1 person trapped following crash involving big rig on 5 freeway in Boyle Heights

--UPDATE--

At 4:38 p.m., the California Highway Patrol declared all traffic lanes on the southbound 5 freeway near Fourth Street open.

EARLIER

A Thursday afternoon crash in Boyle Heights has left one person trapped inside the vehicle as firefighters rush to free that person.

The crash happened at about 3 p.m. on the southbound 5 freeway and Fourth street and it involved a semitrailer, according to the Los Angeles County Fire Department.

Multiple traffic lanes are blocked due to the wreck. Drivers are advised to take alternate routes and expect delays.

The cause of the crash is under investigation. No further details were immediately known.