A fire at a Princeton business remains under investigation. Firefighters responded to an alarm at LCN Door Closures at around 3:45 yesterday afternoon. Upon arrival, they saw smoke outside the building. Once inside, they fought their way through heavy smoke and discovered the fire was in a furnace. It reportedly had been caused by a vat of super-heated oil. It took about five minutes to extinguish the blaze. Workers were evacuated during the fire, but no injuries were reported.