A newly released report from the National Transportation Safety Board has identified a single loose signal wire as the trigger behind the catastrophic collapse of Baltimore’s Francis Scott Key Bridge. According to the NTSB, the misinstalled wire caused a total power failure aboard the cargo ship Dali just moments before it collided with a support pier on March 26, 2024.
Investigators said the problem stemmed from a label that had slipped too close to the end of the wire, preventing it from being fully seated in its terminal. With thousands of wires integrated into the ship’s systems, the small error led to a loss of propulsion and steering at the worst possible moment.
The report also faulted the Maryland Transportation Authority for not properly evaluating the bridge’s risk of being struck by large vessels, despite earlier safety recommendations. While the NTSB noted that the Dali’s crew reacted swiftly to the sudden blackout, the ship was already too close to the bridge to avoid the collision. “The crew’s actions were as timely as they could be—and impressive, given the situation,” said board member Michael Graham.
Additional criticism was directed at Synergy Marine Group, the ship’s operator, for insufficient oversight, including allowing the misuse of a flushing pump and keeping key electrical systems in manual mode rather than automatic. Communication breakdowns were also highlighted, as an overnight roadwork crew on the bridge did not receive warnings in time. Six workers fell to their deaths when the bridge collapsed.
The NTSB’s findings were released just a day after Maryland officials announced that rebuilding the bridge is now expected to cost up to $5.2 billion—more than double earlier estimates—and that completion will likely be pushed to 2030, two years later than previously planned.