Operative Plasterers' and Cement Masons' International Association
The Operative Plasterers' and Cement Masons' International Association of the United States and Canada (OPCMIA) is a trade union of plasterers and cement masons in the construction industry in the United States and Canada.Members of the union finish interior walls and ceilings of buildings and apply plaster on masonry, metal, and wire lath or gypsum.Cement masons are responsible for all concrete construction, including pouring and finishing of slabs, steps, wall tops, curbs and gutters, sidewalks, and paving.The modern organization was formed in 1882, when a number of locals who had supported the Cincinnati, Ohio local in a strike earlier that year met in St. Louis, Missouri, to reestablish a national organization.The union trained a large number of veterans of World War II in its apprenticeship programs, while curtailing the competition from non-union contractors.