The specific laws and regulations governing use, storage, disposal, and transportation of pesticides differ slightly in each northwestern state. Before you use pesticides, obtain a copy of the detailed pesticide use laws and rules for the state(s) in which you are operating. The state-specific pesticide laws and rules can be found at each state department of agriculture website.
Idaho
https://agri.idaho.gov/main/56-2/pesticides/
For regulations on hazardous waste
Department of Environmental Quality
1410 North Hilton
Boise, ID 83706-1255
208-373-0502; http://www.deq.state.id.us/
Oregon
https://www.oregon.gov/oda/programs/Pesticides/Pages/AboutPesticides.aspx
Washington
https://agr.wa.gov/departments/pesticides-and-fertilizers/pesticides