More rigid standards were proposed for the frequency and location of leakage surveys to reduce the risk of damage from gas pipeline leaks outside business districts. Also, specific procedures were proposed for conducting leakage surveys on petroleum gas systems. Subsequent review shows that because of the normally short time between the occurrence of leaks and ensuing accidents, the proposed more frequent surveys would not be cost effective in reducing risk. Similarly, the benefits of the proposed petroleum gas procedures are indefinite. As a consequence, the proposed standards are withdrawn.