The 46,000 members of the Aluminum Workers of America voted to merge with the budding steelworker union that was the USW in June 1944. Eventually, eight more unions joined the USW as well: the International Union of Mine, Mill and Smelter Workers (1967); the United Stone and Allied Product Workers of America (1971); District 50, the Allied and Technical Workers of America (1972); the Upholsterers International Union of North America (1985); theUnited Rubber, Cork, Linoleum & Plastic Workers of America (URW) (1995); the Aluminum, Brick and Glass Workers Union (ABG) (1996); the Canadian Division of the Transportation Communications International Union (1999); and the American Flint Glass Workers Union (AFGWU) (2003).
In June 2004, the USW announced a merger with the 57,000 member Industrial, Wood and Allied Workers of Canada (IWA Canada), a major Canadian forestry workers union. Then in 2005, it announced an even larger merger with the Paper, Allied-Industrial, Chemical and Energy Workers International Union (PACE). The resulting new union adopted its current name after the PACE merger.
In September 2006, the Independent Oil Workers Union of Aruba, which represents refinery workers on the Caribbean island of Aruba, affiliated with the United Steelworkers, becoming the first USW union local outside of the US (including Puerto Rico and the US Virgin Islands) and Canada.
In April 2007, the USW also merged with the Independent Steelworkers Union, adding 1,150 members at Arcelor-Mittal's Weirton, West Virginia steel mill.
In addition to mergers, the USW has also formed strategic alliances with several other unions as well as other groups. In April 2005, the USW and the Alliance of Canadian Cinema, Television and Radio Artists (ACTRA)announced that they had formed a strategic alliance to take on the globalization of the culture industry and to address a range of common issues. In July 2006, the USW announced a similar arrangement...