Firefighters have been battling to stop a warehouse blaze spreading to 40,000 litres of industrial oil.
The fire was reported by a worker at the premises of an industrial cleaning supply firm in Stafford, Staffordshire, at about 8.43am on Wednesday.
More than 50 firefighters have been tackling the blaze at wholesaler Global Hygiene's office and warehouse site in Drummond Road.
Nearby businesses on the Astonfields Industrial Estate have been evacuated and residents told to keep their windows closed.
Photos and videos posted on social media showed flames shooting from the building's roof and a large, thick plume of black smoke rising over the town.
Staffordshire Fire and Rescue Service said one person was being treated for minor burns but there were no reports of any further casualties.
A fire brigade spokesman said there was "a large quantity of oil - a 40,000-litre container of heat transfer oil" on the premises, but it was not ablaze.
In total about 14 crews from both Staffordshire and the West Midlands Fire Service are attending the incident.
Emergency services have been using the nearby Stafford Rangers Football Club ground a few hundred yards away as a command post to organise the firefighting effort.
Rob Barber, Staffordshire Fire's director of response, said: "We are currently attending a large fire at Global Hygiene LLP on Astonfields Industrial Estate on Drummond Road in Stafford.
"Due to the significant amount of smoke that is billowing from the building, I would strongly advise residents to keep their windows and doors closed."
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