A single disconnection among miles of wires. A critical 89 seconds when those who died might have had a chance at safety. Risk analyses of dozens of other bridges.

On Tuesday, federal officials shed new light on what caused one of the largest disasters in Maryland history.

The National Transportation Safety Board held a meeting in Washington and issued a final report regarding the March 26, 2024, collapse of the Francis Scott Key Bridge that killed six construction workers.

Over roughly five hours, board members heard from a team of investigators and then peppered them with questions about what caused the 100,000-ton Dali container ship to lose power and veer off course, knocking down the structure that connected Dundalk and Hawkins Point over the Patapsco River.

Members confirmed many findings already made public — such as that the bridge, built in the 1970s, was inadequately protected from the threat of massive, modern vessels — but issued new findings as well as safety recommendations that will impact Maryland.

Here’s what we learned:

‘A needle in a haystack’

If not for a single wire, the Key Bridge might still be standing.

Investigators traced the first of two critical power failures the Dali experienced after departing the Port of Baltimore to a single faulty wire amidst thousands of electrical connections. The ship lost steering capability as a result of the ensuing blackout.

“I like to say it’s like a needle in a haystack. It is so hard to find,” said NTSB Board Chair Jennifer Homendy, who lauded investigators multiple times for meticulous work.

A simple label placed on the wire contributed to the malfunction.

The ship’s wiring was inspected three days earlier, but not by using infrared thermal imaging. That method would have been more likely to catch the problem than a manual inspection.

The board issued a slew of safety recommendations concerning that wire, including to HD Hyundai Heavy Industries, which built the Dali; to Synergy Marine, the vessel’s operator; and to WAGO Corp., the wire manufacturer.

Downplaying previous power failures

The Dali experienced two power failures the day before the collapse, while docked at the Seagirt Marine Terminal — the first caused by a crew member and the second because of a generator issue.

Department of Justice officials have said those power failures should have been reported to the Coast Guard, and alleged that the ship was not seaworthy.

But the NTSB downplayed the importance of the pre-departure power failures Tuesday, saying they did not “materially affect” the ship’s ability to leave the port.

The Dali twice lost power March 26, and its second power outage was caused by a problem with a pump connected to a generator. That was the same issue that caused one of the blackouts the day before.

Kevin Mahoney, a partner at the Kreindler and Kreindler law firm representing several of the families of the men who died in the collapse, said in an interview after the hearing that the second March 25 power failure amounted to a “dress rehearsal.” He disagreed with the board’s assessment to downplay the previous power failures.

“Our view is the Dali should never have departed,” Mahoney said.

A dozen bridges don’t meet risk threshold, including Bay Bridge

After the collapse, the NTSB urged bridge owners across the country to assess their structures’ vulnerability to future ship strikes and to take necessary measures to protect them.

Many of those bridges are still being assessed, and some have been found to meet modern standards for safety. More than a dozen, however, including both spans of the Chesapeake Bay Bridge, are over the acceptable risk threshold.

That threshold is one created for bridges built in the last few decades. But many bridges, including the Bay Bridge, predate those standards.

In an emailed statement, the MDTA said that the safety of Maryland highways and bridges is “always top priority,” and stressed that the Bay Bridge is inspected annually and is safe to drive on.

The state is in the midst of an estimated $177 million process to modernize the bridge’s pier protection.

“MDTA has taken steps to enhance the Bay Bridge’s physical protections because, although vessels have increased in size, weight, and speed, maritime regulations have not kept pace with the changes,” the authority wrote.

Officials also are planning a longer-term replacement of both spans of the Bay Bridge that would include pier protections.

Last-gasp efforts were fruitless

When the Dali lost power, bay pilots lost the ability to steer, and the ship was left at the whims of the water.

Natural changes in water pressure at the intersection of the main shipping channel with the Curtis Bay channel caused the Dali to veer slightly.

Over four frantic minutes, pilots and crew members shouted for desperate measures to prevent the collapse. For example, they tried the bow thruster, a small propeller used to help a ship dock.

“It was not effective,” said Bridget Quinn, an NTSB investigator.

The pilots also repeatedly called for emergency use of the anchor, which was deployed only about 10 seconds before impact.

Asked by a reporter afterward whether a quicker release would have made a difference, investigators said it would not have.

Maryland pilots adopted new protocol

Expert, local pilots are tasked with guiding every ocean liner in and out of Maryland waters, and three weeks before the bridge collapse, that group changed its emergency protocol.

Starting in early March 2024, if a ship posed a danger to a bridge, the pilot was supposed to call the Coast Guard.

The prior guidance had been for the pilot to call a pilot dispatcher, who would then contact the Maryland Transportation Authority and the Coast Guard.

But the Dali’s pilots, whose names have not been disclosed by the Association of Maryland Pilots, followed the old protocol.

Thank goodness they did, the NTSB essentially said.

“The response was timely and effective,” Quinn said.

Pilots have since changed their policy back to the old one, investigators said.