At 9.44pm on Monday (31) one crew from Cottenham and one crew from Chatteris were called to a fire on Hill Row Causeway in Haddenham.
Firefighters arrived to find a fire involving farm machinery and extinguished it using a hose reel. One male casualty was treated for smoke inhalation at the scene.
The crews returned to their stations by 11.30pm.
The cause of the fire was deliberate. Anyone with information should contact police by visiting www.cambs.police.uk to submit an online report or call Crimestoppers on 0800 555111.