The lorry fire which has cloesd the A14 is expected to take all morning to clear.
The road is closed westbound between Alconbury and the Spittals Interchange, leading to traffic being diverted.
Fire crews are using machinery to remove straw bale from the lorry, break it down and stop it burning.
A Cambridgeshire Fire and Rescue Service spokesperson said: "It's likely to take all morning to clear. Traffic is being diverted but avoid the area if you can."