The National Transportation Safety Board (NTSB) revealed that a loose wire in the electrical system of the 984-foot Singapore-flagged containership Dali was the root cause of blackouts.
These blackouts led to the vessel striking Baltimore’s Francis Scott Key Bridge, causing a collapse that killed six highway workers and significantly disrupted port operations.
During a public briefing at its Washington headquarters, NTSB investigators explained that the loose wire prevented full insertion into a terminal block spring-clamp gate due to interference from wire-label banding.
This resulted in an inadequate connection that unexpectedly tripped a breaker, precipitating two power outages and subsequent loss of propulsion and steering on 26 March 2024, just as the ship neared the 2.37-mile-long Key Bridge.
Following the initial blackout, the Dali’s heading shifted sharply starboard toward Pier 17. Although pilots and the bridge team tried to steer the ship clear, the loss of power so close to the bridge rendered their attempts ineffective.
A major section of the bridge collapsed into the Patapsco River, with parts of the pier, deck, and truss falling onto the vessel’s forward containers.
READ: Audio reveals chaos before Dali hit Baltimore bridge
At the time, seven maintenance workers and one inspector were on the bridge; six workers died from the collapse. The NTSB found that swift actions by the Dali’s pilots, shoreside dispatchers, and authorities in Maryland to halt bridge traffic prevented more casualties.
Chairwoman Jennifer Homendy noted: “The Dali, at almost 1,000 feet, is as long as the Eiffel Tower is high, with miles of wiring and thousands of electrical connections.
“Finding this single wire was like hunting for a loose rivet on the Eiffel Tower. But like all of the accidents we investigate, this was preventable. Implementing NTSB recommendations in this investigation will prevent similar tragedies in the future.”
READ: Dali owners sue vessel builder over Baltimore bridge collapse
Investigators also highlighted the absence of measures to protect the Key Bridge from ship impacts. While a smaller vessel caused minor damage in 1980, the Dali was roughly ten times larger, exposing vulnerabilities in the bridge’s design dating back to its 1977 construction.
The NTSB subsequently issued safety recommendations to multiple stakeholders, including the US Coast Guard, Federal Highway Administration, standards bodies, shipbuilders, and manufacturers, to address risks and improve infrastructure resilience.
For more information:
National Transportation Safety Board – https://www.ntsb.gov/Pages/home.aspx
