Pockets of fire broke out at the coal store of Lafarge Cement Works in Dunbar at around 9.15am yesterday and firefighters spent around six hours dousing the fuel with water to prevent the blazes spreading.
It is understood the fire sparked through the natural drying-out process for the fuel, which was contained in a 30-metre-high industrial coal bin.
A spokeswoman for the cement firm explained that if stored for long periods and then moved, coal can start to heat.
She said: "We can confirm that the situation was fully under control at all times as the coal was methodically brought out and doused, and the fire service left site before 4pm after a discussion with the works operations manager.
"There was no disruption to the kiln during this time."