The United Steelworkers (USW) is the largest international union in Canada and one of the largest unions of private-sector workers. It began in 1936 as the Steelworkers' Organizing Committee (SWOC), a creation of the fledgling Committee for Industrial Organizations (CIO) intended to sign up the thousands of unorganized workers in the American steel industry. SWOC soon persuaded previously independent unions of Canadian steelworkers in Sydney and Trenton, NS, and Hamilton and Sault Ste Marie, Ont, to join. Workers in a few other metalworking industries also formed SWOC locals. Some collective bargaining with 2 of the 3 primary steel companies began before WWII, but it took renewed organizing efforts during the war and a national steel strike in 1946 to consolidate the union's right to negotiate for the industry's workers in Canada. The union adopted the name United Steelworkers of America (USWA) in 1942. After the war it broadened its membership base to take in workers in many different industries.
In the 1960s the Steelworkers merged with the International Union of Mine, Mill and Smelter workers, the first of many partnerships that would see the union grow significantly in size and strength. From the 1970s to the 1990s, the union expanded to include unions in other industries, including upholstery, transportation communications and energy.
In the 1990s the diversity of membership increased when a number of unions merged with the USWA in Canada, including retail and wholesale, rubber and aluminum workers to become Canada's largest private sector union, now known as the United Steelworkers. Canadian members have their own national office in Toronto and one divisional and 3 district offices, for which they elect their own officers. The union has been a strong supporter of the NDP.
In 1984 a Canadian, Lynn WILLIAMS, was elected president of the international union. He retired in 1994. The second Canadian to hold the union's highest office was Leo W. Gerard, the union's seventh international president. He was appointed in February 2001 and elected by acclamation in November of that year.