What was originally the Department of Health, became the Department of Health and Environmental Sciences in 1971 with the passage of Governor Anderson’s Executive Reorganization Order 9-71. The Environmental Sciences Division remained part of DHES from that date until 1990, during which time they were responsible for monitoring air quality and water quality, solid waste management, administering the Subdivision Bureau, 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. Currently, the Montana Department of Environmental Quality (DEQ) is comprised of seven divisions: the Director’s Office, Enforcement, Financial Services, Information Technology, Permitting and Compliance, Planning, Prevention, and Assistance, and Remediation.

The functions of the Air Resources Management Bureau were originally covered by the Air Quality Bureau under the umbrella of the Environmental Services Division within DHES. After the creation of the DEQ in 1995, the Air Quality Bureau became the Air and Waste Management Bureau, functioning under the Permitting and Compliance Division and comprised of the Air Permitting and Air Compliance offices. The Air and Waste Management Bureau became the Air Resources Management Bureau (ARMB) in the early 2000s.

The ARMB remains under the umbrella of the Permitting and Compliance Division. On a grand scale, the ARMB regulates air emissions through permitting and compliance activities. This mandate includes: issuing air quality pre-construction and operating permits; inspecting and providing compliance assistance for air emission sources; issuing permits for open burning activities; and coordinating operation of the Montana Smoke Management Program with the major open burning entities.