June 15, 1999
The Honorable Charles Chvala
Senate Organization Committee
211 South, State Capitol
Madison, WI 53702
Dear Senator Chvala:
You have asked for a formal opinion on whether the promulgation of rules that prescribe the use of risk-based methodologies, such as the American Society for Testing and Materials’ Risk-Based Corrective Action, to respond to petroleum contamination under Wisconsin’s Petroleum Environmental Cleanup Fund, would be consistent with the provisions in Wis. Stat. ch. 160 (“chapter 160”). Petroleum contamination can affect both soil and groundwater, and the Petroleum Environmental Cleanup Fund provides a mechanism for funding the remediation of petroleum contamination wherever it occurs. Chapter 160 is known as Wisconsin’s groundwater law and sets forth the standards for the remediation of contaminated groundwater. Your question is whether rules incorporating Risk-Based Corrective Action would provide for the remediation of petroleum contamination in groundwater consistent with the groundwater standards prescribed in chapter 160. It is my opinion that certain core components of Risk-Based Corrective Action are not consistent with chapter 160.
I will first provide a brief overview of the regulatory framework relating to petroleum contamination, as background for those unfamiliar with that framework and the Petroleum Environmental Cleanup Fund program. Petroleum is a hazardous substance, and Wisconsin’s hazardous substance spills law requires that certain persons remediate the contamination resulting from the discharge of a hazardous substance. These persons include those who cause the discharge, own or control the substance that is discharged, or own or control the contaminated property. Wis. Stat. §§ 292.01(5) and 292.11(3). These general provisions provide the authority to require cleanup of petroleum contamination from leaking underground petroleum storage tanks. Federal law imposes additional mandates applicable to discharges from underground storage tanks. See 40 C.F.R. §§ 280.40-280.67 and 40 C.F.R. ch. 281 (1998). Pursuant to these state and federal laws, the Department of Natural Resources and Department of Commerce have promulgated rules specific to discharges from underground storage tanks. See Wis. Admin. Code §§ NR 706.11-706.17, and Wis. Admin. Code ch. Comm 47.
Petroleum contamination from older underground storage tanks is a national problem. In response to this problem, federal law requires that underground storage tank owners upgrade or close existing underground storage tanks, and obtain $500,000, $1 million or $2 million (depending on location and number of tanks) in insurance to be used to address contamination caused by leaks from the tanks. 40 C.F.R. §§ 280.93-280.116 and 281.37 (1998). Most states have established cleanup assistance funds to enable owners to meet this insurance mandate. The Wisconsin fund is called the Petroleum Environmental Cleanup Fund (“PECFA”), and reimburses owners that clean up soil and groundwater contamination from petroleum storage tanks. See Wis. Stat. §§ 101.143-101.144.
The Department of Commerce administers PECFA. The Department of Commerce is responsible for the financial management of PECFA and the processing of PECFA reimbursement claims. The Department of Commerce also oversees the remediation of lower priority sites, which are typically sites that involve soil contamination only or groundwater contamination below state groundwater standards. The Department of Natural Resources oversees the remediation of higher priority sites, where groundwater contamination exceeds state standards, and sets the clean-up standards and procedures for all sites. See Wis. Stat. §§ 101.143-101.144.
PECFA is funded by a $0.03 per gallon inspection fee assessed on petroleum products imported into the state by wholesalers. Wis. Stat. §§ 20.143(3)(v), 25.47 and 168.12. Reimbursement claims have greatly exceeded the revenue from that fee. In response to the growing gap between PECFA revenue and costs, the legislature directed the Department of Commerce and the Department of Natural Resources to promulgate rules to implement cost controls and to facilitate less expensive and quicker remediation of sites. In response to that directive, the departments considered adopting by rule the risk-based approach to remediation of petroleum contamination known as the American Society for Testing and Materials’ Risk-Based Corrective Action. The question arose whether that approach would allow sites to be closed with contamination above the groundwater standards in chapter 160, in violation of chapter 160. As discussed below, it is my opinion that the answer is yes.
