Four fire crews dealt with an early morning barn fire which involved tyres and fertiliser as well as hay.
The blaze at a farm at Tal-y-Bont, Conwy, broke out at 0240 GMT, North Wales Fire and Rescue Service said.
The fire service said the building suffered heat and smoke damage and 90% of its contents were destroyed.
A joint police and fire investigation is under way but the cause of the blaze remains unknown. Crews from Llanrwst, Conwy and Colwyn Bay attended.
An environmental protection unit based at Holyhead was also called out.