A crude oil distillation unit at the Total-operated Lindsey Oil Refinery in North East Lincolnshire, UK, exploded killing a worker on Tuesday 29 June.
More than 50 firefighters were called to the facility to tackle the ensuing fire.
Employees at the refinery said the fire began in a superheated industrial heater near where they walked to work.
The fire has now been extinguished, and the sections of the refinery affected by the explosion have been shut down and safely isolated, Total says.
Formal investigations are being carried out by the police and the Health and Safety Executive.