A National Transportation Safety Board investigation determined that the containership Dali experienced a loss of electrical power, propulsion, and steering before striking the Francis Scott Key Bridge. The collision caused a substantial portion of the bridge to collapse into the river.
According to the NTSB, the blackout was caused by a loose signal wire connection to a terminal block. This issue stemmed from the improper installation of wire-label banding. The vessel's proximity to the bridge limited the crew's ability to recover propulsion following the loss of power.
The collision resulted in the deaths of six highway workers from a seven-person road maintenance crew. One worker survived with serious injuries, while an inspector escaped unharmed. One of the 23 people on board the Dali sustained a minor injury. Damage to the vessel exceeded $18 million.
The NTSB found that the bridge collapse was contributed to by a lack of countermeasures to reduce vulnerability to ocean-going vessel impacts. The agency noted that a vulnerability assessment could have been implemented if conducted by the Maryland Transportation Authority as recommended by the American Association of State Highway and Transportation Officials.
Additionally, the investigation identified a lack of effective and immediate communications to notify highway workers to evacuate the bridge as a contributing factor to the loss of life.
The bridge collapse has impacted regional transportation, forcing over 34,000 daily vehicles, including 10% trucks, to use alternate routes. These vehicles, which include those carrying hazardous materials prohibited from using local tunnels, must now take extended detours around the Port of Baltimore.
The NTSB issued several safety recommendations, including urgent directives to the Federal Highway Administration and the US Coast Guard to establish an interdisciplinary team to assist bridge owners in reducing collision risks. Other recommendations include researching hazard alert technologies and reviewing maintenance procedures for electrical components.
