About 'The Voice of Colorado Subcontractors' Mission The American Subcontractors Association of Colorado is comprised of professional constructors, suppliers and service providers working to bring positive change in the construction industry through advocacy, collaboration, communication and education. Company Overview ASA is a non-profit, membership, trade association representing union and non-union construction subcontractors. Founded in 1966, the national association serves more than 6,500 member companies through a nationwide network of local and state chapters. The ASA Colorado Chapter is located in Denver, with more than 150 member companies.