International Union of Operating Engineers (IUOE) is a diversified trade union that primarily represents operating engineers. Founded in 1896, the organization has over 400,000 members in 138 local unions throughout the United States and Canada. IUOE is the 12th largest union in the AFL-CIO. The organization operates boilers, generators, heating and cooling systems, as well as maintains the buildings and grounds. IUOE works in private industry and in various areas of public employment, such as hospitals, nursing homes, schools and government complexes.