Federal investigators say the Maryland Transportation Authority failed to complete a recommended vulnerability assessment that would have shown the Francis Scott Key Bridge was at significant risk of collapse from a ship strike long before its demise last year.

Sixty-eight bridges across the US should be assessed to see if they are at risk of collapse if hit by a ship, transportation safety officials found, while urging the bridges’ owners to undertake immediate vulnerability assessments.

The safety board issued recommendations as part of its ongoing investigation into the collapse of Baltimore’s Key Bridge last year after it was hit by a ship.