Chapter NR 140

NR 140.24(1)(b) (b) Upon receipt of the notice under par. (a), the department shall evaluate the information and, if further information is required to make the assessment under par. (c), direct the owner or operator to prepare and submit a report by a specified deadline. The report shall assess the cause and significance of the increased concentration based on a consideration of the factors identified in par. (c) and shall propose a response to meet the objectives of sub. (2).

NR 140.24(1)(c) (c) The department shall assess the cause and significance of the concentration of the substance in determining the appropriate response to meet the objectives of sub. (2). In addition to all other relevant information, the department shall consider the information submitted under par. (b) and the following factors where applicable:

NR 140.24(1)(c)1. 1. Background water quality.

NR 140.24(1)(c)1.a. a. The department shall compare background water quality data and monitoring data from wells downgradient of the facility, practice or activity to determine if downgradient water quality is adversely affected. If the background water quality at a facility, practice or activity is not known or is inadequately defined, the department may require additional sampling of existing wells, or installation and sampling of additional wells, or both.

NR 140.24(1)(c)1.b. b. Except for substances which are carcinogenic, teratogenic or mutagenic in humans, before requiring a response at a site where the background concentration of a substance is determined to be equal to or greater than the preventive action limit, the department shall determine that the proposed remedial action will protect or substantially improve groundwater quality notwithstanding the background concentrations of naturally occurring substances.

NR 140.24(1)(c)2. 2. Reliability of sampling data. As part of its review of the quality of the sampling data, the department shall evaluate the sampling procedures, precision and accuracy of the analytical test, size of the data set, and the quality control and quality assurance procedures used. If there is insufficient information to evaluate the reliability of the sampling data, the department may require additional samples or other changes in the monitoring program at the facility, practice or activity.

NR 140.24(1)(c)3. 3. Public health, welfare and environmental effects of the substance. The department shall consider the public health, welfare and environmental effects of the substance, including but not limited to its mobility in the subsurface, environmental fate, the risks considered when the standard was adopted and whether it is carcinogenic, mutagenic, teratogenic or has interactive effects with other substances.

NR 140.24(1)(c)4. 4. Probability that a preventive action limit or an enforcement standard may be attained or exceeded outside the design management zone. In evaluating the probability that a preventive action limit or an enforcement standard may be attained or exceeded outside the design management zone, the department shall consider, at a minimum, geologic conditions, groundwater flow rate and direction, contaminant mobility in the subsurface and environmental fate.

NR 140.24(1)(c)5. 5. Performance of the facility, practice or activity. The department shall consider whether the facility, practice or activity is performing as designed in accordance with the design requirements in s. NR 140.22 (1). The department shall consider the type, age and size of the facility, practice or activity; the type of design, if applicable; the operational history; and other factors related to performance of the facility, practice or activity as appropriate.

NR 140.24(1)(c)6. 6. Location of the monitoring point. The department shall consider the location of the monitoring point in relation to the facility, practice or activity and the design management zone in assessing the appropriate response.

NR 140.24(1)(c)7. 7. Other known or suspected sources of the substance in the area. If other known or suspected sources are present in the vicinity of a facility, practice or activity of concern, the department shall evaluate the probability of contributions from other sources of the substance. The department shall consider, at a minimum, the number, size, type and age of nearby sources; the groundwater flow patterns; and the substances involved.

NR 140.24(1)(c)8. 8. Hydrogeologic conditions. The department shall consider the geologic and groundwater conditions, including but not limited to the nature, thickness and permeability of the unconsolidated materials; the nature and permeability of bedrock; the depth to the water table; groundwater flow gradients, both vertical and horizontal; the position of the facility, practice or activity within the groundwater flow system; and the present and potential groundwater use in the vicinity of the facility, practice or activity at which an exceedance occurs. If there is insufficient hydrogeologic information, the department may require additional information.

NR 140.24(1)(c)9. 9. Extent of groundwater contamination. The department shall consider the current and anticipated future extent of groundwater contamination in 3 dimensions. If water supplies are affected or threatened, the department shall evaluate the existing effects and potential risks of the substance on the potable water supplies. If the extent of contamination is not known, the department may require further documentation of the extent of contamination.

NR 140.24(1)(c)10. 10. Alternate responses. The department shall evaluate alternate responses, including consideration of the technical and economic feasibility of alternate responses from Table 5 or 6 or both, the practicality of stopping the further release of the substance and the risks and benefits of continued operation of the facility, practice or activity and the ability of a response to meet other applicable environmental protection laws.

