Bay Gateway was closed in both directions between Slyne Road and junction 34 of the M6 (Halton Interchange) at approximately 12.50pm today (August 4).
The fire service has since confirmed one vehicle was involved in the collision and three people have been rescued.
A spokesman for Lancashire Fire and Rescue Service said: "Two fire engines from Morecambe and Bolton-le-Sands attended.
"Three casualties were released from the vehicle and received first aid. Paramedics then administered trauma care.
"Firefighters used a medical kit, Holmatro equipment, road traffic collision equipment, and stabilisation equipment."
North West Ambulance Service said two air ambulances and three land ambulances were called to the scene.
"Three patients have gone to hospital," a spokesman added.
Motorists have been advised to seek alternative routes and avoid the area "to assist emergency vehicles attending".
"We will provide an update once the road is reopened," a spokesman for Lancashire Police said.
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