Fire investigators say they may *never* know what sparked an industrial blaze in Fort Branch... The barn was rented out as a storage facility. When the fire broke out, the barn was filled with hay. Green hay has been known to combust, but investigators dont think that was the cause. They say the blaze began near a tractor that had been used earlier in the morning. Damage to the barn is so extensive, though, that is hard to say if the tractor is to blame.