NR 140.24(2) (2) Response objectives. Based on its evaluation of the report required under sub. (1), and the assessment criteria of sub. (1) (c), the department shall specify the responses to be implemented by the owner or operator of the facility, practice or activity designed to the extent technically and economically feasible to prevent any new releases of the substance from traveling beyond the design management zone or other applicable points of standards application described in s. NR 140.22 and restore contaminated groundwater within a reasonable period of time, considering the criteria specified in s. NR 722.07. Both the source control and the groundwater restoration components of the response shall be designed and implemented to:

NR 140.24(2)(a) (a) Minimize the concentration of the substance in groundwater at the point of standards application where technically and economically feasible;

NR 140.24(2)(b) (b) Regain and maintain compliance with the preventive action limit. If the department determines that compliance with the preventive action limit is either not technically or economically feasible, the owner or operator shall achieve compliance with the lowest possible concentration which is technically and economically feasible; and

NR 140.24(2)(c) (c) Ensure that the enforcement standard is not attained or exceeded at the point of standards application.

NR 140.24(3) (3) Range of responses for indicator parameters. Except as otherwise provided in this subsection, the range of responses that the department may take or may require if a preventive action limit for an indicator parameter identified in Table 3 has been attained or exceeded, is one or more of the responses in items 1 to 4 in Table 5. If total coliform bacteria are detected at a facility, practice, or activity groundwater monitoring point, that monitoring point shall be sampled for E. coli bacteria. The range of responses that the department may take or may require if a preventive action limit for total coliform bacteria has been attained or exceeded, is one or more of the responses in Table 5. The range of responses is one or more of the responses in items 1 to 6 of Table 5 in the event the department determines that:

NR 140.24(3)(a) (a) There is a threat to public health or welfare as a result of a preventive action limit for an indicator parameter being attained or exceeded; or

NR 140.24(3)(b) (b) The results demonstrate a significant design flaw or failure of the facility to contain substances, such that the facility can be expected to emit one or more of the substances on Table 1 or 2 in excess of a preventive action limit at a point of standards application.

NR 140.24(4) (4) Range of responses for substances of public health or welfare concern. The range of responses which the department may take or may require the owner or operator of a facility, practice or activity to take if a preventive action limit for a substance of health or welfare concern has been attained or exceeded are listed in Table 5. More than one response may be taken or required by the department.

NR 140.24(5) (5) No action response criteria. For facilities, practices and activities with a design management zone specified in s. NR 140.22 (3) Table 4, the department may determine that no response is necessary and that an exemption under s. NR 140.28 is not required when either of the following conditions is met:

NR 140.24(5)(a) (a) The concentration of a substance within a design management zone is detected above the preventive action limit, the enforcement standard has not been attained or exceeded within the design management zone, and the department determines that there is no indication that the preventive action limit will be attained or exceeded at any point outside the design management zone, or

NR 140.24(5)(b) (b) The background concentration of a substance is greater than the preventive action limit, the anticipated or detected incremental increase in the concentration of a substance which results from a specific facility, practice or activity is not greater than the preventive action limit, and the anticipated or detected concentration is not greater than the enforcement standard either within or outside of the design management zone.

NR 140.24(6) (6) Prohibition and closure criteria. The department may not impose a prohibition on a practice or activity or require closure of a facility which produces the substance unless the department:

NR 140.24(6)(a) (a) Bases its decision upon reliable test data;

NR 140.24(6)(b) (b) Determines, to a reasonable certainty, by the greater weight of the credible evidence, that no other remedial action would prevent the violation of the enforcement standard at the point of standards application;

NR 140.24(6)(c) (c) Establishes the basis for the boundary and duration of the prohibition; and

NR 140.24(6)(d) (d) Ensures that any prohibition imposed shall be reasonably related in time and scope to maintaining compliance with the enforcement standard at the point of standards application.

NR 140.24 History History: Cr. Register, September, 1985, No. 357, eff. 10-1-85; am. (5) (intro.) and (6) (intro.), Register, October, 1988, No. 394, eff. 11-1-88; am. (1) (intro.), (a), (b), (c) (intro.), 5. and 10., (2) (intro.), and (5) (intro.), renum. (7) to be NR 104.02 (4), Register, January, 1992, No. 433, eff. 2-1-92; am. (1) (intro.), (c) (intro.), (3) (intro.) and Table 5, Register, March, 1994, No. 459, eff. 4-1-94; am. (1) (a), (5) (intro.), Register, August, 1995, No. 476, eff. 9-1-95; am. (2) (intro.), (4) and Table 5, Register, October, 1996, No. 490, eff. 11-1-96; am. (1) (a), Register, December, 1998, No. 516, eff. 1-1-99; CR 22-061: am. (3) (intro.) Register July 2023 No. 811, eff. 8-1-23.

