A tractor has caught fire while travelling along a country lane near Aylesbury.
Crews from three stations were called to Chapmans Lane, off Tram Hill, near Brill just before 4pm on Friday.
The tank was split, causing burning diesel to leak onto the road.
No one was injured in the fire.
Buckinghamshire County Council are arranging for the road to be repaired.
Firefighters used absorbent booms from the Environment Agency, which are already carried aboard the fire engine, to prevent pollution of a nearby stream.