RCW 49.24.310Telephone system for tunnels.Where tunnels are driven from shafts more than two hundred and fifty feet deep, a telephone system shall be established and maintained, communicating with the surface at each such shaft, and with a station or stations readily and quickly accessible to the men at the working level.[ 1941 c 194 s 24; Rem. Supp. 1941 s 7666-32.]
Washington Legal Code