from the water shortly after the collapse. One was not hurt and one was taken to the hospital in "very serious" condition. The injured person was treated at the R. Adams Cowley Shock Trauma Center and later released.