For five hours Tuesday, federal investigators discussed the four most momentous minutes in recent Baltimore history — the time between a massive container ship losing power and it when it struck and toppled the Francis Scott Key Bridge last year.

For families of the tragedy’s six victims, 89 seconds were especially weighty.

Upon receiving word from bay pilots aboard the Dali vessel, Maryland Transportation Authority Police quickly shut down traffic, surely saving the lives of drivers in the early morning hours of March 26, 2024. They did not, however, warn construction workers on the Key Bridge.

Doing so immediately could have given the crew a minute and a half to try to evacuate the doomed span.

“The highway workers may have had sufficient time to drive to a portion of the bridge that did not collapse,” said Scott Parent, a federal investigator.

That was among the findings revealed during a long-awaited meeting of the National Transportation Safety Board in Washington, D.C. The board, tasked with analyzing the disaster, presented maddening details about “preventable” ship blackouts that eventually caused the huge vessel to careen into a main bridge support.

A catastrophic sequence of events, starting with the loosening of a single wire among thousands, prompted the ship to lose the ability to steer. The board applauded the pilots and the crew members for their swift action in those fateful four minutes.

“For context, you now have been speaking longer than the Dali crew had time to respond,” NTSB engineer Bart Barnum said to a board member at one point, emphasizing the brief time frame.

They praised police, too, who were stationed at either side of the bridge to conduct traffic control during active construction, for stopping traffic.

MDTA police had the mobile phone number of an inspector on the bridge, an investigator said, but did not call to warn of the danger. Instead, one of the officers planned to drive to the worksite on the bridge after being relieved by another officer.

That inspector, Damon Davis, was located nearer to land and managed to jump to safety in time. He was present Tuesday in Washington, sitting near investigators.

“It was a terrible day for him,” having to relive the bridge collapse, said his attorney William H. “Billy” Murphy, who reminded reporters that litigation is ongoing.

The NTSB, an independent federal agency, investigates most major U.S. transportation disasters, including the 2023 derailment of a freight train and resulting chemical spill in East Palestine, Ohio, and the February midair collision outside Reagan National Airport. It issues findings of probable cause and makes general safety recommendations aimed at preventing similar events.

The safety board unanimously adopted investigators’ findings into the Dali’s power failures and bridge collapse Tuesday, issuing detailed safety recommendations to the companies that built, own and operate the Dali, as well as to the Coast Guard, MDTA and other regulatory bodies.

The hearing, which included questions from three members of the board, began with a moment-by-moment account of the disaster.

Investigators ruled out factors like environmental conditions, fuel quality, possible ship crew impairment and the bridge’s physical condition. They focused on electrical failures, mitigating steps crew members took to try to prevent the collapse, and urgent calls to law enforcement.

Faulty wiring resulted in a “precarious electrical connection” within the ship’s power system that led to the first of two blackouts as the ship left port.

Investigators found that infrared thermal imaging, a widely used technique in the shipping industry to inspect wire connections, was not in use on the Dali.

Asked afterward about the complexity of the investigation, NTSB Chair Jennifer Homendy pulled from her pocket a tiny part called a terminal block. A similar piece was an essential component of the wire that loosened.

“We are talking about a very small component here,” said board member Thomas Chapman. “And this is what caused all the problems, the poor connection within this terminal block is what started the sequence of events that resulted in the blackout.”

Investigators also noted the ship’s “inappropriate” use of a pump connected to a generator. Homendy criticized Synergy Marine Group, the ship’s operator, for not changing its policy concerning that pump in the 20 months since the collapse.

Tuesday’s hearing is not part of lawsuits filed in the wake of the collapse, including civil suits filed by the victims’ families against the companies that own and operate the ship. But the board’s findings could factor into how those lawsuits are resolved.

The Department of Justice last year accused Synergy and the Dali’s owner, Grace Ocean Private Ltd., of “jury-rigging” the container ship that felled the bridge. FBI agents boarded the ship as part of the federal investigation, and the DOJ could still bring a criminal case against the companies.

“[Today is] an incredibly difficult day for the family members to relive this event,” said Kevin Mahoney, a partner at the Kreindler and Kreindler law firm representing several victims’ families in a wrongful death lawsuit against the Dali.

He suggested that the ship could have blared its horn to warn workers on the bridge.

A trial to determine whether the Dali’s owner and operator were at fault is set for June 1 in federal court in Baltimore. Mahoney said the NTSB’s findings of probable cause and analysis are not admissible to the court, but the underlying facts brought up during the investigation are.

The Dali lost power twice while docked the day before departing the Port of Baltimore, but investigators said Tuesday that those failures did not materially impact the ship’s ability to disembark.

It then lost power twice after departing, causing it to veer off course, skirt past the bridge’s small concrete “dolphins” designed to nudge wayward ships back into the shipping channel, and careen into a bridge pier.

The NTSB continued to criticize the state of Maryland for not doing more to protect the bridge, noting that it was 30 times more susceptible to ship strikes than it should have been.

Had the authority conducted that assessment, said Parent, an NTSB investigator, “the MDTA would have had information to proactively identify strategies to reduce the risk of a collapse and loss of lives associated with the vessel collision of the bridge.”

In a statement, Synergy Marine and Grace Ocean said it would review “aspects of the vessel’s electrical arrangements,” while pointing to the vulnerability of the bridge. In turn, the transportation authority said it maintains that the bridge collapse “and the tragic loss of life were the sole fault of the Dali and the gross negligence of its owners and operators.”

Homendy said findings from Tuesday could ensure a similar accident “never, ever” happens again.

“The one silver lining,” said Mahoney, attorney for the families, “is that better understanding of this event might save lives in the future.”