What we know about Baltimore's Francis Scott Key Bridge collapse

Just hours before the Tuesday morning commute was to get underway, the crew of a massive cargo ship leaving Baltimore harbor lost propulsion and control of the vessel, causing it to crash into a support column of Baltimore's Francis Scott Key Bridge, triggering a catastrophic collapse of the 1.6-mile long span and sending vehicles and people into the water, officials said.

The transportation disaster unfolded about 1:35 a.m., prompting a major emergency response from Baltimore police, firefighters and the U.S. Coast Guard as authorities estimated that up to 20 vehicles went into the water along with several workers who were part of a maintenance team fixing potholes on the span, officials said.

"I can tell you, our sonar has detected the presence of vehicles submerged in the water," Baltimore City Fire Chief James Wallace said at a news conference early Tuesday.

Maryland Department of Transportation Secretary Paul Wiedefeld said the depth of the water in the area where the crash occurred is about 50 feet.

Search and rescue efforts suspended

The Coast Guard said it would be suspending search and rescue efforts Tuesday evening and began recovery efforts Wednesday at 6 a.m.

Six workers who were part of the maintenance crew repairing the asphalt on the bridge remain unaccounted for and are presumed dead. Two of the missing construction workers were identified as Miguel Luna, who was originally from El Salvador and was a married father of three children, and Maynor Suazo Sandoval, an immigrant from Honduras, according to Court Appointed Special Advocates, a group that works with immigrants.

The group said Luna is a married father of three children, who has lived in Maryland for more than 19 years.

The Guatemala Ministry of Foreign Affairs said two of the workers who remain missing, ages 26 and 35, were originally from Guatemala.

Other workers who remain unaccounted for are believed to be from Mexico and Honduras.

"Based on the length of time that we've gone in the search, the extensive search efforts that we put into it, the water temperature -- at this point, we do not believe that we're going to find any of these individuals still alive," Rear Admiral Shannon Gilreath told reporters.

"We're hoping to put divers in the water and begin a more detailed search to do our very best to recover those six missing people," Col. Roland Butler with the Maryland State Police said.

'Abundance of twisted metal'

Imagery from underwater drones shows “an abundance of twisted metal and debris” from the collapsed Key Bridge, making it unsafe for divers to enter the water, according to a new assessment of the situation from the Department of Homeland Security obtained Wednesday by ABC News.

According to the report, "one truck and trailer" has been recovered from the water and a vehicle remains hanging from the metal structure of the collapsed bridge.

Investigators also determined there are 13 damaged containers aboard the cargo ship that are being inspected for any potentially hazardous materials.

“There is minor sheening on-scene. Booming has been ordered and is staged but will not be placed until search and rescue and dive operations are complete. The amount of potential oil spill is 1.8 [million] gallons of marine grade diesel,” according to the document.

During a White House press briefing Wednesday afternoon, Vice Adm. Peter Gautier, deputy commandant for operations for the U.S. Coast Guard, said the cargo ship was loaded with 4,700 containers, 56 of which contained hazardous materials.

"Most of these things are things like mineral oils and, even though they’re hazardous, we've determined that there really isn’t any kind of threat to the public," said Gautier, adding that the two containers that went into the water did not contain hazardous materials.

Gautier also said there was no sign that the container ship was leaking fuel or was taking on water.

At the same White House press briefing, U.S. Transportation Secretary Pete Buttigieg said that while there is no estimate yet on how much it will cost to rebuild the bridge, he said it "will not be quick, easy or cheap."

'We're with you,' Biden tells Baltimore residents

During a press conference Tuesday afternoon from the White House, President Joe Biden said he had authorized federal resources to be used in the search and rescue operation.

"We're incredibly grateful for the brave rescuers who immediately rushed to the scene. And to the people of Baltimore, we want to say, we're with you, we're going to stay with you for as long as it takes," said Biden.

The president echoed local, state and federal officials who said investigators have found no evidence linking the incident to terrorism. Biden called it a "terrible incident and accident."

Biden pledged that the federal government would pay to replace the bridge, which was built in the 1970s at the cost of $110 million, the equivalent of $500 million in 2024 accounting for inflation.

Maryland Gov. Wes Moore said at a news conference Tuesday morning that rescue crews are doing all they can to save lives.

"To the victims of this tragedy and their loved ones, all our hearts are broken," Moore said. "In the face of heartbreak, we come together, we embrace each other."

The FBI, which arrived at the scene an hour after the incident, confirmed that no link to terrorism was involved, according to Bill DelBagno, special agent in charge of the FBI's Baltimore field office.

