NTSB Cites Loose Wire as Cause of Dali Key Bridge Collision

The National Transportation Safety Board determined Tuesday that a single loose wire in the electrical system of the containership Dali triggered blackouts that caused the ship to collide with Baltimore's Francis Scott Key Bridge on March 26, 2024, leading to the structure's collapse and the deaths of six highway workers.

The 984-foot vessel, en route from Baltimore to Singapore, experienced two power failures as it approached the 2.37-mile bridge spanning the Patapsco River. Investigators found that wire-label banding had prevented a critical signal wire from fully seating in its terminal block, resulting in an inadequate connection. This caused a breaker to open unexpectedly, cutting power to most of the ship's systems and eliminating propulsion and steering control. After the initial blackout, the Dali's heading shifted toward starboard, veering it toward Pier 17. The crew and pilots attempted to restore power and alter the trajectory, but the ship's proximity to the bridge, about 0.5 miles away, made recovery impossible. The impact at around 1:28 a.m. caused a substantial portion of the bridge, including pier, deck and truss spans, to collapse into the river onto the ship's bow.