Police said the fire spread quickly after a loud detonation was heard early Saturday in the southern German town of Vohburg an der Donau. A huge smoke cloud could be seen miles away.
Residents were evacuated because of possibly toxic smokes. Air tests later showed it was safe for people to return to their homes.
The German news agency dpa reported all eight injured were Bayernoil refinery employees. It said some 400 fire fighters and police were on the ground to help extinguish the fire.
Authorities said the cause of the explosion was not known.