Professional Service Industries, also known as PSI, is one of the leading engineering, consulting and testing firms with more than 125 offices throughout the United States. Established in 1881, the company offers scientific, technical and management solutions to public and private sector clients. With over 2,500 employees, it provides site selection, design, construction and property management solutions. The company offers environmental consultation, geotechnical engineering and nondestructive examination services. Professional Service Industries also provides industrial hygiene and construction material testing solutions. The company offers specialty engineering services to consumer, construction and industrial products manufacturers. Its National Client Group develops and manages service programs for national accounts. Professional Service Industries has annual revenues of nearly $240 million and serves clients in the energy, educational, financial, entertainment and hospitality sectors.