COMMENTS OF 3M COMPANY

Transcription

1 STATE OF MINNESOTA BEFORE THE OFFICE OF ADMINISTRATIVE HEARINGS Minnesota Department of Health Proposed Revisions to the Health Risk Limits Rules for Perfluorochemicals, Minnesota Rules, Parts , and COMMENTS OF 3M COMPANY August 8, 2007

2 TABLE OF CONTENTS EXECUTIVE SUMMARY... 2 A. Applicability of the HRLs... 2 B. The Legal Standard... 2 C. Due Process Requirements... 3 D. The MDH Calculations The Intake Rate for Drinking Water Relative Source Contribution The Reference Dose... 7 E. Other Peer-Reviewed Precedent... 8 F. Listing of Endpoints... 9 DISCUSSION... 9 I. MINNESOTA LAW REQUIRES THAT HRLS BE BASED ON THE GOVERNING LAW AND REGULATIONS AND CURRENT, SCIENTIFICALLY ACCEPTABLE, PEER REVIEWED INFORMATION... 9 II. THE PROPOSED HRLS CONTRAVENE THE STATUTORY MANDATE TO USE CURRENT, ACCEPTED, PEER-REVIEWED SCIENCE... 9 A. Intake Rate B. Relative Source Contribution C. Reference Dose Calculations Use of Erroneous PFOA Dose Level and Accompanying Uncertainty Factor Dose metric adjustment that is Inconsistent with Agency Policy and Published Literature III. THE UNITED KINGDOM S RECENT PROCESS ADDRESSING THE SAME DATA, USING THE SAME METHODOLOGY AND PEER REVIEW, PRODUCED SUBSTANTIALLY HIGHER PFOS AND PFOA VALUES i

3 IV. MDH S LISTING OF ENDPOINTS V. THERE IS NO HEALTH RISK FROM PFOS OR PFOA EXPOSURES IN MINNESOTA THAT WOULD JUSTIFY DEVIATION FROM STATUTORY AND REGULATORY REQUIREMENTS FOR ESTABLISHING HRLS CONCLUSION REFERENCES ATTACHMENT 1 ILLUSTRATION OF EXPOSURE LEVELS IN THE GENERAL POPULATION AND PERSONS EXPOSED VIA DRINKING WATER ATTACHMENT 2 RELATIVE SOURCE CONTRIBUTION BASED ON CURRENT EXPOSURE DATA AND PEER-REVIEWED LITERATURE A. MDH s Assumption is Contrary to Current Exposure Data B. MDH s assumption is contrary to EPA Guidance ATTACHMENT 3 MDH S UNFOUNDED USE OF A DOSE METRIC FACTOR BASED ON THE ASSUMPTION THAT ELIMINATION RATES GOVERN SERUM CONCENTRATION ATTACHMENT 4 MDH S LISTING OF ENDPOINTS A. PFOS and Lack of Thyroid Effects B. PFOA and Developmental Effects C. PFOA and Hematopoietic Effects D. PFOA and Immune Effects EXHIBITS ii

4 STATE OF MINNESOTA BEFORE THE OFFICE OF ADMINISTRATIVE HEARINGS Minnesota Department of Health Proposed Revisions to the Health Risk Limits Rules for Perfluorochemicals, Minnesota Rules, Parts , and COMMENTS OF 3M COMPANY 3M believes the Minnesota Department of Health (MDH) should establish Health Risk Limits (HRLs) for perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in accordance with Minnesota statutes and regulations. Although there is no health risk to the public at the levels of PFOS and PFOA found in the environment in Minnesota, it is important to provide benchmarks for addressing the levels found in the environment. Indeed, 3M has already addressed the presence of these substances in drinking water in Oakdale and Lake Elmo, 1 and has committed to remediating former disposal sites under a recent consent order with MPCA. 2 In fairness to the affected public, however, as well as to 3M and many potentially regulated parties beyond 3M, it is imperative that the proposed HRLs rest on a solid legal and scientific footing. In these comments, 3M explains why the HRLs as proposed do not do so. Rather, in several material respects, they depart from MDH s own rules for calculating HRL s and from more recently issued statutory requirements that require the use of currently available toxicity and exposure data and scientifically acceptable, peer-reviewed information. Accordingly, 3M respectfully requests that the Administrative Law Judge disapprove the proposed rules, and direct MDH to develop standards that comply with Minnesota law. A proposed order to this effect is attached at Exhibit M has already constructed a treatment system for affected municipal supply wells in Oakdale. The treatment system began operation on October 30, In Lake Elmo, PFOS and PFOA were not detected in municipal water, but were found in a number of private wells. 3M has committed over $5 million to fund a project extending municipal water to the affected areas. 2 3M has accepted responsibility for investigating and remediating the Oakdale disposal site, the Woodbury disposal site, and the Cottage Grove plant facility, and those efforts are well underway. 3M has also provided a grant to the State to support its work addressing the Washington County landfill, for which the State is legally responsible. See Settlement Agreement and Consent Order, available at or (PFOS and PFOA information page). 1

