 I'm Peter McArthur, WDEL News. Fire investigators say the causes of a pair of commercial building fires in Newcastle County over the weekend were accidental. A fire at Tri-State Battery, Old Baltimore Pike Industrial Park Friday night caused by a malfunctioning lithium-ion battery. That blaze caused about 75 grand in damage. A fire in a building at the Delaware State Solid Waste Authority or the Delaware Solid Waste Authority on Lampson's Lane.