The WFM changed its name to the International Union of Mine, Mill, and Smelter Workers (more familiarly referred to as Mine Mill) in 1916. After a period of decline it revived in the early days of the New Deal and helped found the Congress of Industrial Organizations (CIO) in 1935. The Mine Mill union was expelled from the CIO in 1950 during the post-war red scare for refusing to shed its Communist leadership. After spending years fighting off efforts by the United Steelworkers of America (USWA) to raid its membership, Mine Mill and the Canadian Auto Workers merged in 1967 and were able to retain the name Mine Mill Local 598.