[Code of Federal Regulations] [Title 40, Volume 25] [Revised as of July 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR280.51] [Page 470] TITLE 40--PROTECTION OF ENVIRONMENT AGENCY (CONTINUED) PART 280_TECHNICAL STANDARDS AND CORRECTIVE ACTION REQUIREMENTS FOR OWNERS AND OPERATORS OF UNDERGROUND STORAGE TANKS (UST)--Table of Contents Subpart E_Release Reporting, Investigation, and Confirmation Sec. 280.51 Investigation due to off-site impacts. When required by the implementing agency, owners and operators of UST systems must follow the procedures in Sec. 280.52 to determine if the UST system is the source of off-site impacts. These impacts include the discovery of regulated substances (such as the presence of free product or vapors in soils, basements, sewer and utility lines, and nearby surface and drinking waters) that has been observed by the implementing agency or brought to its attention by another party.