The Key Bridge Collapse and What the NTSB Found

Updated October 2026, after the NTSB's final findings. First published March 2024.

At about 1:29 a.m. on March 26, 2024, the containership Dali lost electrical power, propulsion, and steering in Baltimore and struck Pier 17 of the Francis Scott Key Bridge. A large part of the bridge fell into the river. A seven-person road maintenance crew and one inspector were on the bridge. The inspector escaped unharmed, and one worker survived with serious injuries. Six of the workers died.

The Baltimore Sun named them: José Mynor López, 37; Dorlian Castillo Cabrera, 26; Maynor Suazo Sandoval, 38; Alejandro Hernández Fuentes, 35; Carlos Daniel Hernandez, in his 20s; and Miguel Ángel Luna González, 49. They were originally from Guatemala, Honduras, Mexico, and El Salvador. They were working the overnight shift on the bridge deck when it fell.

We wrote about the collapse the day after it happened. That post speculated at length about markets, supply chains, and inflation, and most of it didn't hold up. This version keeps to what the National Transportation Safety Board found. The NTSB settled the probable cause at a board meeting on November 18, 2025: a blackout aboard the Dali caused by a loose signal wire connection to a terminal block. Two of its other findings apply well beyond bridges.

The Risk Nobody Had Calculated

The Key Bridge opened to traffic on March 23, 1977. Guidance from the American Association of State Highway and Transportation Officials (AASHTO) on assessing a bridge's vulnerability to ship strikes came out in 1991, and bridges built before then didn't have to be assessed. According to the NTSB's March 2025 interim report, the Maryland Transportation Authority (MDTA) "had not performed, nor was it required to perform," such an assessment, although AASHTO recommended it.

After the collapse, the NTSB ran the calculation itself. It put the bridge's annual frequency of collapse from a vessel collision at 0.002921. AASHTO's acceptable threshold for a critical bridge is 0.0001, so the bridge's risk was almost 30 times the threshold. Ships had grown in the decades since 1977, and the report points to the 2016 Panama Canal expansion as one reason larger vessels were calling at Baltimore. The NTSB found 68 other bridges whose risk was unknown for the same reason and wrote to their 30 owners.

A continuity plan has the same weakness. It describes the risks that existed when someone wrote it. For a broker-dealer, FINRA Rule 4370 requires an annual review "to determine whether any modifications are necessary in light of changes to the member's operations, structure, business, or location." That review is only as good as the questions it asks. A new vendor, a new office, a shift to remote work, or a move to T+1 changes what can go wrong, and the review should test the plan against each of those changes.

The Warning That Didn't Reach the Crew

The Dali's pilots, shoreside dispatchers, and the MDTA acted quickly to stop traffic onto the bridge, and the NTSB credited them with preventing a greater loss of life. The same warning didn't reach the people working on the bridge. The NTSB listed as a contributing factor "the lack of effective and immediate communications to notify the highway workers to evacuate the bridge."

That night, the warning worked by stopping cars. The crew already on the bridge had no equally fast way to hear it.

Every firm has people like that in its own plans: contractors, temporary staff, vendor employees working on site, visitors, staff at a client's office or on a late shift. Rule 4370 requires a plan to address "alternate communications between the member and its employees," and a call tree built from the employee list stops there. Check whether yours reaches everyone who would be in the building, or on your systems, when something goes wrong. Then test it by calling, at the hour when the fewest people are around to pass the message on.

Our post on continuity when staff can't reach the office covers the rest of what Rule 4370 asks of a broker-dealer.