Less than one hour after it left the Port of Baltimore, bound for Sri Lanka, the crew of the Dali sent a mayday signal, alerting port authorities that the ship had lost power and was out of control.
But it appears from videos that the vessel was travelling too fast and the crew were unable to avoid hitting the bridge.
The mayday call ensured that any additional cars were prevented from heading across the bridge, which Maryland Governor Wes Moore said “saved lives”.
Eight people who were working on the bridge deck repairing potholes fell into the Patapsco river. Two were rescued, six remain missing and are now feared dead.
Officials say the water temperature was about 48°F (9°C) at the time of the collapse. None of the 22-strong all-Indian crew were injured.
Shipping giant Maersk confirmed the ship was chartered by them and was carrying its customer’s cargo. It was being operated by charter vessel company Synergy Group.
The first emergency unit arrived on the scene at 01:50 ET (5:50 GMT). The ongoing multi-agency rescue operation is led by the fire department, collaborating with the US Coastguard and other Maryland agencies.
Governor Moore declared a state of emergency in Maryland at 10:00 local time.
US President Joe Biden gave a news conference later in the day calling the collapse “a terrible accident” and pledging to rebuild the bridge.