The National Transportation Safety Board determined that a loose electrical connection on the containership Dali caused multiple power losses, leading the vessel to strike and collapse Baltimore’s Francis Scott Key Bridge on March 26, 2024, killing six highway workers.
The Singapore-flagged Dali, a 984-foot cargo ship, departed the Port of Baltimore shortly after midnight when it suffered blackouts due to improper wire-label banding installation that prevented secure terminal block connections. This resulted in loss of propulsion and steering as the ship approached the bridge. Despite crew efforts to restore power and drop anchor, the vessel’s bow struck Pier 17 at about 6.5 knots, causing the central truss span and adjacent sections to collapse onto the ship and into the Patapsco River.
A seven-person road maintenance crew from Brawner Builders and one inspector were performing pothole repairs on the bridge at the time. Six workers died, one survived with serious injuries, and the inspector escaped unharmed. One of the 23 crewmembers aboard the Dali sustained minor injuries. Vessel damage exceeded $18 million, with cargo losses undetermined.
Contributing factors included the Dali’s proximity to the bridge, limiting recovery time, and the bridge’s vulnerability to large vessel impacts. The Key Bridge, opened in 1977, lacked protective measures against modern ocean-going ships significantly larger than those considered in its design. A 1980 incident involving a smaller vessel caused only minor damage, highlighting size differences.
The NTSB noted inadequate pier protection and no motorist or worker warning systems. Although pilots issued a mayday call allowing traffic stoppage about 48 seconds before impact, construction workers received no direct evacuation alert, potentially leaving insufficient time to reach safe sections.
The bridge carried portions of Interstate 695, handling over 34,000 vehicles daily, including trucks with hazardous materials prohibited from Baltimore’s harbor tunnels. Its loss forced reroutes via I-95 and I-895 tunnels or the western I-695 loop, increasing congestion by at least 25 percent on some corridors and extending hazmat truck detours by up to 35 miles.
For Southern Maryland residents in Calvert, Charles, and St. Mary’s counties commuting north or accessing Baltimore-area routes, these detours added travel time via alternate paths like I-97 or Route 301 connections. Local trucking operations faced delays, particularly for goods moving through the port.
The NTSB issued over 20 recommendations, including urgent calls for bridge owners to assess vessel collision risks per American Association of State Highway and Transportation Officials guidelines. The Maryland Transportation Authority had not conducted such an assessment, which could have identified the bridge’s risk—nearly 30 times above thresholds—and prompted protections like enhanced dolphins or fenders.
Recommendations targeted federal agencies for interdisciplinary guidance on risk reduction, vessel redundancy for single-engine ships, improved voyage data recorders, and motorist warning technologies. Specific actions urged classification societies, manufacturers, and operators to address wiring practices, thermal imaging maintenance, and emergency generator configurations.
Rebuilding efforts progressed with pre-construction starting January 2025, including site surveys and test piles. Demolition of remaining structures began July 2025, expected to conclude within months. A progressive design-build contract awarded to Kiewit Infrastructure supports a cable-stayed replacement with higher clearance. Initial estimates ranged $1.7 billion to $1.9 billion for completion by late 2028, but November 2025 updates cited material cost increases, projecting $4.3 billion to $5.2 billion and opening delayed to late 2030. Federal funding covers the full amount.
The Port of Baltimore’s main channel reopened fully within 11 weeks of the incident, restoring most shipping. Ongoing work focuses on a design accommodating larger vessels while integrating safety features informed by the investigation.
The Francis Scott Key Bridge formed a key segment of the Baltimore Beltway, easing cross-harbor travel and supporting regional commerce. Its absence continues to affect daily commutes and logistics across Maryland, underscoring needs for resilient infrastructure over navigable waterways.
NTSB findings appear in Marine Investigation Report MIR-25-40.
