A loose electrical wire on the cargo ship Dali triggered a power outage that ultimately caused the collapse of Baltimore’s Francis Scott Key Bridge in March 2024, according to a report released by the National Transportation Safety Board. The board emphasized that the tragedy, which killed six construction workers, was preventable.
On the night of March 26, 2024, the Dali container ship lost propulsion and electrical power multiple times before crashing into one of the bridge’s support pillars. The impact caused the center span of the Francis Scott Key Bridge to collapse into the Patapsco River within seconds, sending vehicles and workers plunging into the icy waters. Six construction workers who were repairing potholes on the bridge fell to their deaths, while the ship’s crew survived. The incident severed a critical interstate highway and closed the Port of Baltimore, one of the busiest shipping hubs on the U.S. East Coast.
The NTSB’s year-long investigation, presented in a hearing on Tuesday, identified a single loose wire as the primary cause of the initial power failure. This wire, which was likely improperly connected during the ship’s construction a decade ago, tripped a breaker that supplied electricity to most of the ship’s equipment. NTSB officials demonstrated that the loose connection could replicate the blackout conditions, and Chairwoman Jennifer Homendy likened finding the fault to “discovering a loose bolt on the Eiffel Tower.” The crew attempted to address the issue but could not restore power in time to avoid the collision.
In addition to the loose wire, the NTSB cited other contributing factors, including problems with a fuel pump and a lack of redundant safety systems on the Dali. The ship experienced four power outages in the 12 hours leading up to the crash, but the final blackout occurred just minutes before impact, leaving the vessel adrift and unable to maneuver. Engineers noted that the electrical systems were improperly configured, making it difficult for the crew to recover from such failures. The board criticized the ship’s owners for inadequate maintenance and inspection procedures.
The NTSB also highlighted systemic issues beyond the ship itself. Investigators found that the Francis Scott Key Bridge had not undergone a vulnerability assessment, despite the increasing size of vessels using the Patapsco River. The risk of a collision was estimated to be 30 times higher than acceptable standards. Furthermore, police stationed at the bridge ends were notified of the ship’s deviation but failed to warn the construction workers, who might have had about 90 seconds to evacuate if alerted. NTSB engineer Scott Parent stated that this could have been sufficient time to reach a safe section of the bridge.
The collapse has had profound economic and social impacts. The Port of Baltimore was closed for months, disrupting supply chains and costing billions in trade. Initial repair estimates were around $1.9 billion with completion by 2028, but recent updates project costs up to $5 billion and a timeline extending to 2030. Maryland Governor Wes Moore attributed the increased expenses to rising material costs influenced by federal trade policies but reaffirmed the state’s commitment to rebuilding.
In response to the findings, the Maryland Transportation Authority maintained that the collapse was solely the fault of the Dali and its operators, citing gross negligence. The NTSB, however, emphasized that the accident was preventable and called for enhanced safety measures, including better wiring standards, regular electrical inspections, and improved bridge protection systems. The board’s recommendations aim to prevent similar tragedies in the future.
The release of the NTSB report marks a significant step in understanding the causes of the Key Bridge collapse and underscores the need for rigorous safety protocols in maritime and infrastructure management. As recovery efforts continue, the incident serves as a stark reminder of the vulnerabilities in critical transportation networks and the importance of proactive risk assessment.
