(1) At any time after reviewing the information submitted pursuant to ARM 17.56.602, 17.56.603, and/or 17.56.604, the department may require owners and operators to submit additional information or to develop and submit a cleanup plan for responding to contaminated soils and groundwater. If a plan is required, owners and operators must submit the plan according to a schedule and format established by the department. Alternatively, owners and operators may, after fulfilling the requirements of ARM 17.56.602 through 17.56.604, choose to submit a cleanup plan for responding to contaminated soil and groundwater. In either case, owners and operators are responsible for submitting a plan that provides for adequate protection of human health, safety, and the environment as determined by the department, and must modify their plan as necessary to meet this standard.

(2) In order to prepare the cleanup plan, owners and operators must properly evaluate and interpret the field and analytical results of the site or remedial investigation to define the extent and magnitude of free product, adsorbed phase product, dissolved phase plume and vapor phase product.

(3) The owners and operators must screen and select cleanup alternatives to develop a matrix evaluation of cleanup alternatives which considers cost, performance, reliability, implementation, safety, and effects on public health and the environment. Information on all cleanup alternatives, with an explanation of why any alternative was selected, must be included in the cleanup plan. Cleanup alternatives may include, but are not limited to, the following types of action:

(a) take no further action;

(b) excavate the contaminated soil and/or treat and/or dispose of the same;

(c) in-place soil treatment;

(d) product recovery;

(e) groundwater removal and treatment;

(f) groundwater gradient control (hydrodynamic);

(g) vapor control measures;

(h) enhanced biodegradation;

(i) drinking water supply replacement;

(j) relocation of affected residences and/or businesses; and

(k) establishment of a petroleum mixing zone in accordance with ARM 17.56.607.

(4) Upon receipt of a cleanup plan from any owner or operator who is or may be seeking reimbursement, the department shall submit a copy of the plan to the appropriate local government office with jurisdiction over corrective action of the release. The office shall respond with any comments within 15 days of receipt of the plan and the department shall approve or disapprove the plan within 15 days of receipt from the local government.

(5) The department will approve the cleanup plan only after ensuring that implementation of the plan will adequately protect human health, safety, and the environment. In making this determination, the department must consider the following factors as appropriate:

(a) the physical and chemical characteristics of the regulated substance, including its toxicity, persistence, and potential for migration;

(b) the hydrogeologic characteristics of the facility and the surrounding area;

(c) the proximity, quality, and current and future uses of nearby surface water and groundwater;

(d) the potential effects of residual contamination on nearby surface water and groundwater;

(e) an exposure assessment that identifies routes by which receptors may be exposed to contaminants and estimates contaminant concentrations to which receptors may be exposed; and

(f) any information assembled in compliance with this subchapter.

(6) Within 30 days of department approval of the cleanup plan or as directed by the department, owners and operators must implement the plan, including any modifications made by the department to the plan. Owners and operators must monitor, evaluate, and report the results of implementing the plan in accordance with a schedule and in a format established by the department. During implementation of the cleanup plan, a status letter shall be submitted quarterly to the department. The cleanup plan must contain a plan and schedule for compliance monitoring to evaluate the effectiveness of cleanup activities. Compliance monitoring must continue for a period of at least two years after completion of cleanup activities specified in the cleanup plan, or another reasonable time period approved by the department. Results of compliance monitoring will be evaluated by the department on a site-specific basis and compared to cleanup goals that should be outlined in the cleanup plan. Final completion of cleanup activities and compliance monitoring must be approved by the department.

(7) Owners and operators may, in the interest of minimizing environmental contamination and promoting more effective cleanup, begin cleanup of soil and groundwater before the cleanup plan is approved provided that they:

(a) notify the department of their intention to begin cleanup;

(b) comply with any conditions imposed by the department, including halting cleanup or mitigating adverse consequences from cleanup activities; and

(c) incorporate these self-initiated cleanup measures in the cleanup plan that is submitted to the department for approval.

(8) As part of corrective action, owners and operators must conduct restoration activities as soon as the completion of any part of the cleanup plan will allow. Restoration activities must include:

(a) restoring utility services disrupted as a result of investigative or corrective action activities;

(b) properly abandon or reclaim recovery and monitoring systems, including any wells, in accordance with state law or rules, after recovery and monitoring operations are terminated. Proper abandonment and reclamation includes reclamation of recovery culverts, infiltration galleries, electrical systems and plumbing systems, and landscaping necessary to restore any disturbed property to its precorrective action state.