5 A. Applicability of the HRLs EXECUTIVE SUMMARY Despite the abbreviated process invoked in this proceeding, the proposed HRLs are regulations of general and broad applicability, with significant consequences. For instance, they will apply directly to all municipal water supplies in the State of Minnesota. In addition, the Minnesota Pollution Control Agency (MPCA) recently reported the presence of these substances in groundwater at a number of landfills around the state, unrelated to 3M. MPCA may utilize the HRLs as a basis for developing groundwater cleanup standards. MPCA may also use the MDH Reference Doses from the HRL calculations to derive discharge standards (e.g., for a number of municipal wastewater treatment plants that discharge PFOS or PFOA, see ) and standards for river, sediment, fish or soil concentrations that will apply to all persons in the state. Given the absence of EPA standards for PFOS and PFOA, and that Minnesota is the first state to adopt regulations addressing these substances in drinking water, it is imperative for the affected public and the regulated community (including municipalities and sites where MPCA has cleanup responsibility) that the HRLs be scientifically-based and comport with all legal requirements. B. The Legal Standard In March, 2007, the Legislature passed a law requiring MDH to develop and adopt HRLs for PFOA and PFOS: The commissioner shall develop and adopt the health risk limits according to Minnesota Statutes, section , and ensure that the health risk limits are based on currently available toxicity and exposure data. Minn. Laws ch. 37, 1. Thus, the proposed HRLs must meet two requirements: 1) they must be based on currently available toxicity and exposure data, and 2) they must also comply with Minn. Stat. sec , which requires that drinking water standards developed by the MDH must: (1) be based on scientifically acceptable, peer-reviewed information; and (2) include a reasonable margin of safety to adequately protect the health of infants, children and adults. (Emphasis added). Whether MDH has satisfied the substantive requirements of the statute in calculating the proposed HRLs is a question of law subject to de novo review by the ALJ. The standards applicable to the review of rules proposed for adoption under Minn. Stat. sec require 2

6 disapproval of the rule if it "exceeds, conflicts with, does not comply with, or grants the agency discretion beyond what is allowed by, its enabling statute or other applicable law;" or is illegal. Minn. R (D) and (E). C. Due Process Requirements Although Chapter 37 authorizes use of the good cause exemption to traditional rulemaking in this instance, even that abbreviated procedure anticipates minimal notions of due process, which MDH has failed to apply here. Specifically, MDH failed to include with its proposed rule any meaningful description of how it arrived at the methodology it used or the basis for the factors that it applied in that methodology, much less an explanation for why it departs from legally required methodology, or why it chooses not to apply scientifically acceptable, peer reviewed information. In effect, MDH has precluded the opportunity for meaningful comment by the public, and careful review by OAH, both of which are required by statute. To the extent that MDH asserts that Minn. Stat relieves it of any responsibility to explain the basis for its proposed HRLs or provide any details to support them, its application of the good cause exemption procedure precludes even the most minimal notice or a meaningful opportunity to be heard even under expedited conditions required by procedural due process protections. Likewise, this approach excludes from the ALJ's purview any careful examination of whether a rational basis for the agency's proposed decision exists, and leaves a reviewing court with no record on which a finding of a rational basis for the rule could be based. There are due process limits even to exempt rulemaking. When an agency fails to provide any explanation for its proposed action, it denies interested parties the statutory due process that the Minnesota Administrative Procedures Act was enacted to provide, see Minn. Stat , 3 and violates basic tenets of constitutional due process. Specifically, Minn. Stat grants to the courts: 3 Minn. Stat describes the over-arching purposes of the Administrative Procedures Act (APA), which includes: (1) to provide oversight of powers and duties delegated to administrative agencies; (2) to increase public accountability of administrative agencies; (3) to ensure a uniform minimum procedure; (4) to increase public access to governmental information; (5) to increase public participation in the formulation of administrative rules; (7) to simplify the process of judicial review of agency action as well as increase its ease and availability. The APA grants procedural rights with the expectation that better substantive results will be achieved in the everyday conduct of state government by improving the process by which those results are attained. Id. 3

7 [A]uthority to invalidate a rule if it violates a constitutional provision. Procedural due process guarantees notice and an opportunity to be heard. Minnesota Chamber of Commerce v. Minnesota Pollution Control Agency, 469 N.W.2d 100, 104 (Minn. App. 1991). In addition, substantive due process requires that the agency demonstrate a rational basis for its decision. As the Office of Administrative Hearings has noted, [t]he Minnesota Supreme Court has further defined an agency s burden in adopting rules by requiring it to explain on what evidence it is relying and how the evidence connects rationally with the agency s choice of action to be taken. In the Matter of the Proposed Amendments to Rules Relating to Valuation and Assessment of the Property of Utility Companies, Minnesota Rules, Chapter 8100, OAH Docket No , Report of the Administrative Law Judge (Feb. 16, 2007). 4 Any grant of such authority must be narrowly construed. 5 At most, Chapter 37 provides authority to derive HRL values for two specified chemicals, not to change the underlying methodology used to derive HRLs in Minnesota or to fail to use current data and published science to determine the inputs to the calculation of the HRLs. 4 While the MDH proposed rule that is currently before the ALJ in this proceeding must be evaluated de novo to determine whether it meets the requirements of Chapter 37, case law regarding the requirements of substantive due process in rulemaking are instructive, and were established in Manufactured Housing Inst. v. Pettersen, 347 N.W.2d 238, 244 (Minn. 1984). The court stated that in determining if the agency acted arbitrarily and capriciously the court must make a searching and careful inquiry of the record to ensure that the agency action has a rational basis. Further, the agency must explain on what evidence it is relying on and how that evidence connects rationally with the agency s choice of action to be taken. Id. Although governed by different statutory standards, in other contexts courts have held that an agency's failure to explain its reasoning is arbitrary and capricious. In re Whitehead, 399 N.W.2d 226, 229 (Minn. Ct. App. 1987); Five Star Trucking, Inc. v. Minnesota Transportation Regulation Board, 370 N.W.2d 666, 670 (Minn. Ct. App. 1985). An agency action is arbitrary and capricious if it relies on improper factors, fails to consider an important aspect of the problem, or offers an explanation that runs counter to the evidence. Citizens Advocating Responsible Dev. v. Kandiyohi County Bd. of Comm'rs, 713 N.W.2d 817, 832 (Minn.2006). 5 In interpreting Minnesota s good cause exemption, the Minnesota Court of Appeals has looked to federal law, which also contains a similar good cause exception. Id. at 608. Under federal law, the good cause exemption should be narrowly construed and only reluctantly countenanced. New Jersey Dept. of Environmental Protection v. United States Environmental Protection Agency, 626 F.2d 1038, 1045 (D.C. Cir. 1980). 4

