ST. LOUIS — Two people are seriously injured after a crash on northbound I-55 Tuesday. They have been taken to the hospital for treatment. It is not yet clear what caused the crash.

The crash closed the highway past Butler Hill Road at around 10:30 a.m. Many first responders are on scene. Traffic is backed up in the area.

This is a developing story. More details will be posted here as they come into the FOX 2 Newsroom.

Check FOX 2’s traffic map for real-time updates.