Wash. Rev. Code § 70.74.030
All explosive manufacturing buildings and magazines in which explosives or blasting agents except small arms ammunition and smokeless powder are had, kept, or stored, must be located at distances from inhabited buildings, railroads, highways, and public utility transmission systems in conformity with the quantity and distance tables adopted by the department of labor and industries by rule. The department of labor and industries shall adopt the quantity and distance tables promulgated by the federal bureau of alcohol, tobacco, and firearms unless the department determines the tables to be inappropriate. The tables shall be the basis on which applications for storage license[s] are made and storage licenses issued as provided in RCW 70.74.110 and 70.74.120.
RCW 70.74.030