A fire at a former factory site in Oxfordshire sent plumes of smoke towards neighbouring buildings.
Crews were called to Cherwell Business Park, Banbury, on Saturday at 0920 GMT.
The fire, caused by sparks from oxy-acetylene cutting equipment, ignited waste oil in a 10m-deep pit at the former biodiesel processing building.
A worker initially tried to extinguish which eventually took 30 firefighters to put out.
Specialist foam and support appliances were also called to tackle the fire.
The smoke from the oil sent thick smoke across nearby Southam Road and staff in neighbouring buildings were told to keep their windows closed.
No-one was hurt.