The American Society for Testing and Materials’ Risk-Based Corrective Action is known as “RBCA” and is described in detail in the American Society for Testing and Materials’ “E1739-95e1 Standard Guide for Risk-Based Corrective Action Applied at Petroleum Release Sites (1995) (“ASTM Standard Guide”). The general difference between RBCA and chapter 160 is that RBCA directs remediation efforts based on the risk of human exposure, while chapter 160 requires remediation of all sites to meet the numeric groundwater standards prescribed in that chapter. Because chapter 160 requires the state to protect all groundwater, regardless of the risk of human exposure, chapter 160 imposes a more stringent remediation standard for sites with groundwater contamination than RBCA.
Many components of RBCA, notably the risk-based assessment and cost-saving objectives, are expressly authorized by chapter 160. These components are also already incorporated in the regulations in chapter NR 700 of the Wisconsin Administrative Code (“NR 700”), which address the investigation and remediation of any kind of environmental pollution, in both soil and groundwater, consistent with chapter 160. The range of remediation responses authorized by chapter 160 and Wisconsin Administrative Code ch. NR 726 includes the range of responses possible under RBCA. However, it is shown below that certain key elements of RBCA violate both the letter and intent of chapter 160. In particular, RBCA calls for the development of groundwater standards other than, and less protective than, the numerical standards prescribed by chapter 160. In addition, RBCA’s unconditional allowance of continued contamination above those numerical standards, both on the property where the contamination originated and on neighboring properties to which the contamination has spread, is also inconsistent with chapter 160.
The critical conflicts between chapter 160 and RBCA arise in three areas. The first area is the scope of the investigation of and response to contamination, and involves where contamination must be measured. The second area of conflict concerns the level of protection, or what standards must be met in remediating the contamination. The third area relates to the degree of assurance that the remediation is effective, and involves when a site may be closed and no further remedial action is required. In order to show the sources of these conflicts, I begin with an overview of chapter 160 and certain of the rules implementing its mandates, continue with an overview of RBCA, and conclude with a comparison of the two regulatory schemes.
Chapter 160 was developed to meet the need to maintain groundwater resources “at some level of quality for both consumptive and non-consumptive uses.” Wisconsin Legislative Council Memorandum No. 2, Identification of the Problems in Protecting Wisconsin’s Groundwater Resources, May 24, 1982, to Members of the Special Committee on Groundwater Management, at 1. Chapter 160 establishes a process for the protection of the state’s groundwater resources based on quantitative standards, called numerical standards in the statute. Wis. Stat. § 160.001. These numerical standards are to be developed and used to minimize the concentration of polluting substances in groundwater. Wis. Stat. § 160.001(1). These numerical standards must be used and achieved by all groundwater programs. Wis. Stat. § 160.001 (intro.), (1), (3) and (4). Regulations that provide greater protection than the statutory numerical standards are also allowed. Wis. Stat. § 160.001(5)-(6). Both the Department of Commerce and the Department of Natural Resources are subject to the requirements of, and standards set by, chapter 160. Wis. Stat. §§ 160.001(3)-(7) and 160.01(7).
The statute creates two types of numerical standards: enforcement standards and preventive action limits. Wis. Stat. § 160.001(1). Enforcement standards are derived primarily from federal or state drinking water standards. Wis. Stat. §§ 160.01(2)-(3) and 160.07-160.13. Generally, a regulatory agency may not allow a facility or activity to violate enforcement standards, and must require that contaminated sites be remediated so as to meet enforcement standards. Wis. Stat §§ 160.19. 160.21 and 160.25. Preventive action limits are a certain percentage of the enforcement standards. Wis. Stat. § 160.15. Preventive action limits act as a trigger for remedial action, and are to be met if technically and economically feasible. Wis. Stat. §§ 160.001(8), 160.19, 160.21 and 160.23.