8 D. The MDH Calculations The proposed HRLs deviate in a number of respects from current toxicity and exposure data and scientifically accepted, peer-reviewed literature, as required by statute. 3M will address each element of MDH s calculation in turn. It is difficult to do so, however, because MDH has provided no supporting documentation or explanation for its calculations. Despite having had several months to develop its proposals following enactment of the legislation directing their adoption by August 1, MDH has provided no Statement of Need and Reasonableness or other xplanation with the proposed regulations. However, because the numbers in the proposed regulations are the same as previous MDH guidance for PFOS and PFOA that had not been adopted by rulemaking, we can infer that the derivation of the proposed numbers is the same as set out in calculations supporting the previous guidance numbers. (MDH promulgated a number of HRLs in 1993 and 1994, but has relied on regulation by guidance document since then, establishing over 100 Health-Based Value or HBV guidance values for substances found in drinking water. PFOS and PFOA have been the subject of such guidance values without the benefit of notice and comment rulemaking as a result of MDH memoranda written in 2002 and 2007.) 3M therefore will look to two brief memoranda posted on MDH s web site calculating the 2007 Health-Based Value guidance numbers for PFOS and PFOA for explanation of the proposed HRLs. See (click in the box, where it says Health Risk Limits to pull up the HBV memoranda on the agency web site, even though the memoranda posted there are the guidance, not limits). For the ALJ s convenience, the PFOS HBV memorandum is attached as Exhibit 2 and the PFOA HBV memorandum is attached as Exhibit 3. However, the lack of explanation of the basis for the agency s proposed regulations raises due process concerns for interested parties who may wish to comment on the proposed rule. While the equations in the proposed regulation, and the calculations set out in the memoranda, are far from self-explanatory, we will address each step that goes into calculating a drinking water standard. 1. The Intake Rate for Drinking Water First, to establish the HRLs, MDH must assume an intake rate for how much drinking water a person consumes each day. This particular value is specified in MDH s implementing regulations promulgated in 1993 and has not changed since then. In this proposed rule, MDH departs from its own regulations and uses a different value for assumed drinking water intake to calculate the PFOS and PFOA HRLs. The regulations specify, in an equation spelled out in Minnesota Rules, part , subp. 2, that HRLs are to be calculated based on a 70 kilogram person (average lifetime weight) drinking 2 liters per day over the course of a lifetime. MDH has not used these values in the proposed HRLs. 5

9 Over the last several years, MDH has developed several drafts of potential revisions to the methodology used to calculate HRLs, and in particular, the intake rate. One draft of a proposed rule was subjected to an expert peer review and public comments from a number of outside experts, and MDH has subsequently withdrawn it and developed another draft proposal. Despite those efforts, however, the agency has yet to adopt, or even propose, changes in the HRL methodology. While the Legislature directed MDH to adopt HRLs for PFOS and PFOA using expedited procedures and current data, the enabling legislation did not authorize changes to the HRL methodology without notice and comment rulemaking. Nonetheless, in the proposed HRLs for PFOS and PFOA, MDH has used intake rates that depart from the rate specified in the agency s current regulations (and also departs from the initial and current drafts of the as-yet-unpromulgated methodology rule). The proposed intake rates therefore are not in accordance with law as required by Chapter 37. The proposed HRLs would nearly double if MDH used the required intake rate set forth in its adopted regulations. These are material changes. Although MDH has been directed to employ an expedited procedure, the agency cannot depart from the existing, legally binding regulations. The 2007 legislation did not authorize the use of ad hoc approaches to setting the PFOS and PFOA HRLs. 2. Relative Source Contribution To set an HRL, MDH must determine how much of the allowable daily intake of PFOS or PFOA can be allocated to drinking water, and how much must be reserved for exposures from other sources. This is the Relative Source Contribution, the source at issue here being drinking water. Here, it appears MDH has used a default assumption that contradicts current exposure data acknowledged by the agency. The proposed HRLs thus do not comport with the statutory mandate to employ current exposure data. Published literature studying a population in West Virginia and Ohio exposed to PFOA in drinking water shows that where there is drinking water exposure, it comprises the major source of exposure. (Emmett et al., 2006a and 2006b, attached as Exhibits 4 and 5. Published data for both Minneapolis/St. Paul and the U.S. population have thoroughly documented what background general population exposure is from other sources. (Olsen et al., 2003b, 2004a, 2004b, 2007b; Calafat et al., 2007.) Data in MDH s possession and EPA s public docket also show that the exposures for people living in Oakdale -- who were presumably exposed to PFOS and PFOA in drinking water prior to the implementation of treatment on the Oakdale municipal water system -- are due in very large part to the drinking water as opposed to background sources. MDH has publicly stated that dermal exposure is not likely and inhalation is not an important source of exposure. Accordingly, it is arbitrary for MDH to employ an assumption that only 20% of the daily dose can be allocated to drinking water where the Legislature has directed use of available exposure data. If MDH used even a conservative assumption of 60% for drinking water and 40% from other sources, the proposed HRLs would be increased by a factor of 3. 6

