A day after a preliminary report revealed new details about what happened in the collapse of the Francis Scott Key Bridge after a vessel strike, members of Congress peppered officials behind the federal response with questions about the ship’s power outage, the safety of other bridges and how to pay for a new bridge.

How might the ship’s power problems have been avoided? How prepared for massive ships was this bridge and how prepared are others across the country? How should the federal government recoup costs for a new bridge?

In the early morning of March 26, a huge container ship left the Port of Baltimore on a voyage to Sri Lanka, but didn’t make it very far. The 984-foot Dali lost power twice within about half a mile of the Key Bridge and it drifted into one of the bridge’s support piers around 1:30 a.m., collapsing the span and killing six construction workers.

A Coast Guard official said Wednesday that response officials in Baltimore believe the Dali will be refloated and removed from the middle of the waterway “early next week.” The Army Corps of Engineers hopes to reopen the federal channel by the end of May, if not sooner.

Meanwhile, other work remains ongoing. The National Transportation Safety Board, which released its preliminary report Tuesday, continues to investigate the cause of the vessel’s strike. The FBI has a criminal investigation. Transportation officials are planning for a new bridge.

The U.S. House Committee on Transportation and Infrastructure convened Wednesday’s hearing to explore the federal response. Here are five takeaways:

Dali’s power losses were distinct: About 10 hours before it left port, the Dali experienced a pair of blackouts, or complete losses of power, while the crew undertook engine maintenance, the NTSB’s preliminary report revealed.

The power losses in port, originally triggered by a mechanical problem caused by a crew member’s mistake, led the crew to switch the ship’s power supply to a different electrical transformer and circuit breakers, the report said. Those breakers tripped twice as the ship approached the bridge, rendering it mostly rudderless and without propulsion as it plowed into the support pier.

During her testimony, NTSB Chair Jennifer Homendy distinguished among the Dali’s four power outages.

“Preliminary information indicates that the March 25 blackouts were mechanically distinct from those that occurred on March 26,” Homendy told lawmakers. “Two were related to routine maintenance in port. Two were unexpected tripping of circuit breakers on the accident voyage.”

Figuring out what caused the breakers to trip as the Dali approached the bridge is at the center of what Homendy described as an investigation of “unprecedented” scale for her agency, which probes transportation disasters with the goal of preventing future tragedies, not holding anyone accountable.

“Switching breakers is not unusual but may have affected operations the very next day on the accident voyage,” Homendy testified. “So the configuration of the breakers remains under investigation.”

Coast Guard to assess major ports: The Key Bridge collapse spawned numerous questions about the safety of maritime operations around American ports and infrastructure.

Coast Guard Vice Adm. Peter Gautier said Wednesday that those questions warrant immediate attention, and that officials can’t wait until the conclusion of federal investigations into the disaster in Baltimore for answers.

“While we look forward to the results of these investigations, it is evident, looking more broadly, that the size and complexity of ships has grown over the years, placing greater demands on our marine transportation infrastructure that may not have kept pace with the increased risk that these vessels pose,” Gautier testified. “It’s time for us to more broadly understand these risks.”

Gautier told lawmakers he was convening a “nationwide Board of Inquiry” to evaluate the efficacy of the Coast Guard’s risk management resources and how they’re being put to use in major ports.

Describing the probe as a critical step to ensure “safe and secure flow of commerce on our waterways,” Gautier said it would “establish a holistic national level approach to develop risk profiles, identify ways to address vulnerabilities and propose actions to reduce the risk of major incidents.”

Homendy said she was “very encouraged” to hear the Coast Guard’s plan for a board of inquiry for ports across the country.

Questions over funding bridge reconstruction: President Joe Biden has pledged that the federal government would pay entirely to rebuild the bridge. But if Congress is fronting the cost of a new bridge, anticipated to approach a price tag of $2 billion, committee members asked Wednesday, how can it expect to get some money back?

Shailen Bhatt, administrator of the Federal Highway Administration, told lawmakers that under existing rules, any insurance funds recovered after an “emergency relief” event go back into the emergency relief fund. That program covers most of the costs of repairs to damaged roads and bridges following natural disasters and external catastrophic failures.

The roughly $1.7 billion to $1.9 billion emergency relief request related to the Key Bridge collapse is the second-largest ever received by the Federal Highway Administration, according to Bhatt. It is second to a $2.2 billion request made following Hurricane Katrina, he said Wednesday.

Bhatt also acknowledged, in response to lawmakers’ questions, that the Key Bridge had been redesignated following the collapse as part of the interstate highway system, rather than a state facility. That redesignation means it will be eligible for 90% or more of the costs to be covered by the federal program, rather than the 80% it would have qualified for without the designation.

Federal Highway Administration officials have told Maryland officials that they “believe” emergency relief funding will be available, which Bhatt said helps to relieve some “uncertainty.”

“I can pretty much with certainty guarantee this will not be 100% federally funded eventually, because we will recoup all of the insurance payments … and they will go back into the [emergency relief] funds,” Bhatt said. “But as the ranking member mentioned, we don’t want to wait through all of the litigation and the NTSB investigations, insurance issues, for that.”

Questions linger about pier protection: The NTSB’s preliminary report noted that the Key Bridge had four dolphins, or islandlike structures in the water, designed to protect its piers — two on each side of the bridge.

But those devices didn’t stop the drifting Dali from striking one of the bridge piers, which was surrounded by timber, concrete and steel. The surrounding protection remained relatively tight to the pier itself, Homendy said Wednesday, and the dolphins were “rather small.”

She said the NTSB has been comparing the Key Bridge with others that “have pier protection that comes out farther, so that a vessel can’t get to the column” and larger dolphins.

“In this situation, you have a bridge that began operations in 1977. If it was built today, it would be built differently,” Homendy said. “That has to be taken into consideration.”

She urged other bridge owners to conduct risk assessments of their own bridges with this in mind, alongside the growing size of container ships. It’s not necessary to wait until the NTSB investigation is complete to evaluate how protected a bridge is, she said.

“From a risk assessment standpoint, what is now going through? What is the vessel traffic? And how is our infrastructure protected?” Homendy suggested bridge owners ask.

Ancient law may get fresh look: Less than a week after the Dali crashed into the bridge, the Singaporean companies that own and manage the ship cited a pre-Civil War law enacted more than a century ago to limit or eliminate their liability in the disaster.

On April 1, Grace Ocean Private Ltd., the owner, and Synergy Marine Pte Ltd., which manages the 984-foot cargo ship, asked a federal judge in Maryland to clear them from liability or limit damages to the salvage value of the ship plus the revenue it stood to make from its cargo, which they estimated at $43.7 million.

To be successful, the companies have to prove they did nothing wrong. The city of Baltimore and a group of businesses argued in lawsuits they were negligent in allowing an allegedly unseaworthy vessel to sail.

No matter how the case plays out, one lawmaker said Wednesday, the law, designed to protect the maritime industry, needs to be reevaluated.

The Limitation of Liability Act of 1851 “really has to change,” said U.S. Rep. John Garamendi, a Democrat from California.

He told fellow lawmakers he intended to introduce legislation that would ensure “the owners of these vessels would be held responsible for the costs of their mistakes.”