Motorists have been warned of delays after the M4 was closed westbound near Port Talbot when a van crashed into a brick wall.
The collision happened at 1600 BST on Tuesday near junction 41.
The motorway was closed to allow the air ambulance to land and airlift one person to hospital.
The casualty was treated on a grass verge by a paramedic and a doctor. The eastbound carriageway re-opened but traffic was slow.
Mid and West Wales Fire and Rescue Service are making the scene safe.
One lane has now re-opened westbound.