(1) Within 90 days after a determination is made pursuant to ARM 17.50.1307 that a constituent listed in Appendix II to 40 CFR Part 258 (July 1, 2008) has been detected at a statistically significant level exceeding the ground water protection standards defined under ARM 17.50.1307(8), the owner or operator of a facility shall:
(a) initiate an assessment of corrective measures; and
(b) submit to the department for approval an assessment of corrective measures that addresses the criteria listed in (3).
(2) The owner or operator shall continue to monitor in accordance with the assessment monitoring program as specified in ARM 17.50.1307.
(3) The assessment in (1) must include an analysis of the effectiveness of potential corrective measures in meeting all of the requirements and objectives of the remedy as described under ARM 17.50.1309, addressing at least the following:
(a) the performance, reliability, ease of implementation, and potential impacts of appropriate potential remedies, including safety impacts, cross-media impacts, and control of exposure to any residual contamination;
(b) the time required to begin and complete the remedy;
(c) the costs of remedy implementation; and
(d) the institutional requirements such as state or local permit requirements or other environmental or public health requirements that may substantially affect implementation of the remedy(s).
(4) Prior to the selection of a remedy, the owner or operator shall discuss the results of the corrective measures assessment in a public meeting with interested and affected parties.