Summary: Staff investigation of new 12-inch high pressure natural gas line in Mason County. The 2.6 mile line will run from Goldsborough Creek southwest of Shelton to an existing regulator facility on John's Prairie Rd. The new pipeline has been designed to operate at a maximum design pressure of 720 psig, but will initially be limited to 499 psig. Cascade Natural Gas has asked for Commission authorization to operate the new line at 720 psig, within proximity to buildings intended for human occupancy, as described in WAC 480-93-020.