(1) This rule is applicable to spills or unanticipated discharges of pesticides, herbicides, other toxic substances or any other materials that would lower the quality of any ground waters of the state below Montana ground water quality standards.

(2) The owner, operator, or person responsible for a spill or unanticipated discharge must notify the department as soon as possible by contacting the Montana Disaster and Emergency Services 24-hour duty officer [(406)324-4777], and provide all relevant information about the spill.

(3) Pursuant to 75-5-621 and 75-5-622 , MCA, and depending on the severity of the spill or accidental discharge, the department may require the owner or operator to:

(a) take immediate remedial measures;

(b) monitor the direction, depth and rate of movement of any contaminated ground waters and of the spilled or discharged material;

(c) determine the probable impact, including the duration of impact, on existing water supply wells, springs, and anticipated future beneficial uses of the ground water supply impacted;

(d) determine the probable impact, including the duration of impact, on surface waters that may be affected by contaminated ground waters; or

(e) provide alternate water supplies to existing water uses disrupted by the spill or unanticipated discharge.

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