NR 140.26 NR 140.26 Responses when an enforcement standard is attained or exceeded.

NR 140.26(1) (1) Notification and assessment. If the concentration of a substance in groundwater attains or exceeds an enforcement standard at a point of standards application as described in s. NR 140.22 (2):

NR 140.26(1)(a) (a) The owner or operator of the facility, practice or activity shall notify the department in writing when monitoring data is submitted that an enforcement standard has been attained or exceeded in accordance with any deadlines in applicable statutes, rules, permits or plan approvals. Where no deadlines are imposed, the owner or operator shall notify the department as soon as practical after the results are received. When the results of any private well sampling attain or exceed an enforcement standard or preventive action limit, the owner or operator of the facility, practice or activity shall notify the department within 10 days after the results are received. The notification shall provide a preliminary analysis of the cause and significance of the concentration.

NR 140.26 Note Note: Section 292.11 (2) (a), Stats., requires that the department be notified immediately of hazardous substance discharges.

NR 140.26 Note Note: See s. NR 140.27.

NR 140.26(1)(b) (b) Upon receipt of the notice under par. (a), the department shall evaluate the information and, if further information is required to make the assessment under par. (c), direct the owner or operator to prepare and submit a report by a specified deadline. The report shall assess the cause and significance of the increased concentration based on a consideration of the factors identified in s. NR 140.24 (1) (c) and shall propose a response to achieve compliance with the enforcement standard at the point of standards application and to comply with sub. (4).

NR 140.26(1)(c) (c) The department shall assess the cause and significance of the concentration of the substance in determining the appropriate response measures to achieve compliance with the enforcement standard at the point of standards application and to comply with sub. (4). In addition to all other relevant information, the department shall consider the information submitted under sub. (1) and the factors listed in s. NR 140.24 (1) (c), where applicable.

NR 140.26(2) (2) Regulatory responses.

NR 140.26(2)(a) (a) If a facility, activity or practice is regulated under subch. IV of ch. 283, Stats., ch. 289, 291, or 292, Stats., the department shall require responses as necessary, based on the evaluation of the increased concentration as outlined in sub. (1), to prevent any new releases of the substance from traveling beyond the design management zone or other applicable point of standards application described in s. NR 140.22 and restore contaminated groundwater within a reasonable period of time, considering the criteria specified in s. NR 722.07. Both the source control and the groundwater restoration components of the response shall be designed to achieve compliance with the enforcement standard at the point of standards application and to achieve compliance with the preventive action limit at the point of standards application unless compliance with the preventive action limit is not technically and economically feasible. The range of responses which the department may take or may require the owner or operator of a facility, practice or activity to take if an enforcement standard for a substance of public health or welfare concern has been attained or exceeded at a point of standards application is listed in Table 6. More than one response listed in Table 6 may be required by the department. In addition, the department may take or may require the owner or operator of a facility, practice or activity to take one or more responses from Table 5, except response number one.

Table 6

Range of Responses for Exceedance of Enforcement Standards for Substances of Health or Welfare Concern

NR 140.26(2)(b) (b) If an activity or practice is not subject to regulation under subch. IV of ch. 283, Stats., ch. 289, 291, or 292, Stats., and if the concentration of a substance in groundwater attains or exceeds an enforcement standard at a point of standards application, the department shall take the following responses unless it can be shown to the department 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:

NR 140.26(2)(b)1. 1. Prohibit the activity or practice which uses or produces the substance; and

NR 140.26(2)(b)2. 2. Require remedial actions with respect to the specific site in accordance with this chapter.

NR 140.26(3) (3) Responses for nitrate and substances of public welfare concern. If nitrates or any substance of welfare concern only attains or exceeds an enforcement standard, the department is not required to impose a prohibition or close a facility if it determines that:

NR 140.26(3)(a) (a) The enforcement standard was attained or exceeded, in whole or in part, because of high background concentrations of the substance; and

NR 140.26(3)(b) (b) The additional concentration does not represent a public welfare concern.

NR 140.26(4) (4) Compliance with preventive action limits. When compliance with the enforcement standard is achieved at the point of standards application, s. NR 140.24 applies.

