What we know about the Baltimore bridge collapse

A cargo ship rammed into Baltimore’s Francis Scott Key Bridge, causing the span to collapse and presumably killing six construction workers. On Wednesday, a day after the early-morning crash, officials with the National Transportation Safety Board boarded the ship and planned to recover information from its electronics and paperwork while divers searched for the bodies of workers who were still missing.

Here’s what we know so far about the collapse:

The operators of the Dali cargo ship issued a mayday call moments before the crash early Tuesday saying the vessel had lost power. But the 985-foot-long (300-meter-long) ship still struck one of the 1.6-mile (2.6-kilometer) bridge’s supports at 8 knots, which is roughly 9 mph (15 kph). That caused the span to break and fall into the water within seconds.

Eight construction workers were filling potholes on the bridge when the crash happened. Two were rescued soon after the collapse. Divers recovered the bodies of two others and the other four are presumed dead. Jeffrey Pritzker, executive vice president of Brawner Builders, said they were working in the middle of the span when it collapsed.

The U.S. Coast Guard said Wednesday that the ship underwent “routine engine maintenance” in the port before it lost power.

An inspection of the Dali last June at a port in Chile identified a problem with the ship’s “propulsion and auxiliary machinery,” according to Equasis, a shipping information system. The deficiency involved gauges and thermometers, but the website’s online records didn’t elaborate.

A “standard examination” conducted by the U.S. Coast Guard in New York in September didn’t identify any deficiencies, according to the Equasis data.

Given the vessel’s massive weight, it struck the bridge support with significant force, said Roberto Leon, a Virginia Tech engineering professor. The post can resist the impact by bending, Leon said, but cannot absorb the energy brought by such a “humongous ship.”

Last June, federal inspectors rated the 47-year-old bridge in fair condition. But the structure did not appear to have pier protection to withstand the crash, experts said.

“If a bridge pier without adequate protection is hit