THE A13 was closed in both directions following a four car pile-up.
The crash happened at 10.25am on Friday on the Southend-bound track of the carriageway between Stanford-le-Hope and the Five Bells roundabout.
It involved two lorries, a Mercedes car and a Mercedes Van.
A 53-year-old man from South Ockendon was taken to hospital with serious injuries.
Firefighters had to use cutting gear to free him after he became trapped in the wreckage. The air ambulance was also called to the scene.
A 38-year-old man from Sheerness in Kent was arrested at the scene on suspicion of careless driving. He remains in custody.