The driver of the car, a 75-year-old man, is in a serious but stable condition after being airlifted to the University Hospital of Wales in Cardiff.
A woman who was the front passenger in the vehicle has sustained serious injuries and was taken to Nevill Hall Hospital in Abergavenny.
They were both taken to the Prince Charles Hospital in Merthyr Tydfil as a precaution.
A Welsh Ambulance Service spokesperson said a paramedic in a rapid response vehicle and three ambulances attended along with the Air Ambulance.
Gwent Police were also in attendance and the South Wales Fire and Rescue Service left the scene at 2.32pm.
THE one vehicle involved in this afternoon's crash left the road and collided with a stone wall on Mountain Road at around 1.37pm today.
A man and woman were already out of the car, which was carrying four passengers, when fire crews from Ebbw Vale and Tredegar arrived at the scene.
The other two passengers, a man and a woman, had to be freed by fire crews using hydraulic equipment.
Three casualties were taken to the hospital by ambulance and the other by air ambulance.
Fire crews left the scene at 2.32pm. The extent of their injuries in not known at this point.
THREE people have been taken to hospital by air ambulance following a crash on Mountain Road in Tredegar.
The three were freed by fire crews from their vehicle following the crash at around 1.37pm