RCW 15.58.050: Registration of pesticides—Generally.

Every pesticide which is distributed within this state or delivered for transportation or transported in intrastate commerce or between points within this state through any point outside this state shall be registered with the director subject to the provisions of this chapter. However, registration is not required if: A pesticide is shipped from one plant or warehouse to another plant or warehouse operated by the same person and used solely at such plant or warehouse as a constituent part to make a pesticide which is registered under the provisions of this chapter; or a written permit has been obtained from the director to distribute or use the specific pesticide for experimental purposes subject to restrictions and conditions set forth in the permit.