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
http://www.agri.idaho.gov/AGRI/Categories/Pesticides/indexPesticides.php
Oregon
http://egov.oregon.gov/ODA/PEST/index.shtml
Washington