NR 140.26 History History: Cr. Register, September, 1985, No. 357, eff. 10-1-85; am. (1) (intro.), (a), (b), (2), r. (6), Register, January, 1992, No. 433, eff. 2-1-92; am. (1) (intro.) and Table 6, renum. (2) to (5) to be (2) (a), (b), (3) and (4), Register, March, 1994, No. 459, eff. 4-1-94; am. (1) (a), Register, August, 1995, No. 476, eff. 9-1-95; correction in (1) (b) and (c) made under s. 13.93 (2m) (b) 7., Stats., Register, August, 1995, No. 476; am. (2) (a) and Table 6, Register, October, 1996, No. 490, eff. 11-1-96; am. (1) (a), Register, December, 1998, No. 516, eff. 1-1-99; correction in (2) (a), (b) (intro.) made under s. 13.92 (4) (b) 7., Stats., Register February 2017 No. 734.

NR 140.27 NR 140.27 Responses when an enforcement standard is attained or exceeded at a location other than a point of standards application. If the concentration of a substance in groundwater attains or exceeds an enforcement standard at a location other than a point of standards application for an enforcement standard, s. NR 140.24 shall apply.

NR 140.27 History History: Cr. Register, October, 1988, No. 394, eff. 11-1-88.

NR 140.28 NR 140.28 Exemptions.

NR 140.28(1) (1) Applicability.

NR 140.28(1)(a) (a) The department may not approve a proposed facility, practice or activity at a location where a preventive action limit or enforcement standard adopted under s. NR 140.10 or 140.12 has been attained or exceeded unless an exemption has been granted under this section.

NR 140.28(1)(b) (b) For an existing facility, practice or activity, a response is required under s. NR 140.24 (2) or 140.26 (2) when a preventive action limit or an enforcement standard has been attained or exceeded at a point of standards application unless an exemption has been granted under this section or the criteria of s. NR 140.24 (5) (a) or (b) are met.

NR 140.28(1)(c) (c) For an existing facility, practice or activity that has taken or is taking a response under s. NR 140.24 (2) or 140.26 (2), a continued response is required unless a substance no longer attains or exceeds a preventive action limit or an exemption has been granted under this section.

NR 140.28(1)(d) (d) If a substance or remedial material is to be infiltrated or injected into groundwater at a concentration which attains or exceeds a preventive action limit, or at any concentration for a substance or remedial material for which a groundwater quality standard has not been established under this chapter, a temporary exemption is required under sub. (5).

NR 140.28(2) (2) Criteria for granting exemptions where the background concentration is below the preventive action limit.

NR 140.28(2)(a) (a) The department may grant an exemption under this section to a facility, practice or activity which is regulated by the department in an area where the background concentration of nitrate or a substance of public welfare concern is below the preventive action limit if the facility, practice or activity is designed and implemented to achieve the lowest possible concentration for that substance which is technically and economically feasible and the existing or anticipated increase in the concentration of that substance does not present a threat to public health or welfare.

NR 140.28(2)(b) (b) The department may grant an exemption under this section to a facility, practice or activity which is regulated by the department in an area where the background concentration of a substance of public health concern, other than nitrate, is below the preventive action limit for that substance if all of the following occur:

NR 140.28(2)(b)1. 1. The measured or anticipated increase in the concentration of the substance will be minimized to the extent technically and economically feasible.

NR 140.28(2)(b)2. 2. Compliance with the preventive action limit is either not technically or economically feasible.

NR 140.28(2)(b)3. 3. The enforcement standard for that substance will not be attained or exceeded at the point of standards application.

NR 140.28(2)(b)4. 4. Any existing or projected increase in the concentration of the substance above the background concentration does not present a threat to public health or welfare.

NR 140.28 Note Note: An exemption may be considered under this subsection even if monitoring data indicates no detectable background concentration of the substance.

NR 140.28(3) (3) Criteria for granting exemptions where the background concentration is above a preventive action limit.

NR 140.28(3)(a) (a) The department may grant an exemption under this section to a facility, practice or activity which is regulated by the department in an area where the background concentration of nitrate or a substance of public welfare concern attains or exceeds the preventive action limit if the facility, practice or activity is designed to achieve the lowest possible concentration for that substance which is technically and economically feasible and the existing or anticipated increase in the concentration of the substance does not present a threat to public health or welfare.

