Great Lakes Centers Home The Occupational Health Service Institute (OHSI)      The Occupational Health Service Institute (OHSI) was established to fulfill the service mission of the Great Lakes Centers. OHSI provides a comprehensive range of occupational and environmental health services to businesses, unions, governmental agencies, communities, and individuals. Current services include an occupational and environmental medicine clinic affiliated with the Association of Occupational and Environmental Clinics; a medical surveillance program; a travelers health and immunization program; a medical advisorship program, and a health hazard evaluation program. OHSI also develops innovative programs to serve special risk populations such as its new "Health in the Arts Program" that serves the needs of anyone working in the arts. OHSI activities are consistent with the service and economic development components of the University of Illinois' mission and especially reflect the Great Cities vision of the University of Illinois at Chicago.