Washington Revised Code Title 84. Property Taxes § 84.36.477. Business inventories

(A) All grains and flour, fruit and fruit products, unprocessed timber, vegetables and vegetable products, and fish and fish products, while being transported to or held in storage in a public or private warehouse or storage area if actually shipped to points outside the state on or before April 30th of the first year for which they would otherwise be taxable;

(B) All finished plywood, hardboard, and particleboard panels shipped from outside this state to any processing plant within this state, if the panels are moving under a through freight rate to final destination outside this state and the carrier grants the shipper the privilege of stopping the shipment in transit for the purpose of storing, milling, manufacturing, or other processing, while the panels are in the process of being treated or shaped into flat component parts to be incorporated into finished products outside this state and for thirty days after completion of the processing or treatment;

(C) All ore or metal shipped from outside this state to any smelter or refining works within this state, while in process of reduction or refinement and for thirty days after completion of the reduction or refinement; and

(D) All metals refined by electrolytic process into cathode or bar form while in this form and held under negotiable warehouse receipt in a public or private warehouse recognized by an established incorporated commodity exchange and for sale through the exchange.