A 27-year-old man has died after suffering serious burns in a major fire at an industrial unit in Alfreton.
Derbyshire Police said the victim, from South Normanton, died at the Queen's Medical Centre in Nottingham on Saturday.
Two other men were injured in the fire, but have since been discharged from hospital after treatment.
Around 50 firefighters were called to tackle the blaze at a vehicle repair centre off Lydford Road at about 12.10pm yesterday and local residents were advised to keep their windows and doors closed as a precaution.
A Derbyshire Constabulary spokesman said: "A joint investigation will begin today involving police, the fire service and the Health and Safety Executive."
At the height of the fire, nine fire appliances were at the scene, supported by a high-volume pumping unit.
The cause of the fire is not yet known. Anyone with information should call police on 101 or Crimestoppers on 0800 555 111.