A man is being treated by paramedics after a crash between a 4x4 and a Luton van.
The crash happened on the B1023 at Inworth at around 4pm and the road is closed between Kelvedon Road and Oak Road.
The man, in his 50s, is conscious and breathing.
A spokesman for the East of England Ambulance Service said: "We have got an ambulance crew and an ambulance officer on the scene."
A spokesman for Essex County Fire and Rescue Service said it sent two crews from Witham to make the scene safe.
Update 5.20pm: The man has been taken to Colchester General Hospital suffering head injuries.
Two other patients were treated at the scene and discharged.
The man's injuries are not thought to be life-threatening.
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