Key findings: The NTSB concluded that a single misinstalled signal wire caused an electrical blackout aboard the container ship Dali, which lost propulsion and struck the Francis Scott Key Bridge on March 26, 2024. Investigators faulted the Maryland Transportation Authority for not conducting a recommended vulnerability assessment and criticized the ship operator for unsafe practices that hindered power recovery. Rebuilding is now expected to run through 2030 and could cost up to $5.2 billion, more than double the original $1.9 billion estimate. The report describes a chain of preventable failures that led to the collapse.
One Loose Signal Wire Triggered Dali Blackout and the Francis Scott Key Bridge Collapse — Rebuild Could Cost $5.2B
Key findings: The NTSB concluded that a single misinstalled signal wire caused an electrical blackout aboard the container ship Dali, which lost propulsion and struck the Francis Scott Key Bridge on March 26, 2024. Investigators faulted the Maryland Transportation Authority for not conducting a recommended vulnerability assessment and criticized the ship operator for unsafe practices that hindered power recovery. Rebuilding is now expected to run through 2030 and could cost up to $5.2 billion, more than double the original $1.9 billion estimate. The report describes a chain of preventable failures that led to the collapse.
07:53 AM, 11/19/2025Economy
The National Transportation Safety Board (NTSB) concluded that a single misinstalled signal wire caused an electrical blackout aboard the container ship Dali, leaving the vessel without propulsion or steering and allowing it to strike a support pier of Baltimore’s Francis Scott Key Bridge on March 26, 2024. The impact caused multiple bridge spans to collapse into the Patapsco River.
What the NTSB found
In its final report, the NTSB determined the immediate cause of the contact was "a loss of electrical power blackout due to a loose signal wire connection to a terminal block stemming from the improper installation of wireless label banding." Investigators said the crew reacted promptly but had insufficient time to restore power given the ship’s proximity to the span and delays restarting systems.
The board also identified wider systemic failures: the Maryland Transportation Authority (MDTA) did not perform a vulnerability assessment recommended by the American Association of State Highway and Transportation Officials (AASHTO), and therefore did not implement countermeasures that might have reduced the bridge’s risk of collapse after an impact.
Ship operator and crew practices
Engineers who examined the Dali testified that the crew had been using a flushing pump in place of a service pump for the ship’s diesel generators — a practice the vessel’s operator, Synergy Marine Group, failed to detect or stop. That misuse reduced the ship’s ability to recover electrical power after the blackout. The NTSB also cited Synergy for allowing critical electrical systems to run in manual mode rather than automatic, which impeded recovery.
"Staff found that Synergy operational oversight was inadequate because it did not discontinue crew's ongoing use of the flushing pump as a service pump for the diesel generators aboard the Dali, and at least one other vessel," NTSB engineer Bart Barnum said.
Communication and emergency response
The report highlighted communication breakdowns that prevented timely warnings to highway workers on the bridge, leaving them no opportunity to evacuate before the structure collapsed.
Costs and timeline for rebuilding
State officials now estimate reconstruction will extend to 2030 and could cost as much as $5.2 billion, more than double the original $1.9 billion projection used to secure federal funding. Jim Harkness, the MDTA’s chief engineer, attributed much of the increase to inflation and market conditions, and Transportation Secretary Sean Duffy had warned earlier that the final bill could be "double plus" the initial estimate once federal funds were committed.
Chain of preventable failures
The NTSB framed the disaster as a cascading series of preventable failures: from one improperly installed wire to years of unimplemented safety recommendations. Those factors combined to cause one of the deadliest infrastructure collapses in Maryland history and created lasting economic and logistical impacts across the region.
The NTSB report recommends stronger oversight of vessel maintenance and operations, more rigorous automatic systems testing, and that authorities complete vulnerability assessments for critical bridges and implement appropriate countermeasures to reduce collapse risk from ship impacts.