An overturned big-rig blocked all lanes of the westbound Gerald Desmond Bridge in Long Beach Tuesday afternoon.

It wasn’t immediately clear what caused the crash, but the truck and trailer ended up tipped over around 12:30 p.m., according to police and fire officials said.

Nobody was hurt, but the wreck snarled traffic coming off of the southbound 710 Freeway and going westbound on Ocean Boulevard in Long Beach, authorities said.

The truck also spilled a load of scrap metal onto the roadway, according to police.

It wasn’t clear how long the lanes would be shut down. Police said traffic on the 710 and Ocean Boulevard would likely be affected for the next few hours.