A fog signal was installed in this building on November 30, 1895, to warn mariners of rock and reef along the treacherous Lake Superior coast when the tower light was less effective in fog. The building had 10-inch-thick walls filled with sawdust and covered inside and out with sheet metal, and it housed boilers, compressors, and other equipment needed to support the signal. Eighteen-inch whistles on the roof produced the signal with steam pressure, and in later years an air-driven diaphone foghorn produced a deep-throated warning that traveled for a long distance. A radio beacon transmitter was installed here in 1929 for use with the foghorn. The fog signal was decommissioned in 1978 and replaced by a bell buoy anchored near the entrance to Eagle Harbor. A loading dock and trestle walk to the building were built in a nearby cove in 1895 to receive deliveries brought over Lake Superior waters to the Eagle Harbor Light Station. The U.S. Lighthouse Service tenders Marigold, Amaranth, and Aspen carried supplies for this area, anchoring offshore while a scow transferred lamp oil, coal, and maintenance supplies to the dock.