Power issues reported before crash

Emergency officials said eight people were initially unaccounted for and two were rescued. The University of Maryland Medical Center said it treated one patient rescued from the bridge collapse and that person had been discharged from the hospital. The other person rescued was not injured, authorities said.

Two of the construction workers who were on the bridge and survived, including one who ran from the bridge and the other who fell into the water and swam ashore, according to the latest internal Department of Homeland Security briefing obtained by ABC News.

According to a Coast Guard memo obtained by ABC News, a harbor pilot and an assistant aboard the cargo ship reported the power issues that prompted multiple alarms on the bridge of the vessel and loss of propulsion. The pilots were operating the ship, not the ship's captain, according to Wiedefeld.

Biden said local authorities were alerted of the pending disaster and closed the bridge to traffic before the crash, "which undoubtedly saved lives."

Officials said the container ship was moving at a speed of 8 knots, or about 9 mph, when it struck the bridge. They said the disaster could have been much worse had authorities not stopped cars from going onto the bridge.

Moore described the crash as "unprecedented."

"To hear the words that the Key Bridge has collapsed, it's shocking and heartbreaking," Moore said.

All workers on the container ship were accounted for, according to the Coast Guard memo.

Moore said there were no structural issues with the bridge, saying it was "fully up to code."

It remains unclear what caused the loaded 984-foot container ship, Dali, a Singapore-flagged vessel, to crash into the bridge about a half hour after it began its intended journey out of the second-largest seaport in the Mid-Atlantic via the Patapsco River, under the four-lane Francis Scott Key Bridge, named after the amateur poet who wrote "The Star-Spangled Banner" in 1814.

The National Transportation Safety Board was sending a team to Baltimore to investigate the crash.

The White House said that after learning of the incident, Biden convened senior members of his team for a briefing on the bridge collapse. During the briefing, the president directed his team to ensure all federal resources be made available to assist in the ongoing search and rescue efforts, White House officials said.

Previous deficiencies found on cargo ship

Danish shipping company Maersk chartered the Dali cargo ship, a spokesperson for the company told ABC News in a statement.

"We are horrified by what has happened in Baltimore, and our thoughts are with all of those affected. We can confirm that the container vessel 'DALI', operated by charter vessel company Synergy Group, is time chartered by Maersk and is carrying Maersk customers' cargo. No Maersk crew and personnel were onboard the vessel. We are closely following the investigations conducted by authorities and Synergy, and we will do our utmost to keep our customers informed," the Maersk spokesperson said.

The Dali cargo ship had two deficiencies since it was built in 2015, according to records from the Electronic Quality Shipping Information System (Equasis).

The most recent deficiency was given on June 27, 2023, during an inspection in the port of San Antonio, Chile. The deficiency was for "propulsion and auxiliary machinery" concerning gauges and thermometers, according to Equasis. The other deficiency was given in 2016 for "structural conditions" concerning a damaged hull "impairing seaworthiness."

The records show that the last inspection of the container ship was on Sept. 13, 2023, in New York.

Dramatic security video captured the vessel striking one of the main support columns holding up the center cantilevered section of the bridge, causing the span to break apart in several sections and sending twisted metal into the water onto the bow of the Dali as black smoke began to pour from the vessel.

Multiple vehicles plunged from the bridge at the time of the collapse, the Baltimore City Fire Department said.

Just minutes before the crash, the video showed traffic flowing on the bridge, but the traffic almost disappeared before impact.

After reviewing traffic cameras, Maryland transportation officials confirmed "no vehicles [were] transiting the bridge at the time of the incident," according to the latest internal Department of Homeland Security briefing obtained by ABC News.

The pilot who was at the controls of the ship "is currently undergoing post-accident Drug and Alcohol Testing," the briefing said.

The Dali "remains impaled in the bridge," the document said, adding that several shipping containers with undisclosed cargo fell into the water. There is hull damage above the water line of the vessel, but the ship is maintaining watertight integrity," according to the document.

Had the crash occurred a few hours later at the height of the morning commute the bridge would have likely been packed with commuters. The bridge is part of the heavily traveled Interstate 695 linking Baltimore to Washington, D.C. An estimated 11.5 million vehicles cross the bridge annually, or about 30,000 per day, according to the Maryland Department of Transportation.

The bridge, which opened on March 23, 1977, had just celebrated its 47th anniversary.

The crash shut down the seaport, which serves more than 50 ocean carrier companies whose vessels make about 1,800 annual visits to the port, according to state officials.

ABC News' Victoria Arancio, Alex Grainger, Sam Sweeney and Felicia Alvarez contributed to this story.