The Department of Natural Resources must set these numerical standards for substances that are in or likely to enter the groundwater resources of the state, and which affect public health or welfare. Wis. Stat. §§ 160.05(1) and (6), 160.07, 160.09 and 160.15. In identifying substances that affect public health, the department must consider a substance’s effect on mortality, illness, and other aspects of human health. Wis. Stat. § 160.05(6)(b)-(c). In identifying substances that affect public welfare, the department must consider a substance’s effect on the water’s suitability for human use and for uses other than drinking water, and on plants and animals. Wis. Stat. § 160.05(6)(d)1.-3. Any other characteristics of a substance connected to public welfare may also be considered. Wis. Stat. § 160.05(6)(e). Chapter NR 140 of the Wisconsin Administrative Code identifies the substances and their numerical standards as required by chapter 160.
The places where contamination must be measured to determine whether the numerical standards mandated by chapter 160 are met are called “points of standards application.” Wis. Stat. § 160.01(5). These points are determined based on whether monitoring is required. Wis. Stat. § 160.21. If monitoring is required, the points of standards application (where contamination must be measured) are wherever the monitoring is being done, wherever groundwater is being used, and on other properties where the contamination has spread. Wis. Stat. § 160.21(2)(a)1.-2. If monitoring is not required, the only difference is that no measurements need be taken at points of nonpotable groundwater use. Wis. Stat. § 160.21(2)(b)1.a. The department may by rule establish points of standards application, or measurement, at additional points to those identified above, to protect future groundwater uses and the public interest in state waters. Wis. Stat. § 160.21(2)(b)2.
The Department of Natural Resources is required to mandate monitoring in certain situations. Wis. Stat. § 160.27. Monitoring is required at contaminated sites, both to determine whether enforcement standards or preventive action limits are violated, and to determine the appropriate response to any such violations. Wis. Stat. § 160.27(2)(a)-(b). Accordingly, monitoring is required at all sites involved with PECFA because those sites are contaminated with petroleum from leaking underground storage tanks. Because monitoring is required at PECFA sites, continued violation of preventive action limits is prohibited wherever groundwater is monitored on those sites, unless compliance is not technically or economically feasible. Wis. Stat. §§ 160.21(2)(a)1. and 160.23(1)(b). Because monitoring is required at PECFA sites, enforcement standards may never be allowed to continue to be violated at any point of present groundwater use, or beyond the property lines off-site. Wis. Stat. §§ 160.21(2)(a)2. and 160.23(1)(c).
Where a preventive action limit or enforcement standard is attained or exceeded, the response may vary depending on many factors, including risk and cost effectiveness. Wis. Stat. § 160.21(3) and (4). However, whatever response is chosen must ensure compliance with enforcement standards at all points of standards application. Wis. Stat. §§ 160.23(1)(c) and 160.25(1) and (2). For PECFA sites, as noted above, those points are, at a minimum, at any point of groundwater use and any point off-site. In addition, the preventive action limits should be met unless technically or economically infeasible. Wis. Stat. § 160.23(1)(b).
Chapter 160 authorizes state agencies to promulgate regulations consistent with the requirements set forth above. Wis. Stat. § 160.19(1). The Department of Natural Resources has since 1974 adopted a series of regulations in chapters NR 700-750 of the Wisconsin Administrative Code to address contamination by hazardous substances generally. The proposed RBCA regulations would provide a separate regimen for responding to sites containing petroleum contamination.
Both sets of regulations aim to provide for more flexible and less costly clean-ups. Many of the points at which the NR 700 rules and RBCA diverge are merely variants of similar processes based on similar factors. Other points of divergence are where RBCA is not consistent with chapter 160. The basis for these inconsistencies is that while the NR 700 rules incorporate chapter 160 standards, RBCA does not.
