Opinion ID: 185864
Heading Depth: 1
Heading Rank: 6

Heading: THE MERITS OF THE URANIUM MCLs

Text: 82 Petitioners also challenge EPA's determination of both the MCLG at 0 µg/L and the M.C.L. at 30 µg/L for uranium on the merits of the science used by EPA. They make three challenges to the MCLG and assert that EPA's reliance on an improper MCLG tainted its M.C.L. determination, as did EPA's reliance on kidney toxicity data. Regarding the MCLG, petitioners contend that (1) the best available peer-reviewed science, 42 U.S.C. § 300g-1(b)(3)(A)(i), does not support a 0 µg/L MCLG because the LNT model used by EPA is not supported by the science; (2) under EPA's classification system for carcinogens, a 0 µg/L MCLG is inappropriate; and (3) EPA ignored a report by the Agency for Toxic Substances and Disease Registry (ATSDR) on the toxicity of uranium. Finally, petitioners also argue that EPA's cost-benefit decision, which determined the final level for the MCL, was substantively flawed. 83 In setting the uranium standard, EPA first set the MCLG for uranium based on the risks of carcinogenicity. 65 Fed.Reg. at 76,712. EPA reasoned that because natural uranium is a radionuclide, and all radionuclides emit ionizing radiation that can cause cancer, there was no threshold level of safety for uranium. Id. EPA then concluded that the lowest feasible level for controlling the risks of cancer from natural uranium in drinking water was 20 µg/L. Id. Next, EPA addressed the effects of uranium on the human kidney, deciding that the best available science showed that uranium did have toxic effects on the human kidney, and that the level of uranium in drinking water that could be expected to protect human health was 20 µg/L. Id. at 76,713. EPA added that 30 µg/L would be expected to protect against the effects of kidney toxicity, id. at 76,713-14, but that any higher level might result in serious adverse effects on human kidneys, id. at 76,714. Finally, EPA relied on its cost-benefit analysis to conclude that at 30 µg/L essentially the same health benefits could be achieved at much lower cost compared to the 20 µg/L level. Id. EPA therefore set the uranium M.C.L. at 30 µg/L. 84 EPA relied on the LNT model in setting the MCLG for uranium at zero. 65 Fed. Reg. at 76,712. According to petitioners, there is no evidence in the record to support linearity and no evidence which detracts from the weight of the scientific evidence that supports the application of a non-linear model. Petitioners' Br. at 52. There was evidence in the record, primarily provided by RSH, that radionuclides in general only cause harm above a certain threshold level. There were also specific critiques of the linearity model as applied to uranium. However, the bomb studies in the record provide ample support for the linearity model, see 65 Fed.Reg. at 76,721, and there is also evidence in the record that uranium may be a carcinogen without a threshold level of safety. EPA noted that there is clear evidence that uranium (as with all radionuclides in general) emits ionizing radiation, that ionizing radiation causes genetic defects, and that genetic defects may lead to cancer. See 65 Fed. Reg. at 21,587, 21,600; 65 Fed.Reg. at 76,721. Although this evidence is based on enriched uranium, that does not exclude the possibility that natural uranium may have the same impact. EPA noted that the impacts of natural uranium may be difficult to detect because of the small doses of radiation involved and the comparatively small changes in cancer risk that would result; moreover, the pathway for causation would be the same for both enriched and natural uranium. 85 The resolution of this contradictory data lies well within EPA's expertise. Chlorine Chemistry Council, on which petitioners rely, is not to the contrary. In that case, the court concluded that EPA's reliance on the LNT model was inappropriate because EPA itself concluded that the chemical in question (chloroform) only caused harm above a threshold level. 206 F.3d at 1288. EPA failed to change the MCLG from zero because it wanted to wait for an additional report from SAB. Id. The court held that EPA's decision was arbitrary and capricious inasmuch as EPA had already concluded that the best science showed that there was a threshold effect, and EPA could always justify delay by stating that it wanted to wait for additional evidence to come in. Id. at 1290-91. In the instant case, by contrast, EPA maintains that the best available evidence still shows that uranium is a non-threshold carcinogen. Given the contradictory evidence in the record, there is no basis for the court to override EPA's decision for this is not a situation where there is simply no rational relationship between the model chosen and the situation to which it is applied. Am. Iron & Steel Inst. v. EPA, 115 F.3d 979, 1004 (D.C.Cir.1997) (quotation omitted). 