10 3. The Reference Dose In deriving HRL values, MDH sets a Reference Dose. The Reference Dose is the dose of a substance or chemical that is unlikely to cause toxic effects in humans who are exposed to this dose daily over a lifetime. Minnesota Rules, part , subp. 7. In other words, this level is the amount of the substance that the MDH deems acceptable for daily intake over the course of a lifetime. a. Selection of the Effect and Dose from the PFOA Animal Study In setting the Reference Dose, MDH departs from the legal requirements in several ways. First, MDH has misinterpreted the liver weight effects in the published PFOA study in selecting the study dose upon which to base the Reference Dose calculation, resulting in an incorrect Reference Dose. Second, MDH applies an unusual dose metric adjustment to the calculation that is not in accordance with the agency s own guidance and is based on inaccurate assumptions, as referenced in peer-reviewed literature. No adverse effects have been observed in humans as a result of exposure to PFOS and PFOA -- even at occupational exposure levels in 3M production workers that are hundreds or more times higher than levels in people previously exposed via drinking water in Minnesota. MDH therefore derives the Reference Dose using laboratory animal studies, in this case in monkeys. The agency first determines the level that causes no effect in the animal study, or the lowest level that causes an effect, and from that level, then applies safety factors (also called uncertainty factors) to account for uncertainty in animal to human extrapolation, to arrive at the Reference Dose. For PFOA, MDH states it has based the Reference Dose on the lowest dose in the study at which monkeys experienced increases in relative liver weight, which MDH says is the 3 mg/kg-day dose, and applies an uncertainty factor because that effect occurred even at the lowest doses in the study. The use of the 3 mg/kg-d dose level and accompanying uncertainty factor is incorrect, as reflected in the published study. There was a statistically significant effect on liver weight only at the high dose in the study and not at the lower doses of 3 or even 10 mg/kg-day. Even more significantly, absent other liver effects, changes in liver weight are adaptive responses by the animal to dosing, and not an adverse effect that represents or even leads to a disease. Peer-reviewed literature and EPA guidance make this clear. Thus, only at the highest dose in the study -- not the lowest dose used by MDH -- was there evidence to support an adverse effect on one monkey s liver. Quite simply, it appears that MDH s PFOA Reference Dose is overstated by a factor of ten, and thus does not reflect current toxicity data or scientifically acceptable, peer-reviewed information given that it misstates the effects in the published study. b. Application of A Dose Metric Adjustment for Extrapolation from PFOA and PFOS Monkey Data In setting the Reference Doses for both PFOS and PFOA, MDH has added an unusual dose metric adjustment to address the fact that PFOS and PFOA are eliminated more slowly 7

11 in humans than in monkeys. Such an adjustment factor is not typically used in risk assessment. In fact, 3M is unaware of the use of a comparable factor in any prior HRL or HBV calculation. There are three problems with this factor. First, the addition of an unusual dose metric adjustment to address animal to human extrapolation is comparable to the use of an additional factor for cross-species extrapolation. HRL calculations always use uncertainty factors to account for the uncertainty inherent in extrapolating across species. However, MDH, following EPA guidance, has said that it will not establish Reference Doses employing total factors greater than 3,000. In this case, the dose metric factors of 20 for PFOS and 70 for PFOA bring the total factors used to address cross-species extrapolation to 2,000 for PFOS and 21,000 for PFOA, respectively. (In other words, in the absence of health effects in humans, the allowable Reference Dose is set 2,000 or 21,000 times below the level at which effects occurred in monkeys in the laboratory studies.) This departs significantly from the agency s own established policy, and calls into question the agency s compliance with the statutory requirement to establish HRLs providing a reasonable margin of safety. Second, even assuming an adjustment for differences in elimination were appropriate, MDH uses values for the elimination of these chemicals in both monkeys and humans that are not based on current toxicity data, as required by law. Third, the premise underlying the dose metric adjustment is that the elimination rates in monkeys and humans predict the level of PFOS or PFOA that will accumulate in the blood, and therefore MDH must adjust for the different elimination rates in monkeys versus humans to protect humans from excessive exposure. However, peer-reviewed literature shows that the elimination rate is not the only or even primary factor that determines the accumulation of PFOS and PFOA in the body. MDH s use of a model based on elimination rates overstates actual blood serum concentrations by a factor of five to ten. Consequently, the dose metric adjustment is premised on what published literature demonstrates is an inaccurate model, and thus does not represent the use of currently available toxicology and exposure data and scientifically acceptable, peer-reviewed information, as required by law. E. Other Peer-Reviewed Precedent The proposed HRLs are inconsistent with the requirement of both chapter 37, 1, and the existing HRL regulations. MDH has a responsibility to the affected public to ensure that the proposed HRLs are scientifically supportable in accordance with the statutory requirements. To our knowledge, the only agency that has issued peer-reviewed Reference Doses for PFOS or PFOA, and drinking water values based upon them, is the United Kingdom. In June 2007, the U.K. issued drinking water levels for both PFOS and PFOA, following peer review of the science by a prestigious body of experts. The U.K. arrived at markedly different results from MDH s proposal, as described in detail in the discussion below. If the corrections 3M has noted here were applied to MDH s calculations, the resulting numbers would be much more in line 8

