The Pipeline and Hazardous Materials Safety Administration (PHMSA) has two pipeline safety standards advisory committees that are mandated by legislation. The Natural Gas Pipeline Safety Act of 1968 established the Technical Pipeline Safety Standards Committee (TPSSC), commonly referred to as the Gas Pipeline Advisory Committee (GPAC), and the Hazardous Liquid Safety Act of 1979 established the Technical Hazardous Liquid Pipeline Safety Standards Committee (THLPSSC), .commonly referred to as the Liquid Pipeline Advisory Committee (LPAC).