More than 60,000 litres of used cooking oil caught alight during a storage barn fire in Hampshire.
The blaze was discovered just before dawn in Swanmore, near Southampton.
A Hampshire Fire and Rescue Service spokeswoman said firefighters could initially only contain the blaze as water could not be used on the oil.
About 40 firefighters and the Environment Agency were at the scene, which was being treated as a "serious hazardous materials incident".
A Hampshire Fire and Rescue Service spokeswoman said crews successfully extinguished the blaze and were damping down. The cause of the fire was not known.