12 with the U.K. s values that are based on current, peer-reviewed toxicology. These values would still provide large margins of safety for the entire Minnesota population. F. Listing of Endpoints Finally, we must address one other element in the proposed regulation. The proposed language lists various endpoints as effects associated with PFOS and PFOA. MDH has provided no explanation of why these effects are selected, and several of them appear to be incorrect or misleading. This listing of endpoints has important ramifications in the way MDH applies the HRLs, because the list is used as the basis for an assumption that the effects of chemicals are additive to other chemicals that are listed for the same endpoints. See Minn. R Accordingly, we also address several of the proposed additivity endpoints that do not comport with scientifically accepted, peer-reviewed information as required by law. DISCUSSION I. MINNESOTA LAW REQUIRES THAT HRLS BE BASED ON THE GOVERNING LAW AND REGULATIONS AND CURRENT, SCIENTIFICALLY ACCEPTABLE, PEER REVIEWED INFORMATION The legislation under which MDH proposes the HRLs, 2007 Minn. Laws ch. 37, 1, requires MDH to develop and adopt HRLs, as defined in Minn. Stat. sec. 103H.005, subd. 3, for PFOA and PFOS: The commissioner shall develop and adopt the health risk limits according to Minnesota Statutes, section , and ensure that the health risk limits are based on currently available toxicity and exposure data. must: Minn. Stat. sec requires that drinking water standards developed by the MDH (1) be based on scientifically acceptable, peer-reviewed information; and (2) include a reasonable margin of safety to adequately protect the health of infants, children and adults. Despite the legislative mandate circumventing the normal notice and comment timeline, the HRLs must meet each of these legal requirements, and MDH must abide by its own regulations governing calculation of HRLs. II. THE PROPOSED HRLS CONTRAVENE THE STATUTORY MANDATE TO USE CURRENT, ACCEPTED, PEER-REVIEWED SCIENCE MDH has departed from its own regulations in setting the intake rate. It has ignored available exposure data and published literature in determining the Relative Source Contribution 9

13 of drinking water versus other pathways. And in determining the acceptable Reference Dose of PFOS and PFOA, it has made errors and assumptions contrary to published literature and its own established policy. These errors materially affect the proposed values. A. Intake Rate MDH promulgated rules implementing the HRL statute in 1993, at Minnesota Rules parts to Minnesota Rules, part , subp. 2, establishes the method for determining the HRLs in this case. The equation is: HRL = (RfD)(70)(RSC)(1,000) (2) The RfD is the Reference Dose, or the dose of a substance or chemical that is unlikely to cause toxic effects in humans who are exposed to this dose daily over a lifetime. (Minnesota Rules, part , subp. 7.) The numeral 70 is the standard weight of an adult expressed in kilograms. The RSC, or Relative Source Contribution, is the percent of total exposure to a substance or chemical, including air and food, that comes from ingesting water. The numeral 1,000 is a factor used to convert the units of concentration from milligrams per liter to micrograms per liter; and The numeral 2 is the standard amount of water ingested by an adult expressed in liters per day. In the 1993 rulemaking that adopted the currently effective method, and in an additional rulemaking in 1994, MDH adopted rules setting HRLs for 120 substances. 18 State Register 1340 (Nov. 15, 1993), 19 State Register 1191 (Nov. 28, 1994). Those HRLs remain in place. MDH has not adopted rules establishing new HRLs for any substance since that time, although it has adopted guidance on over 100 chemicals, including PFOS and PFOA, without the benefit of notice and comment rulemaking. MDH has never changed the methodology for calculating HRLs that it first set out in its initial HRL regulations. For the last several years, MDH has been developing a new approach to intake rates, rather than the 2 liters per day specified in the regulations, in response to the legislative directive to ensure reasonable margins of safety for adults, infants and children. The agency has issued several iterations of draft regulations. The agency has reviewed comments from a number of experts and solicited input from a peer review panel on the various drafts. 6 6 In December 2004, MDH circulated a draft Statement of Need and Reasonableness discussing potential proposed amendments to its health risk limits rule that would change the method used in the currently effective rule. Draft Statement of Need and Reasonableness, Proposed Amendment to Rules Governing Health Risk Limits for Groundwater, Minnesota Rules, et seq. (Dec. 15, 2004). Among other things, MDH proposed to amend the equation for developing health risk limits by adding various intake rate adjustments. MDH did not go forward with the proposed changes. Rather, prior to proposing a rule 10

