EMERGENCY services were called to a crash involving seven vehicles on the A12, between junction 24 for Kelvedon and junction 25 for Marks Tey.
The smash on the Ipswich-bound stretch happened around 4.30pm today, Thursday July 24.
Essex County Fire and Rescue Service said no one was trapped but crews gave first aid to casualties and made sure the scene was safe.
A spokesman for the East of England Ambulance Service said three people were taken to Colchester General Hospital with minor injuries.
Other casualties were assessed by crews but did not go to hospital.
An Essex Police spokesman said: "Traffic is currently moving slowly past the scene of the collision and officers think they will not need to close the road."