86 Petitioners' next contention is that EPA did not follow its own procedures for classifying carcinogens when it set the MCLG for uranium at zero. According to petitioners, EPA classifies substances as having an M.C.L. of zero when the substance falls into one of three groups: 87 Group A, human carcinogens based on strong evidence of carcinogenicity from drinking water ingestion or sufficient evidence from epidemiological studies; Group B-1, probable human carcinogen based on at least limited evidence of carcinogenicity based on epidemiological studies in humans; Group B-2, probable human carcinogen based on sufficient evidence in animals and inadequate evidence or no data from epidemiological studies in humans. 88 Petitioners' Br. at 53. EPA does not contest petitioners' characterization of its classification process, but denies that it misapplied it in this case. 89 Apparently EPA classifies all radionuclides as Group A carcinogens based on the fact that they emit ionizing radiation that can cause cancer. 65 Fed.Reg. at 76,721. Again, this is a reasonable conclusion by EPA based on the evidence in the record. EPA is not relying on data from natural uranium, any effect of which EPA has concluded might be very difficult to detect through epidemiological or laboratory studies, but instead is relying on an extrapolation from other radionuclides and the laboratory and epidemiological data associated with those compounds. See 65 Fed.Reg. at 76,721; see also 56 Fed.Reg. at 33,071-72. Although studies to date may not have detected any impacts of natural uranium on cancer rates when it is ingested in drinking water in humans, EPA could reasonably conclude that based on the known carcinogenic potential of similar substances, natural uranium should also be considered a Group A carcinogen. 90 Petitioners make much of statements by EPA in its proposed rule in 1991 on a uranium MCLG, where EPA noted that [s]tudies using natural uranium do not provide direct evidence of carcinogenic potential in animals and that [e]xisting human epidemiology data are inadequate to assess the carcinogenicity of uranium ingested in drinking water. 56 Fed.Reg. at 33,076. However, EPA continued to explain in those statements that there were limitations to the studies that had found no effect, that other radionuclides were known to be harmful, that the pathways by which those radionuclides caused harm would be the same as for natural uranium, and that therefore the agency would continue to classify natural uranium as a Group A carcinogen. Id. 91 Petitioners also maintain that EPA improperly relied on data that uranium causes cancer by inhalation in concluding that it should be a Group A carcinogen, and state that this is a fatal flaw. Petitioners' Br. at 55. It is true that EPA has generally declined to rely on inhalation data when making decisions about the carcinogenic properties of a substance when ingested. See Int'l Fabricare Inst., 972 F.2d at 395. However, the statements made in the 1991 proposed rule do not indicate that EPA significantly relied upon the inhalation data. 56 Fed.Reg. at 33,076. 92 Petitioners further maintain that EPA should be forced to treat radionuclides in the same manner that it treated asbestos, where EPA concluded that despite asbestos' status as a Group A or B chemical, it would not automatically be treated as a non-threshold carcinogen because the agency believed that the additional evidence indicates that the overall evidence of carcinogenicity via ingestion is limited or inadequate. National Primary Drinking Water Regulations; Final Rule, 56 Fed. Reg. 3,526, 3,534 (Jan. 30, 1991). However, as EPA points out, asbestos is a completely different chemical from natural uranium. Given the evidence for similar radionuclides, EPA could reasonably conclude that the minimal direct evidence for natural uranium's carcinogenicity should be treated differently from the slightly more substantial direct evidence for asbestos. 93 Finally, petitioners contend that EPA ignored a report by the ATSDR on the risks of natural uranium. The ATSDR report concluded that: 94 No evidence linking oral exposure to uranium to human cancer has been found. Although natural, depleted, or enriched uranium and uranium compounds have not been evaluated in rodent cancer bioassays by any route by the [National Toxicology Program], there is potential for the carcinogenicity of uranium, since it emits primarily alpha radiation. Nevertheless, no evidence has been found to associate human exposure to uranium compounds and carcinogenicity. The National Academy of Sciences has determined that bone sarcoma is the most likely cancer from oral exposure to uranium; however, their report noted that this cancer has not been observed in exposed humans and concluded that exposure to natural uranium may have no measurable effect. 95 Similarly, the results of several oral studies with uranium in several species were negative for evidence of cancer induction. 