14 MDH recently issued a revised draft of a potential revision to the HRL methodology that would revise the intake calculation. However, MDH has yet to propose or adopt any amendment to the method of calculation set forth in the current binding regulations. Against this backdrop, MDH has nevertheless used a different methodology to determine the proposed HRLs than what is specified in the current, binding regulations (or for that matter in any iteration of the unpromulgated draft methodology rule). MDH s current regulations prescribe that MDH will assume a daily intake of 2 liters of drinking water per day. The regulations also specify that MDH assume the water is consumed by a person with a lifetime average body weight of 70 kilograms. Minnesota Rules, part , subp. 2. These two factors mandated by the equation in the regulations translate to an intake rate of liters of water per kilogram of body weight per day. (2 liters divided by 70 kilograms = liters per kilogram). In the proposed HRL for PFOS,MDH improperly abandons the 2 liters per day and the 70 kilogram factors. Instead, for PFOS, MDH has used an intake rate of liters per kilogram of body weight per day -- about 1.6 times higher than provided in the equation called for in the regulations. For PFOA, MDH used an intake rate of about 1.8 times or almost double the intake rate specified in the regulation. 7 This reduces the HRLs. Although MDH has chosen to apply intake rate assumptions that have not been subject to any public notice and comment process, the provisions of Minn. Rules part , subp. 2, remain in effect. While the legislature gave MDH authority to abbreviate the normal rulemaking process to promulgate HRLs for PFOS and PFOA,that authorization did not extend to abandoning the rulemaking process for adoption of changes in the method for calculating HRLs. The directive from the legislature in Chapter 37 regarding adoption of HRLs for PFOS and PFOA did not repeal the equation adopted into Minnesota Rules as the methodology for calculating HRLs. change, MDH convened a peer review panel to review its draft, and, based in part on the peer review and public comments, as well as a review of new guidance from USEPA, MDH decided to withdraw draft HRLs it had calculated with a new methodology, as of April 12, MDH s web site now provides a description of different potential revisions to the regulations prescribing how HRLs will be calculated. MDH has not completed its redraft of the HRL methodology rule nor formally proposed it for adoption. 7 While it is not apparent from the proposed regulation, based on the memoranda describing the Health- Based Values guidance that preceded this proposal, we think MDH has purported to use average intake over a period of the first 27 years of life for PFOS and 19 years for PFOA. The selection of the time period other than the lifetime average specified in the regulation appears to be based on MDH s assumption that this is the amount of time needed to reach steady state serum concentrations for these chemicals. This assumption relies on the simple, one-compartment, first-order elimination model discussed below and in Attachment 3, which contradicts the published scientific literature. Thus, even if MDH had legal authority to deviate from the regulations, the scientific basis for the proposed values is nevertheless flawed. 11

15 Accordingly, the proposed HRLs are overstated, based on the legally-prescribed intake assumptions. MDH should be required to use the established methodology for making the computation. Use of any other methodology exceeds the authority granted under Chapter 37 and conflicts with the existing regulations, thereby requiring disapproval of the proposed rule under Minn. R (D) and (E). B. Relative Source Contribution MDH s current regulations state that the value for the Relative Source Contribution of drinking water to overall exposure is 0.2 (or 20%), unless data show that a higher value should be used. MDH has used a default value of 20% to represent the percentage of exposure to PFOA and PFOS that comes from drinking water as opposed to other sources. It has ignored current exposure data that indicate otherwise, which by law the agency must consider. Indeed, the legislative directive to consider current exposure date comes from the recent chapter 37 legislation, expressly directed at PFOS and PFOA. MDH assumes that 80% of exposure comes from sources other than water, and thus reserves 80% of the allowable daily dose of PFOS or PFOA for exposure from other sources. This has the effect of lowering the HRLs for PFOA and PFOS in drinking water. Assignment of a greater fraction of exposure to drinking water would increase the proposed HRLs. Data on exposures are available from 1) a peer-reviewed University of Pennsylvania study of a community exposed to PFOA in drinking water in West Virginia, and 2) current exposure data on persons living in Oakdale and presumably exposed to PFOA and PFOS in municipal water prior to the installation of treatment. In addition, background exposures in the general population have been well characterized in a number of 3M and U.S. Centers for Disease Control publications. Multiple published studies of Red Cross donors in the Minneapolis/St. Paul region are available and can be used to represent the Minnesota general population data. By comparing exposures in persons with and without known drinking water exposure, the contribution of the drinking water exposure is readily apparent. As shown on the table in Attachment 2, which provides more detail, available data show that the portion of exposure attributable to drinking water in cases where there is a source of PFOS or PFOA in drinking water is closer to 94% of overall exposure for PFOA and 73% for PFOS. If MDH were to use even 60% as a cautious approach, this would increase the proposed HRLs by a factor of 3. If MDH assumed 80% comes from drinking water and 20% from other background sources, the HRLs would increase by a factor of 4. During a public presentation given on May 30 th, 2007, Mr. Larry Gust of MDH stated that the major exposure source was drinking water. His slides indicated that dermal exposure is not likely, and inhalation exposure is not important. See Public Health Policy and Actions Taken in Communities, available at MDH s use of the 20% default assumption is therefore inconsistent with its own understanding of relative 12

