Fire fighters were called into action after two crashes on the same stretch of the A19 in a matter of minutes.
Crews from Stockton, Billingham and Hartlepool Fire Stations, joined police, the ambulance service and a Great North Air Ambulance helicopter, at the scene of two crashes involving five cars near Sheraton, at he turn off of the A179 to Hartlepool.
Fire fighters from Stockton Fire Station were assisting with the first collision - involving two cars on the southbound stretch of the road at 10am - when thee more vehicles crashed on the northbound part of the stretch about half an hour later.
Ian Bradley, Watch Manager at Stockton Fire Station, said: “We attended the first incident on the southbound carriageway when the second collision took place, on the northbound section.
“This turned out to be the more serious incident, with three vehicles involved and significant injuries to thre people, including a woman who was airlifted to hospital.
“We assisted at the scene for about two hours.”
One woman suffered critical injuries, requiring surgery and a blood transfusion at the roadside in the second collision.
Once she was stablised she was flown by the Great North Air Ambulance in a critical condition to the major trauma centre at James Cook Hospital in Middlesbrough in four minutes.
One person was arrested for dangerous driving.
Durham Police are appealing for witnesses to both crashes.