The Pacific Coast Marine Firemen, Oilers, Watertenders and Wipers Association (MFOW), commonly referred to as the Marine Firemen's Union, is an American labor union of mariners working aboard U.S. flag vessels. The Marine Firemen's Union is an affiliate union of the Seafarers International Union of North America AFL–CIO. The union was formed in San Francisco, California in October, 1883, by "firemen on coal-burning steamers."