Detectives are treating an industrial estate fire involving three fuel tankers as suspicious, police said.
Emergency workers were called to the blaze at Lady Lane Industrial Estate in Hadleigh, Suffolk, at about 6.45pm last night.
Suffolk Constabulary said in a statement: "These inquiries are continuing but the fire is being treated as suspicious.
"Police have started inquiries to trace who started the blaze and are appealing for anyone with information to come forward."
Ten fire vehicles attended the "major incident" and firefighters worked throughout the evening to prevent the fire spreading across the site, Suffolk County Council said. Police confirmed the tankers contained 35,750 litres of kerosene, gas oil and diesel.