Arsonists set fire to almost 200 tonnes of straw in Mepal in the early hours of Sunday morning.
Firefighters from Sutton and Ely were called at about 12.30am to a reports of a fire in Blackmoor Drive.
A stack of about 200 tonnes was alight and in danger of spreading to other stacks located nearby.
Crews from Papworth, Gamlingay were then called to assist with firefighting, and the high volume pump and hose layer were deployed to pump large quantities of water onto the fire.
At 5.40am the fire was extinguished and relief crews were called in to continue with dampening down, monitoring and checking the stack for hotspots.
Other crews who attended included Chatteris, Littleport, Ely, March and Manea.
Crews continued to return and monitor the incident on Monday.
The cause of the fire is believed to be deliberate. Anyone with information should contact the police on 101 or the independent charity Crimestoppers anonymously on 0800 555111.
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