Created as part of the Department of Health and Environmental Sciences in 1973, the Environmental Sciences Division remained part of DHES from 1974 to 1990, during which time they were responsible for monitoring air quality and water quality, solid waste management, administering the Subdivision Bureau, and ensuring food and consumer safety, and occupational health. In 1991, though still a part of the Department of Health and Environmental Sciences, the role of the Environmental Sciences Division was considerably expanded to include: Natural Resource Damage Assessment, a Petroleum Tank Release Compensation Board, a Superfund Section, and an Underground Storage Tanks Section.

The Environmental Sciences Division became its own separate department, renamed the Department of Environmental Quality, in 1995, and was comprised of the following divisions: Director’s Office, Air Quality, Centralized Services, Energy, Environmental Remediation, Reclamation, Waste Management, and Water Quality. Under DHES’s Centralized Services, the Office of Information Technology had been referred to as the Information Services Bureau; after the split in 1995, the ISB became the DEQ, Information Technology Bureau. In 2000, the ITB became the Systems Administration Bureau and the Systems Solutions Bureau. In 2004, the Systems Administration Bureau and the Systems Solutions Bureau were rejoined as Information Technology Services.

What is currently referred to as the Office of Information Technology (OIT) functions as part of the Deputy Director’s office, and exists to provide systems administration, applications development and support services to the department and its regional offices. The office is responsible for the planning, development, implementation and maintenance of comprehensive statewide information technology solutions. Responsibilities include short term and long range planning, management reporting, budgetary planning, resource allocation, and development of policies and procedures. The Office of Information Technology is also responsible for administration of the department's web sites.