This notice proposes to incorporate by reference sections 2.0, 3.0, and 6.0 of the 1971 (12th) edition of API Standard 1104 "Standard for Welding Pipe Lines and Related Facilities" into the Federal gas pipeline and liquid pipeline safety regulations, respectively Parts 192 and 195 of Title 49 of the Code of Federal Regulations. The notice also proposes certain changes in the regulations which would be necessary if the proposed incorporation by reference of the 12th edition is adopted, as well as editorial modifications for clarity.