The Operative Plasterers' and Cement Masons' International Association, also known as OPCMIA, is a labor union that represents plasterers and cement masons in the construction industry throughout North America. Established in 1864, it is one of the oldest building and construction trade unions in the United States. The Operative Plasterers' and Cement Masons' International Association offers a range of training programs that includes topics related to occupational heath and workplace safety, as well as continuing education for instructors and hands-on apprenticeship sessions. It provides group health insurance plans that provide medical care services for members and families. Additionally, the association maintains an online store that offers T-shirts, denim shirts, jackets and wrist watches for men and ladies.