{"data":{"id":"us-mt/75-11-508","jurisdiction":"us-mt","citation":"75-11-508","heading":"Corrective action -- petroleum mixing zones.","body":"(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.\n(2) If a petroleum mixing zone is included in a corrective action plan, it may be established only when:\n(a) all source material has been removed to the maximum extent practicable;\n(b) the extent of petroleum contamination has been defined;\n(c) natural breakdown or attenuation is occurring within the plume; and\n(d) no further corrective action is reasonably required at the site.\n(3) The boundary of a petroleum mixing zone established in accordance with this section must be contained within the boundary of the property on which the petroleum release originated unless a recorded easement, a restrictive covenant, or another institutional control approved by the department on an adjoining property allows the petroleum mixing zone to extend onto the adjoining property.\n(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.\n(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 pursuant to 75-5-301.\n(6) If a petroleum mixing zone is established and maintained:\n(a) the petroleum release is considered resolved;\n(b) no further corrective action for the petroleum release is required; and\n(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.\n(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.","path":["TITLE 75. ENVIRONMENTAL PROTECTION","CHAPTER 11. UNDERGROUND STORAGE TANKS","Part 5. Montana Underground Storage Tank Act"],"source_url":"https://mca.legmt.gov/bills/mca/title_0750/chapter_0110/part_0050/section_0080/0750-0110-0050-0080.html","current_through":"Montana Code Annotated 2025","vintage":"","retrieved_at":"2026-09-14T04:59:53Z","sha256":"41ac48fc44ad5e147205787fb3b8bd3f74dc3e8343c7b2d1cec96cd7aaf1ed31","source_id":"us-mt","stale":false,"prev":"us-mt/75-11-506","next":"us-mt/75-11-509"},"notice":"GroundRules: Original legal text. Not legal advice."}