NR 140.28(3)(b) (b) The department may grant an exemption under this section to a facility, practice or activity which is regulated by the department in an area where the background concentration of a substance of public health concern, other than nitrate, attains or exceeds a preventive action limit for that substance:

NR 140.28(3)(b)1. 1. If the facility, practice or activity has not caused and will not cause the further release of that substance into the environment; or

NR 140.28(3)(b)2. 2. If the background concentration of the substance does not exceed the enforcement standard for that substance, the facility, practice or activity has not caused and will not cause the concentration of the substance to exceed the enforcement standard for that substance at a point of standards application and the facility, practice or activity is designed to achieve the lowest possible concentration of that substance which is technically and economically feasible.

NR 140.28(4) (4) Criteria for granting exemptions where the background concentration is above an enforcement standard.

NR 140.28(4)(a) (a) The department may grant an exemption under this section to a facility, practice or activity which is regulated by the department in an area where the background concentration of nitrate or a substance of public welfare concern attains or exceeds an enforcement standard if the facility, practice or activity is designed to achieve the lowest possible concentration for that substance which is technically and economically feasible and the existing or anticipated increase in the concentration of the substance does not present a threat to public health or welfare.

NR 140.28(4)(b) (b) The department may grant an exemption under this section to a facility, practice or activity which is regulated by the department in an area where the background concentration of a substance of public health concern, other than nitrate, attains or exceeds the enforcement standard for that substance if:

NR 140.28(4)(b)1. 1. The facility has not caused and will not cause the further release of that substance into the environment; or

NR 140.28(4)(b)2. 2.

NR 140.28(4)(b)2.a. a. The facility is designed to achieve the lowest possible concentration of that substance which is technically and economically feasible; and

NR 140.28(4)(b)2.b. b. The existing or anticipated increase in the concentration of the substance has not caused or will not cause an increased threat to public health or welfare; and

NR 140.28(4)(b)2.c. c. The existing or anticipated incremental increase in the concentration of the substance by itself, has not exceeded or will not exceed the preventive action limit.

NR 140.28(4)(c) (c) The department shall take action under s. NR 140.26 if it determines that the increase in the concentration of the substance causes an increased threat to public health or welfare or it determines that the incremental increase in the concentration of the substance, by itself, exceeds the preventive action limit.

NR 140.28(5) (5) Criteria for granting a temporary exemption where infiltration or injection is utilized for a remedial action.

NR 140.28(5)(a) (a) General. In lieu of an exemption granted in compliance with the criteria in subs. (2) to (4), the department may grant a temporary exemption if the criteria in this subsection are complied with. This exemption applies to the owner or operator of a facility, practice or activity that is undertaking a remedial action that: includes the infiltration or injection of contaminated groundwater or remedial material, has been approved by the department, and will comply with the applicable response objectives under s. NR 140.24 or 140.26 within a reasonable period of time. The owner or operator of the facility, practice or activity may submit a temporary exemption request to the department at the same time or after the department has approved the remedial action.

NR 140.28(5)(b) (b) Exemption request. The owner or operator of the facility, practice or activity shall submit a request for a temporary exemption to the department. As part of the request, the applicant shall indicate how the exemption prerequisites under par. (c) and applicable remedial design, operational and monitoring criteria under par. (d) will be met.

NR 140.28 Note Note: For most remedial actions, a microcosm or treatability study, or other bench scale or pilot scale study will be required by the department prior to consideration of an exemption for the full-scale remedial action under this section. If a pilot scale study is deemed necessary before an exemption for a full-scale remedial action can be granted, a separate temporary exemption issued under this section is required before the pilot scale study can begin.

NR 140.28(5)(c) (c) Exemption prerequisites. As part of the temporary exemption request, the owner or operator shall demonstrate to the satisfaction of the department that all of the following requirements will be met:

NR 140.28(5)(c)1. 1. The remedial action for restoring contaminated soil or groundwater, and any infiltrated or injected contaminated water and remedial material, shall achieve the applicable response objectives required by s. NR 140.24 (2) or 140.26 (2) within a reasonable period of time.

NR 140.28(5)(c)2. 2. The type, concentration and volume of substances or remedial material to be infiltrated or injected shall be minimized to the extent that is necessary for restoration of the contaminated soil or groundwater and be approved by the department prior to use.

NR 140.28(5)(c)3. 3. Any infiltration or injection of contaminated water or remedial material into soil or groundwater will not significantly increase the threat to public health or welfare.

NR 140.28(5)(c)4. 4. No uncontaminated or contaminated water, substance or remedial material will be infiltrated or injected into an area where a floating non-aqueous phase liquid is present in the contaminated soil or groundwater.