Over the last 25 years of environmental practice, he has represented clients in numerous state and federal Clean Air Act compliance cases (including companies targeted under the current NSR and MACT enforcement initiatives), counseled companies in strategic compliance planning and permitting activities and negotiated hazardous air emission rules and air permitting reforms with the Wisconsin Department of Natural Resources. Currently, Thimke serves as a member of the Wisconsin Department of Natural Resources Advisory Committee developing the Wisconsin counterpart to the recent federal EPA NSR reform regulations.