GRABILL, Ind. (WOWO): Investigators say they likely won't be able to determine what exactly what caused a fire at the old mill in Grabill on Tuesday night.

According to our partners in news at 21Alive, the massive fire burned for over 12 hours.100 firefighters from 10 different departments were called in to put out the flames.

The mill was used to store lumber and the debris may take 2-3 days to clean-up.