16 source contributions and contrary to the Legislature s specific directive to MDH to use current exposure data. It is also contrary to the EPA guidance that MDH purports to follow, as described more fully in Attachment 1. MDH has asserted in correspondence to 3M that EPA s guidance supports use of the default factor, but it appears that application of the EPA guidance would lead to a Relative Source Contribution of 50-80% based on data rather than 20% based on a default assumption. C. Reference Dose Calculations The proposed HRLs are predicated on MDH s Reference Doses, representing the acceptable level of PFOS or PFOA consumed on a daily basis over a lifetime. MDH would typically rely on EPA to provide Reference Doses. In fact, MDH initially interpreted the HRL statute to require the use of EPA data for the Reference Dose. See the Statement of Need and Reasonableness, In the Matter of Proposed Rules of the Minnesota Department of Health Relating to Health Risk Limits, Minnesota Rules, Parts to (March 12, 1994), at In the 2004/2005 Draft SONAR, at 31-34, described above in connection with MDH s as-yet unpromulgated revisions to the HRL methodology, MDH proposed to modify its interpretation of the HRL statute to permit the use of non-epa Reference Doses. As there are no EPA Reference Doses for PFOS and PFOA, MDH has derived its own Reference Doses. In the proposed rule, MDH lists the Reference Doses ( mg/kg-d for PFOS and mg/kg-d for PFOA) in a table in Section The origin of the Reference Doses is not explained anywhere in the proposed regulation, but the derivation of the numbers shown in the proposed regulation parallels the numbers documented in the HBV guidance memoranda posted on MDH s web site and attached here as Exhibits 2 (PFOS) and 3 (PFOA). 3M will assume the Reference Doses in the proposed regulations were arrived at using the calculations set out in the HBV memoranda that arrive at the same numbers. 3M agrees with MDH s use of the monkey studies on PFOS and PFOA as the basis for deriving the Reference Doses, given the absence of effects in humans. See the attached letter from Dr. Butenhoff to Dr. Goeden of MDH, July 2, 2007, Exhibit 6. However, the MDH Reference Dose calculation for PFOA appears to be based on a misinterpretation of the relevant dose level in the published monkey study, and hence it does not comply with the mandate to use scientifically acceptable peer-reviewed information. Moreover, the effect selected for use in the Reference Dose is not one that would be used under peerreviewed EPA guidance or current toxicological evidence. In addition, the Reference Doses for PFOA and PFOS both include an adjustment factor for extrapolating from monkeys to humans that is contrary to current toxicological evidence and published peer-reviewed literature. 13

17 1. Use of Erroneous PFOA Dose Level and Accompanying Uncertainty Factor A laboratory toxicology study typically exposes animals to several dose levels of a substance, and compares the effects in the exposed animals to unexposed animals (or controls). Such studies are designed to elicit effects at the higher doses, and also to have a low enough dose to show the level at which there are no effects in the animals. To establish a Reference Dose, an agency would typically use the dose level in the animal study at which adverse effects did not occur (the no observed adverse effect level or NOAEL). The agency would then apply safety factors (called uncertainty factors) to protect humans given that the calculation must extrapolate from animal studies. If there is not a no-effect level, i.e., there are adverse effects observed at every dose in the laboratory animal study, then it is customary to use the lowest dose, called the lowest observed adverse effect level (LOAEL), and to apply an additional uncertainty factor, to set the dose that is acceptable for humans. In setting the HBV Reference Dose, MDH uses increased relative liver weight as the critical effect in the PFOA monkey study on which the Reference Dose is based. However, MDH has incorrectly identified the dose at which increased liver weight relative to body weight occurred. MDH states that the study s low dose (3 mg/kg-d) is the LOAEL for increased relative liver weight. MDH then adds an uncertainty factor of 3 to account for going from a LOAEL to a NOAEL (resulting in a level of 1 mg/kg-d).. In fact, increased relative liver weight occurred only at the highest dose in the study. This makes the 10 mg/kg-d dose level an NOAEL, and no additional uncertainty factor is needed. 8 This alters the proposed HRL by a factor of 10. Moreover, even if relative liver weight had been increased at the low dose used by MDH, scientifically accepted, peer-reviewed information and EPA guidance indicate that this effect alone should not be used as the basis for a Reference Dose because it is not an adverse effect. Increased liver weight without clinical or histological evidence of pathology is considered adaptive and benign, not adverse (Amacher et al., 2006). Indeed, the Toxicology Science Advisory Council for EPA s Office of Pesticide Programs in 2002 produced a guidance document addressing the use of liver weight in setting Reference Doses. 9 This guidance states that liver size or weight changes may be indicative of adaptation which, by itself, is not necessarily adverse. Absent microscopic evidence of liver injury or change, at least two liverrelated clinical chemistry parameters should be significantly elevated before liver weight changes are ascribed to toxicity. The EPA guidance specifically defines the NOAEL as a dose which elicits either no response or only adaptive, non-adverse responses (e.g., hepatocellular hypertrophy [liver weight changes] alone). The LOAEL is defined as a dose which elicits adverse effects (e.g., hepatocellular hypertrophy in addition to other evidence of liver toxicity). 8 Although absolute liver weight and liver weight relative to brain weight were statistically significantly increased at all doses, relative liver weight was only increased at the highest dose in the study. There was no statistically significant effect on relative liver weight at the 3 or 10 mg/kg-d dose levels. See page 253 of Exhibit 7, Butenhoff, et al., 2002, at Table 6. 9 Hepatocellular Hypertrophy. Health Effects Division Guidance Document # G , October 21, 2002, US EPA. Hepatocellular hypertrophy, or enlarged liver cells, results in increased liver weight. 14