96 ATSDR, U.S. Dep't of Health and Human Servs., Toxicological Profile for Uranium 137-38 (1999) (citations omitted). In replying to commenters who relied on the ATSDR report, EPA stated that ATSDR's statement does not preclude human carcinogenesis. Comment-Response Document (response to comment 9.A.4). This appears to be a correct reading of the ATSDR report, and, again, EPA is generally entitled to rely on evidence from other radionuclides and the potential for cancer from natural uranium's emission of ionizing radiation in the face of the uncertainty inherent in any scientific study's failure to identify a significant effect. Nor does EPA's failure to mention the ATSDR in its NODA or its technical documents that accompanied the NODA mean, as petitioners maintain, that EPA did not rely on the best available science. The ATSDR report is not primary research based on ATSDR's own studies; instead, it is a summary and review of the literature that has been published, the same type of undertaking that EPA's NODA and technical documents performed. We fail to see how EPA's failure to mention the ATSDR report in these documents is fatal to its analysis. Further, EPA's response to the comments mentioning the ATSDR report is adequate. 97 Petitioners in a footnote of their reply brief also state, While EPA argues that FGR-13 represents EPA's `most sophisticated science,' EPA did not utilize FGR-13 to develop the uranium standard. EPA neither disputes nor discusses this point in its brief. Petitioners' Reply Br. at 33 n. 150 (citation omitted). Petitioners do not state what legal flaw results from EPA's failure to use FGR-13, although the implication is that EPA did not meet the best available science standard of the SDWA. However, petitioners' only references to this argument in their opening brief were two sentences that also referred to EPA's failure to discuss FGR-13 in setting the uranium MCL, without explaining the legal implication of that failure. This is the type of asserted but unanalyzed contention that the court will not address. See SEC v. Banner Fund Int'l, 211 F.3d 602, 613 (D.C.Cir.2000) (quoting Carducci v. Regan, 714 F.2d 171, 177 (D.C.Cir.1983)). 98 Because EPA's MCLG is proper, petitioners' challenge to the M.C.L. based on the MCLG fails. To the extent petitioners also challenge EPA's reliance on kidney toxicity data, data which it relied upon in setting the M.C.L. at 30 µg/L, the thrust of petitioners' challenge is that EPA relied on studies that showed risks so small that EPA could not determine whether exposure resulted in an adverse impact, that EPA admitted that human studies were uncertain as to the actual impacts on kidneys from uranium consumption, and that EPA's conclusions were primarily based on data from experiments on rats using uranyl nitrate, a compound of uranium, rather than natural uranium itself. Petitioners' Br. at 61. However, in the face of uncertain laboratory and epidemiological data, it was reasonable for EPA to take the risk-averse approach of relying on the animal laboratory data to develop a lower standard. 99 Regarding petitioners' challenge to EPA's decision to set the final M.C.L. at 30 µg/L based on its cost-benefit analysis, the court's review is limited to determining whether EPA's analysis and final cost-benefit decision is arbitrary and capricious. 42 U.S.C. § 300g-1(b)(6)(D). Petitioners contend that EPA should have compared the cost per cancer case avoided: 100 When EPA selected from the acceptable uranium levels, EPA should have compared the cost per cancer case avoided for each proposed uranium MCL. EPA did not do that. Had the agency done so, it would have found that the incremental cost savings associated with raising the standard from 30 µg/L to 40 Sg/L ($64.1 million) was even higher than the incremental cost savings that prompted EPA to raise the standard from 20 µg/L to 30µg/L ($45.2 million) while still achieving an acceptable cancer risk. Thus if EPA applied the same analysis to the cost differences between 30 µg/L and 40 µg/L, as it did to the costs between 20 µg/L to 30 µg/L, it would have concluded that an increase to 40 µg/L was appropriate. 101 Petitioners' Br. at 32. The figures that petitioners cite in their brief are the aggregate amounts of money saved by relaxing the standards; at no point did petitioners discuss the increase in the number of cancer deaths or cases that would occur if the standards were relaxed. By definition, however, that increase must be considered in order to compare the cost per cancer case avoided, as petitioners request. In other words, petitioners' contention is internally inconsistent. Furthermore, a review of EPA's cost-benefit analysis shows that the cost per cancer case avoided is lower between 30 and 40 µg/L compared to between 20 and 30 µg/L, contrary to petitioners' assertions. Most importantly, EPA concluded that kidney risks increased substantially above 30 µg/L, sharply increasing the benefits foregone by raising the standard above that point. 65 Fed. Reg. at 76,713-14. EPA's decision therefore was not arbitrary and capricious.