Summary: The NTSB found that a loose wire connection on the cargo ship Dali caused circuit breakers to trip, producing two blackouts that left the ship without propulsion and steering. The unmanned vessel struck Baltimore’s Francis Scott Key Bridge on March 26, 2024, causing a partial collapse that killed six construction workers; one worker survived with serious injuries and one crew member had minor injuries. Investigators pointed to wire-label banding, a fuel-pressure failure after a flushing pump stopped, the bridge’s vulnerability to larger vessels, and gaps in inspection practices as contributing factors. The NTSB’s final report is expected in several weeks.
NTSB: Loose Wire on Cargo Ship Triggered Blackouts That Led to Baltimore’s Key Bridge Collapse
Summary: The NTSB found that a loose wire connection on the cargo ship Dali caused circuit breakers to trip, producing two blackouts that left the ship without propulsion and steering. The unmanned vessel struck Baltimore’s Francis Scott Key Bridge on March 26, 2024, causing a partial collapse that killed six construction workers; one worker survived with serious injuries and one crew member had minor injuries. Investigators pointed to wire-label banding, a fuel-pressure failure after a flushing pump stopped, the bridge’s vulnerability to larger vessels, and gaps in inspection practices as contributing factors. The NTSB’s final report is expected in several weeks.
07:07 AM, 11/19/2025Society
Federal investigators say a single faulty electrical connection aboard the cargo ship Dali set off a chain of events that left the vessel without propulsion and steering and caused it to strike Baltimore’s Francis Scott Key Bridge on March 26, 2024, collapsing a section of the span and killing six construction workers.
At a public National Transportation Safety Board (NTSB) meeting in Washington, D.C., on Nov. 18, officials presented their probable cause findings. Investigators concluded that a loose wire in the ship’s electrical system caused a circuit breaker to trip unexpectedly, which initiated two separate blackouts at a critical moment as the ship approached the bridge.
What the investigation found
The NTSB determined the defective connection resulted from wire-label banding that prevented the conductor from being fully seated in a terminal block spring-clamp gate, producing an inadequate electrical contact. Investigators said the label likely was misplaced during the ship’s construction.
Crews restored power after the first blackout in roughly one minute, but a second outage followed when a flushing pump — which supplies fuel to the ship’s generators — stopped running, causing a drop in fuel pressure and requiring a manual restart. With propulsion and steering lost so close to the bridge, the pilots’ and bridge team’s attempts to alter the vessel’s course were ineffective.
Consequences and contributing factors
The collision caused part of the Francis Scott Key Bridge to collapse. Six construction workers on the span were killed; one worker survived with serious injuries, and one crew member from the Dali sustained minor injuries.
The NTSB also cited broader contributing factors: the bridge’s vulnerability to catastrophic failure from vessel impact, the increasing size of ocean-going ships since the bridge opened in 1977, and the absence of countermeasures that could have reduced the risk of collapse. Investigators noted the difficulty of locating a single defective wire among thousands on a nearly 1,000‑foot vessel — an effort likened during the hearing to finding a loose bolt in the Eiffel Tower.
Investigators highlighted gaps in maintenance and inspection practices: the ship’s crew performed periodic wiring checks but had no guidelines for inspecting individual terminal connections, and the vessel was not required to use infrared thermal imaging that might have detected the failing connection.
NTSB Chair Jennifer Homendy said the tragedy was preventable and extended the agency’s deepest sympathies to the families and survivors. She urged that lessons from this investigation be applied to prevent similar losses in the future.
The NTSB said its complete final report on the March 26 incident will be released in several weeks.