The McNamara-O’Hara Service Contract Act (SCA) applies to every contract entered into by the United States or the District of Columbia, the principal purpose of which is to furnish services through the use of service employees. The SCA requires contractors and subcontractors performing services on covered federal contracts in excess of $2,500 to pay service employees in various classes no less than the local prevailing wage rates and to furnish fringe benefits found prevailing in the locality. Safety and health standards also apply to such contracts.