Section 160.25 - Implementation of responses for specific sites; enforcement standards(1)(a) If an activity or practice is not subject to regulation under chs. 283 or 289 to 292 and if the concentration of a substance in groundwater attains or exceeds an enforcement standard at a point of standards application, the regulatory agency shall take the following responses unless it can be shown to the regulatory agency that, to a reasonable certainty, by the greater weight of the credible evidence, an alternative response will achieve compliance with the enforcement standard at the point of standards application: 1. Prohibit the activity or practice which uses or produces the substance; and2. Implement remedial actions with respect to the specific site in accordance with rules promulgated under s. 160.21.(b) A regulatory agency shall impose a remedial action for a specific site which is reasonably related in time and scope to the substance, activity or practice which caused the enforcement standard to be attained or exceeded at the point of standards application.(2) If a facility is subject to regulation under chs. 283 or 289 to 292 and if the concentration of a substance in groundwater attains or exceeds an enforcement standard at a point of standards application, the department shall require remedial actions for a specific site in accordance with rules promulgated under s. 160.21 as are necessary to achieve compliance with the enforcement standard at the point of standards application.(3) If nitrates or any substance of aesthetic concern only attains or exceeds an enforcement standard, the regulatory agency is not required to impose a prohibition or close a facility if it determines that: (a) The enforcement standard was attained or exceeded, in whole or in part, because of high background concentrations of the substance; and(b) The additional concentration does not represent a public welfare concern.(4) If compliance with the enforcement standard is achieved at the point of standards application, s. 160.23 applies.(5)(a) A regulatory agency shall consider the existence of background concentrations of naturally occurring substances in evaluating response options to the noncompliance with an enforcement standard for that substance. A regulatory agency may not order remedial action under sub. (1) or (2) at a site where the background concentration of a substance is determined to be equal to or greater than the preventive action limit, unless the regulatory agency determines that the proposed remedial action will result in the protection of or substantial improvement in groundwater quality notwithstanding the background concentrations of naturally occurring substances.(b) Paragraph (a) does not apply to a substance which is carcinogenic, teratogenic or mutagenic in humans.(6) If the concentration of a substance in groundwater attains or exceeds an enforcement standard at a point of standards application and if a waste facility subject to the waste management fund incurs costs for repairing environmental damage which arises from those occurrences which are not anticipated in the plan of operation and which poses a substantial hazard to public health or welfare, those costs may be paid as provided under s. 289.68.(7) An action under this section with respect to a specific site does not constitute a major state action under s. 1.11(2).1983 a. 410; 1995 a. 227.