75-11-508. Corrective action -- petroleum mixing zones. (1) A corrective action plan prepared pursuant to 75-11-309 may include the use of a petroleum mixing zone, as defined in 75-11-503, in conjunction with the final remediation and resolution of a petroleum release.
     (2) If a petroleum mixing zone is included in a corrective action plan, it may be established only when:
     (a) all source material has been removed to the maximum extent practicable;
     (b) the extent of petroleum contamination has been defined;
     (c) natural breakdown or attenuation is occurring within the plume; and
     (d) no further corrective action is reasonably required at the site.
     (3) The boundary of a petroleum mixing zone established in accordance with this section must be contained within the:
     (a) boundary of the property on which the petroleum release originated unless a recorded easement on an adjoining property allows the petroleum mixing zone to extend onto the adjoining property; and
     (b) unconfined aquifer.
     (4) Monitoring of a petroleum mixing zone may not be required unless there is a unique, overriding, site-specific, impact-related reason to require monitoring.
     (5) At the downgradient boundary of a petroleum mixing zone, the concentration of any petroleum constituent, including benzene, may not exceed a water quality standard adopted by the board pursuant to 75-5-301.
     (6) If a petroleum mixing zone is established and maintained:
     (a) the petroleum release is considered to be resolved;
     (b) no further corrective action for the petroleum release is required; and
     (c) the department shall issue a no-further-action letter to the owner or operator stating that a petroleum mixing zone has been established for the release and describing any conditions required to maintain the petroleum mixing zone.
     (7) A corrective action plan approved by the department pursuant to 75-11-309 may be amended to include a petroleum mixing zone in accordance with this section, including a corrective action plan approved prior to April 15, 2011.

     History: En. Sec. 5, Ch. 189, L. 2011.