(1) Fume Class 1. Fume Class 1 explosives must be used for underground operations, as specified by the IME.
(2) Fume Classes 2 and 3. Explosives complying with the requirements of fume Class 2 and 3 may be used if adequate ventilation is provided.
[Statutory Authority: RCW
49.17.010, [49.17].040, and [49.17].050. WSR 02-03-125, § 296-52-67220, filed 1/23/02, effective 3/1/02.]