Established in 1881, Professional Service Industries Inc. is one of the leading engineering, consulting and testing firms in the United States. Located in Harrisburg, Pa., the company offers a range of services, such as environmental consulting, industrial hygiene and indoor-air quality services, construction materials testing engineering and geo-technical engineering. It caters to education, commercial development and entertainment industries. The company is a member of the U.S. Green Building Council (USGBC) and American Association for Laboratory Accreditation (A2LA).