RSPA's gas pipeline safety regulations allow certain steel pipelines put into service before the regulations were issued to be operated at pressures that result in a hoop stress higher than 72 percent of the specified minimum yield strength (SMYS) of the pipe. This is the highest hoop stress at which all other steel pipelines subject to the regulations may be operated. Because of accidents involving time-dependent defects on a few gas pipelines operating above 72 percent of SMYS and a National Transportation Safety Board (NTSB) recommendation that RSPA require reductions of hoop stress in those lines, RSPA published an advance notice of proposed rulemaking to invite public participation in determining an appropriate course of action. RSPA has concluded that NTSB's recommended hoop stress reductions would not contribute significantly to pipeline safety. The advance notice is, therefore, withdrawn.