[Code of Federal Regulations] [Title 40, Volume 26] [Revised as of July 1, 2007] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR280.73] [Page 522] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 280_TECHNICAL STANDARDS AND CORRECTIVE ACTION REQUIREMENTS FOR OWNERS AND Subpart G_Out-of-Service UST Systems and Closure Sec. 280.73 Applicability to previously closed UST systems. When directed by the implementing agency, the owner and operator of an UST system permanently closed before December 22, 1988 must assess the excavation zone and close the UST system in accordance with this subpart if releases from the UST may, in the judgment of the implementing agency, pose a current or potential threat to human health and the environment.