The fire was found to have started accidentally.
The fire crews found an external diesel pump was involved in the blaze when they arrived at the incident in Askews Farm Road at around 8.20am today.
Firefighters poured foam over the fire to smother it.
They also worked with on-site staff to isolate the pump and remove as much excess diesel from the tank as possible.
The fire, which is believed to have started accidentally, was extinguished by 9am on the morning of Thursday, 21 January.
Fire crews ensured that the scene of the blaze was safe before leaving it in the care of the on-site staff at 10.30am.
For more on this story, and the latest on our other local and national news, listen to Time 107.5FM
Tags: Grays, Thurrock, Fire