The NR 700 series of regulations was adopted to address the identification, investigation and remediation of contaminated sites, in a consistent but flexible and cost-effective, even cost-saving, way. Wis. Admin. Code § NR 700.01(2); Adoption of Order SW-12-96, Memorandum to Natural Resources Board Members, June 12, 1996, at 13 (Response to Comment 4); Authorization for Hearing, January 11, 1996. Under these comprehensive environmental clean-up rules, contaminated sites are prioritized (Wis. Admin. Code ch. NR 710), investigated so as to determine the full extent of violations of soil and groundwater standards (Wis. Admin. Code ch. NR 716), remediated in a technically feasible and cost-effective way (Wis. Admin. Code ch. NR 722), monitored based on actual site measurements (Wis. Admin. Code ch. NR 724), and closed upon compliance with soil and groundwater standards (Wis. Admin. Code ch. NR 726).
The NR 700 regulations prescribe a process for remediating contamination at almost any site, with the response determined in part on coming into compliance with chapter 160 groundwater standards. The NR 700 regulations allow closure of a site where chapter 160 groundwater enforcement standards have not been met, only if: 1) adequate source control measures have been implemented (for example, enough work has been done to control a groundwater plume so as to prevent additional contamination in violation of groundwater standards), 2) natural attenuation is, and is shown to be, reducing the contamination so as to attain groundwater standards in a reasonable period of time, 3) there is no off-site violation of groundwater preventive action limits, and 4) a groundwater use restriction is placed on the property deed. Wis. Admin. Code § NR 726.05.
RBCA is a process for addressing contamination only at petroleum-contaminated sites, with remediation dependent on exposure and determined by margins of safety. As with the NR 700 rules, the RBCA process progresses from prioritizing a contaminated site, to investigation (called evaluation under RBCA), remediation and closure. However, the scope of the investigation and appropriate response, the level of remediation, and the standards for closure under RBCA differ substantively from the NR 700 rules, and these differences are precisely the points where RBCA is not consistent with chapter 160.
The first set of inconsistencies involves the scope of the investigation and response required by the regulations. To ensure compliance with chapter 160’s groundwater standards, NR 700 requires a site investigation sufficient to determine the full extent of the contamination. Wis. Admin. Code ch. NR 716. In contrast, RBCA calls for a site to be evaluated primarily to identify the sources of the contamination, any people, structures, utilities, surface waters or drinking wells adversely affected by the contamination (called “receptors”), and pathways of certain chemicals. ASTM Standard Guide §§ 3.1.29 and 6.6. If there are no receptors on or near a property, the extent of the contamination need not be determined under RBCA, with the result that contamination at or above the groundwater standards prescribed in chapter 160 may be left unaddressed. ASTM Standard Guide § 6.6.2 and 6.6.4.
A key difference between RBCA and chapter 160 (and the NR 700 regulations) involves where measurements must be taken. As explained above, chapter 160 requires measurements of contamination to determine compliance with preventive action limits wherever groundwater is monitored, and compliance with enforcement standards at any point of groundwater use and off-site. As explained below, RBCA requires measurements only onsite and only if there are points of human contact. If there are no points of human contact, no measurement is required, and so there is no contamination to which to respond. If there are points of human contact, measurements are taken only on-site.
RBCA’s measurement points, called points of compliance, do not match chapter 160’s measurement points, called points of standards application, and in fact limit measurement of contamination. Measurements for response and closure under RBCA are taken at points of compliance, which are points between source areas (where chemical concentrations are highest) and potential points of exposure. ASTM Standard Guide §§ 3.1.23, 6.7, 6.10, 6.12 and 6.13. Points of exposure are points of human contact with a chemical (such as a drinking well). ASTM Standard Guide § 3.1.24. If there are no points of human contact on a site, then there are no measurements to be made and no basis for remediation. ASTM Standard Guide §§ 3.1.23, 3.1.24 and 6.7.1.
