Crews on Friday are continuing to assess the immense wreckage in the Patapsco River as specialized salvage equipment began to arrive following the collapse of a major Baltimore bridge earlier this week that killed six people and shut down a vital port, authorities said.

A 1,000-ton crane, the largest on the Eastern Seaboard, arrived near the collapse scene at 11 p.m., U.S. Coast Guard spokesperson Cynthia Oldham told USA TODAY. But before crews can begin removing the crumpled piles of steel and concrete, they must first survey the damage, a process that's been complicated by the river's strong current and low visibility, said U.S. Coast Guard Rear Admiral Shannon Gilreath.

“We’ve got to complete the assessment process of the bridge ... so we can figure out how to cut the bridge into the right size pieces so that we can actually them with the crane," Gilreath said at a news conference. "And we are doing those assessments right now."

The bodies of four construction workers who were on the Francis Scott Key Bridge when it collapsed are believed to be inside vehicles in the wreckage. Two people were rescued hours after the crash and on Wednesday two bodies were found inside a pickup truck submerged in the river.

Investigator recounts cargo ship's 'black box' audio

National Transportation Safety Board investigator Marcel Muise recounted audio discovered in the cargo ship's "black box" at a news conference on Wednesday, providing the most detailed account of the moments leading up to the catastrophic wreck.

• Muise said several alarms were heard on the recording just before 1:25 a.m., followed about a minute later by steering commands and rudder orders.
• At 1:26:39 a.m., the pilot on duty made a radio call for assistance to tug boats in the area, and 45 seconds later ordered the port anchor dropped.
• At 1:27:25 a.m., the pilot said on a radio call that Dali had lost power and was nearing the bridge. Around that same time, the officer on duty for the Maryland Transportation Authority told officers who were at both ends of the bridge for the road repairs to close traffic, which likely saved lives.
• At 1:29:33 a.m., as the powerless Dali was drifting at 8 mph, the VDR recorded "sounds consistent with the collision of the bridge," Muise said. Six seconds later, the pilot reported to the Coast Guard that the bridge was down.

– Minnah Arshad

14 containers with hazardous material 'impacted' by crash

Of the 56 total containers loaded on the vessel that contained hazardous materials, 14 were impacted by the crash, according to a statement from the Unified Command, which includes the U.S. Coast Guard and the Maryland Department of the Environment.

The statement said an industrial hygienist assessed the containers and found that those affected by the collision were soap products, perfume products, or not otherwise specified resin. First responders also observed a "sheen" around the ship, leading them to established a 6,000 feet yard safety zone as well as over 4,000 feet of containment boom to stop the sheen from spreading further in the river.

U.S. Coast Guard officials have said there is no immediate environmental threat and that response teams are conducting visual inspections of water quality and collecting samples for testing.

"Pollution and debris removal operations are on-going," a Unified Command statement published Thursday said. "At this time, no atmospheric hazards have been detected and the unified command continues to ensure safety."

Federal government provides $60M in funding for Baltimore bridge rebuild

The federal government is giving Maryland $60 million in emergency funds to rebuild the Francis Scott Key Bridge, Moore announced at a news conference Thursday. Moore said the state had submitted the funding request earlier Thursday for "initial mobilization, operations and debris recovery efforts."

The U.S. Department of Transportation’s Federal Highway Administration said in a news release that the request was approved within hours and the $60 million in “quick release” emergency relief funds will be immediately available for the Maryland Department of Transportation to rebuild the bridge.

The funds will be used as a down payment for initial costs, according to the Federal Highway Administration, and additional funding will be available as operations continue.

Federal Highway Administration administrator Shailen Bhatt said the emergency funding would go toward managing traffic and supply chain disruptions, removing debris, and ultimately rebuilding of the bridge.

While such funding can take days to approve, President Joe Biden had told reporters on Tuesday that he directed the federal government to "move heaven and earth" to quickly rebuild the bridge.

Experts have said the bridge could take years to rebuild and when it opened in 1977, it cost $60.3 million — which is equivalent to $316 million today.

Bridge collapse expected to have major economic impacts

The Port of Baltimore is a critical area for America's economy and is ranked as the largest vehicle-handling port in the country. The bridge's collapse on Tuesday immediately blocked shipping lanes and forced the indefinite closure of the port.

The economic impact of the bridge's collapse was estimated to be $2 million in wages a day and 8,000 jobs, according to Transportation Secretary Pete Buttigieg.

Between $100 million and $200 million of cargo passes through the port every day. About 4,000 commercial trucks use the bridge daily, and detours are expected to increase delivery times and fuel costs, according to Oxford Economics.

But with the port's closure, Buttigieg has warned that many longshore workers could be unemployed. Since the collapse, companies have rerouted shipments to other East Coast ports.

– Swapna Venugopal and Ramaswamy Paul Davidson

Contributing: Reuters