Two women were taken to hospital following a serious road crash on the A1114 Baddow bypass at Great Baddow.
Police were called at 7.25am to a six-vehicle collision on the Chelmsford-bound carriageway just before the Great Baddow turn-off.
Two women were taken to Broomfield Hospital, Chelmsford, with serious injuries.
The northbound carriageway was closed. One lane northbound reopened shortly before 9am and the second lane is expected to be clear very shortly.
The southbound carriageway was closed for a short time while the air ambulance was in attendance.
Any witnesses who have not yet contacted police, or anyone with information about events leading to the collision, should contact PC Fiona Rayner at Chelmsford road policing office on 101.