If points of human contact do exist at a site, points of compliance must be selected for measurement. Because points of compliance must be between the points of human contact and source areas, and source areas are most likely to be onsite (hence use of the term source), only onsite points need to be selected for measurement. When screening or site-specific levels are met at those points, no additional response is necessary and the site is closed. ASTM Standard Guide §§ 188.8.131.52 and 6.7.3. No response at all is necessary if no receptors (people, structures, utilities, surface waters or drinking wells adversely affected by contamination) exist. ASTM Standard Guide §§ 3.1.29, 6.6.2 and 6.6.4.
The result of the differences between points of compliance and points of standards application is that contamination caught under chapter 160 may never be caught, or may be inadequately defined and therefore responded to, under RBCA rules, in violation of chapter 160 standards. For example, chapter 160 requires action if a plume is expanding so as to exceed groundwater standards. RBCA requires no response at all if there are no receptors or points of human contact, even if contamination is spreading. And RBCA requires no measurement of, and therefore no response to, contamination off-site. Consequently, violations of enforcement standards, which chapter 160 prohibits, may under RBCA be allowed to remain, and even to get worse, off-site. Violations of enforcement standards may also be allowed to remain on-site if there are no receptors or points of human contact.
The second set of inconsistencies involves the standards that dictate when action must be taken and when compliance is achieved. These standards define the different levels of protection provided under chapter 160 and RBCA. Chapter 160 mandates only two numerical groundwater standards: preventive action limits and enforcement standards. These standards are uniform throughout the state, based primarily on federal or state drinking water standards.
RBCA calls for the development of other numerical standards not authorized by chapter 160. The basic RBCA standards are risk-based screening levels, which are derived for standard exposure scenarios, such as residential or commercial use of the property. ASTM Standard Guide §§ 6.4-6.7. RBCA provides the option of developing site-specific target levels that are also related to exposure. ASTM Standard Guide §§6.8-6.9. RBCA’s risk-based screening levels and site-specific target levels are specific to a site or class of sites, based on exposure at that site or within that class. There is no authority under chapter 160 to generate RBCA’s table of screening levels or to develop RBCA’s site-specific target levels, both of which are different from chapter 160 preventive action limits and enforcement standards.
These differences in standards and measurement points result in inconsistencies in the degree of assurance prescribed by chapter 160 and provided under RBCA. Chapter 160 does not allow a site to be closed without its coming (or its being shown to be coming) into compliance with enforcement standards (and also with preventive action limits if technically and economically feasible). Contrary to this statutory mandate, RBCA unconditionally allows violations of both standards to persist—on-site if there are no receptors or human exposure, and off-site if off-site contamination is not measured.
These inconsistencies between chapter 160 and RBCA stem from their different orientations. Chapter 160 requires regulatory oversight for the sake of the groundwater (see Wis. Stat. § 160.001), whereas RBCA requires regulatory oversight for the sake of who is at risk (see ATSM Standard Guide, § 1.1). Chapter 160 expressly requires the clean-up process to be based on a property’s coming into compliance with the chapter’s numerical standards. RBCA conditions the clean-up process on exposure and margins of safety, based on a limited view of the source of risk.
It is my opinion that neither the scope, nor the standards, nor the degree of assurance defined by RBCA are consistent with chapter 160. RBCA limits the measurement of contamination so that a response sufficient to meet chapter 160 standards is not ensured. RBCA bases corrective action on standards other than the numerical groundwater standards—enforcement standards and preventive action limits—mandated by chapter 160. Finally, RBCA allows the level of contamination at a site to remain in violation of those statutory groundwater standards. In these ways, RBCA is not consistent with chapter 160.
James E. Doyle
The promulgation of rules that prescribe the use of risk-based methodologies, such as the American Society for Testing and Materials' Risk-Based Corrective Action, to respond to petroleum contamination in soil and groundwater, would violate Wis. Stat. ch. 160. The risk-based program limits the measurement of contamination so that a response sufficient to meet chapter 160 groundwater standards is not ensured, bases corrective action on standards other than the groundwater standards mandated by chapter 160, and allows the level of contamination at a site to remain in violation of those statutory groundwater standards.