18 This peer-reviewed EPA guidance reflects scientifically acceptable information, as is required under Minnesota statute to support HRLs. Accordingly, MDH should not treat relative liver weight increases as an adverse effect if additional clinical and histological evidence of liver toxicity are lacking. There were no indications of liver toxicity in either the clinical chemistry or the histopathology at both lower doses in the study (3 and 10 mg/kg-d). One monkey at the highest study dose (30/20 mg/kg-d) did have indications of liver toxicity. Thus, based on scientifically accepted EPA guidance, 10 mg/kg-d should be a study NOAEL for liver effects. 10 The Reference Dose for PFOA used in the HRL based on liver effects is overstated by a factor of 10. MDH is obligated to promulgate a Reference Dose that comports with the findings in the published peer-reviewed study, with current toxicology, and with scientifically acceptable, peerreviewed information. We submit that MDH s PFOA Reference Dose is in fact based on the wrong dose, and should not have been used to calculate the HRL. 2. Dose metric adjustment that is inconsistent with agency policy and published literature 3M also takes issue with the unusual dose metric adjustment to correct for the half-life difference between humans and monkeys that is part of MDH s calculation of the Reference Dose. This factor is not evident in the text of the proposed HRLs. Rather, it is embedded in the derivation of the HBV Reference Dose explained in Exhibits 2 (PFOS) and 3 (PFOA), which we presume applies with respect to the proposed HRLs. The use of this factor is inconsistent with stated MDH policy with respect to safety factors, and MDH s scientific basis for the use of the adjustment factor is inaccurate, based on information presented in multiple peer-reviewed publications. The half life of a substance is the amount of time it takes for half of the substance to be eliminated from the body. Because the half-life of PFOS and PFOA in humans is longer than the half-life in monkeys, MDH adds an unusual correction factor to the derivation of the Reference Dose. MDH takes a ratio of the human half life to the monkey half life, and reduces the Reference Dose by this factor: a factor of 20 in the case of PFOS and 70 in the case of PFOA. This unusual adjustment results in a material change -- it affects the proposed HRLs in the amount of those factors. MDH s dose metric adjustment is actually another factor to address inter-species extrapolation. For PFOS, MDH has applied uncertainty factors of 3 and 10 to account for interspecies extrapolation, and a factor of 3 for use of a LOAEL rather than NOAEL, which MDH rounds after multiplying them to a total uncertainty factor of 100 for 10 Although one low dose monkey was sacrificed in extremis, a thorough pathology review deemed the death unlikely to be related to the dosing with PFOA. MDH s memorandum memorializing its derivation of the Reference Dose does not purport to rely on this as the basis of the Reference Dose. 15

19 extrapolation from the monkey study. The additional dose metric factor for extrapolating from monkey data to humans adds a factor of 20, which is also multiplicative. Thus, the total uncertainty factor is 2,000. In other words, the margin of safety between the dose causing effects in monkeys exposed to PFOS and the allowable Reference Dose for humans is 2,000 under the proposed HRL. For PFOA, MDH has used an uncertainty factor of 100 for cross-species extrapolation and other potential variability, multiplied by the factor of 3 for use of a LOAEL rather than a NOAEL, multiplied by the additional factor of 70 for the supposed monkey-human dose metric adjustment -- for a total margin of 21,000 reflected in the PFOA Reference Dose compared to the level producing effects in monkeys. MDH states in the 2004/2005 draft SONAR (pages 4, 26) that if a chemical s uncertainty factor is over 3000, there is insufficient information to promulgate an HRL. MDH there references an EPA report on Reference Doses which recommended limiting uncertainty factors to no more than In keeping with this recommendation and the rationale supporting it, the MDH has not developed an HRL for any chemical if total factors would exceed /2005 SONAR at p. 26. MDH here appears to depart from established precedent in its proposed HRL for PFOA. Moreover, the dose metric adjustment factors to address the uncertainty arising from the differences between monkeys and humans do not comport with the published literature. First, the actual numbers used to calculate the half-life ratios used for the adjustment are incorrect. Second, the basis for the half-life adjustment appears to be MDH s assumption that it is the halflife of elimination that determines the levels at which serum concentrations accumulate and plateau. Published literature has shown that the elimination rate alone does not determine the extent of accumulation. On the first point regarding the mathematical half-life ratios, MDH has not used the correct monkey and human half-life data available in the scientific literature. 11 Thus, where MDH used a ratio of 70 to reflect the difference in serum elimination half-life between humans and monkeys for PFOA, the actual value should be approximately 50, if in fact serum concentrations depend on half-life. Where MDH used a ratio of 20 to reflect the difference in 11 MDH used human half-lives of 3.8 years for PFOA and 5.4 years for PFOS. Because serum concentrations in the human population are well-recognized to be distributed in a log-normal manner, it is also likely that the half life is log normal, as can be seen in Olsen et al., 2007a. Therefore, MDH should have used the geometric mean human half-life of 3.5 years (1278 days) for PFOA or 4.8 years (1753 days) for PFOS. Id. For the monkey, MDH uses a value of 20 days for the half-life of PFOA in male monkeys. However, a formal pharmacokinetic study of three male and three female monkeys produced a mean half-life of 26.7 days. Butenhoff et al., 2004c (calculated combining males and females). The same study showed a halflife of 120 days for PFOS in male and female monkeys, as opposed to the 98.6 days MDH appears to have used. 16