Washington Revised Code Title 49. Labor Regulations § 49.24.240. Inspection after blast

(1) After a blast is fired, loosened pieces of rock shall be scaled from the sides of the excavation and after the blasting is completed, the entire working chamber shall be thoroughly scaled.

(2) The person in charge shall inspect the working chamber and have all loose rock or ground removed and the chamber made safe before proceeding with the work.

(3) Drilling must not be started until all remaining butts of old holes are examined for unexploded charges.