SS Emidio was a 6912-ton tanker of the General Petroleum Corporation (later Mobil Oil), which became the first casualty of the Imperial Japanese Navy's submarine force action on California's Pacific Coast. Emidio was sailing in ballast from Seattle, Washington en route to San Pedro, California. The Japanese submarine I-17 found Emidio off Cape Mendocino on the early afternoon of 20 December 1941 and hit the tanker with five shells from its 14-cm deck gun.