Section 61.209 - Required records(a) Each owner or operator of a phosphogypsum stack must maintain records for each stack documenting the procedure used to verify compliance with the flux standard in § 61.202 , including all measurements, calculations, and analytical methods on which input parameters were based. The required documentation shall be sufficient to allow an independent auditor to verify the correctness of the determination made concerning compliance of the stack with flux standard.(b) Each owner or operator of a phosphogypsum stack must maintain records documenting the procedure used to determine average radium-226 concentration pursuant to § 61.207 , including all measurements, calculations, and analytical methods on which input parameters were based. The required documentation shall be sufficient to allow an independent auditor to verify the accuracy of the radium-226 concentration.(c) Each facility which uses phosphogypsum pursuant to § 61.205 or § 61.206 shall prepare records which include the following information: (1) The name and address of the person in charge of the activity involving use of phosphogypsum.(2) A description of each use of phosphogypsum, including the handling and processing that the phosphogypsum underwent.(3) The location of each site where each use of phosphogypsum occurred, including the suite and/or building number, street, city, county, state, and zip code.(4) The mailing address of each facility using phosphogypsum, if different from paragraph (c)(3) of this section.(5) The date of each use of phosphogypsum.(6) The quantity of phosphogypsum used.(7) The certified average concentration of radium-226 for the phosphogypsum which was used.(8) A description of all measures taken to prevent the uncontrolled release of phosphogypsum into the environment.(9) A description of the disposition of any unused phosphogypsum.(d) These records shall be retained by the facility for at least five years from the date of use of the phosphogypsum and shall be produced for inspection upon request by the Administrator, or his authorized representative.