Crashes involving more than 40 vehicles closed all lanes on the heavily-traveled U.S. 50 Bay Bridge in Maryland on Saturday, injuring 13 people and snarling traffic for about six hours, authorities said.

The Maryland Transportation Authority said on X, formerly Twitter, that the morning crashes on the westbound lanes closed the bridge and caused major delays for motorists.

The transportation authority said in a later post that eastbound and westbound traffic were alternating turns on the eastbound bridge, but the westbound bridge remained closed. Westbound lanes reopened Saturday afternoon, the transportation authority said on X.

Two people were taken to hospitals with serious injuries, authorities said. Eleven others also were hurt. None of the injuries were considered life threatening.

Twenty-three vehicles were involved in the initial chain-reaction crash and investigators believe about 20 others were involved in a series of secondary crashes, the transportation authority said.

Traffic cameras showed emergency vehicles with flashing lights and traffic not moving on the westbound lanes of the bridge. Several tow trucks removed vehicles involved in the crash from the bridge.

The cause of the crash was still being investigated Saturday afternoon, the transportation authority said.

The Anne Arundel County Police Department said motorists should anticipate heavy delays in Annapolis and Kent Island for an extended period of time.

Also known as the William Preston Lane Jr. Memorial Bridge, the span crosses the Chesapeake Bay. It connects Maryland’s Eastern Shore with the metropolitan areas of Baltimore, Annapolis and Washington, the transportation authority said on its website.

(AP)