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Crash killed construction workers in March 2024

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Maryland says bridge will now cost twice as much to build

and

take until 2030 to complete

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Board made series of recommendations to prevent future

incidents

(Updates with comments and background throughout)

By David Shepardson

WASHINGTON, Nov 18 (Reuters) -

The NTSB said on Tuesday a loose wire caused a power failure

on the 984-foot cargo ship Dali, leading to its March 2024

collision with Baltimore's Francis Scott Key Bridge that killed

six construction workers and destroyed the span.

The investigation found a single loose wire in the

electrical system caused a breaker to unexpectedly open,

launching a sequence of events that led to two vessel blackouts

and a loss of propulsion and steering.

The NTSB found wire-label banding prevented the wire

from being fully inserted, causing an inadequate connection.

NTSB Chair Jennifer Homendy compared the painstaking

search for the wire to finding a single loose rivet on the

Eiffel Tower. The NTSB and the ship's manufacturer HD Hyundai

Heavy had to test thousands of wires to find the

problem, she added. "It's like finding a needle in the

haystack."

The board also said contributing to the collapse was the

lack of countermeasures to reduce the bridge's vulnerability

from impacts by ocean-going vessels, which could have been

implemented if a vulnerability assessment had been conducted by

the Maryland Transportation Authority.

A replacement bridge was initially estimated to cost

$1.7 billion to $1.9 billion and be completed by late 2028. On

Monday, state officials said they now expect the bridge will

cost $4.3 billion to $5.2 billion and open to traffic only in

late 2030. They cited a new pier protection system and a new

longer, higher design as reasons for the increased costs.

The board staff said they recommended operators complete

periodic inspections of high-voltage switchboards and proposed

changes that would allow ships to more quickly recover from a

loss of power.

The NTSB has said previously the Dali lost electrical

power several times before the crash into the Key Bridge,

including experiencing a blackout during in-port maintenance and

shortly before the crash.

Power outages happen at sea and the NTSB made numerous new

recommendations to prevent catastrophic collisions, including to

the U.S. Coast Guard. It also called on Hyundai Heavy to

incorporate "proper wire-label banding installation methods."

The Key Bridge, like many other bridges, was not equipped

with a warning system to prevent motorists from driving onto the

bridge in the event of a hazard.

ASSESSING BRIDGE SAFETY

In March the board called for urgent safety assessments of

68 bridges in 19 states including crossings like the Golden Gate

Bridge, Chesapeake Bay Bridge, Brooklyn Bridge and George

Washington Bridge. The NTSB recommended major bridge owners

consider adopting motorist warning systems capable of activating

when a threat is identified to immediately stop motorists from

entering onto the bridge in an emergency.

The review focused on bridges built before 1991 and

frequented by ocean-going vessels that have not undergone

vulnerability assessments.

The NTSB said last year the Dali lost power about four

minutes before the crash when electrical breakers unexpectedly

tripped, causing a loss of power to all shipboard lighting and

most equipment when it was 0.6 mile (1 km) from the bridge.

The FBI is conducting a criminal probe into the collapse.

Homendy said some of the ship personnel are still in the

United States.