Emergency services are at the scene of a serious collision involving a number of vehicles on the A30 westbound at Blisland.
The collision, involving a van, box van and lorry, happened on the single carriageway section shortly before the dual carriageway, shortly after 3.45pm today.
The road was closed as well as the on-slip to the A30 at Bodmin. The westbound carriageway has now reopened.
Collision investigators and scenes of crime officers are at the scene as well as the fire service.
The eastbound carriageway was closed at Carminnow and is expected to be closed for at least six hours while an investigation of the scene takes place.
Police say it will be closed until midnight at the earliest.
There are two casualties with serious injuries; one was airlifted to Derriford Hospital in Plymouth.
The collision involved a heavy goods vehicle and a box van.
Inspector Martin Taylor, based at Bodmin, said: “It will take time to clear the carriageway and recover the load from the HGV however we will get the road opened as soon as possible.
“I’d like to thank drivers for their patience and advise them to plan their journey this evening to avoid the area.”