Opinion ID: 185864
Heading Depth: 1
Heading Rank: 5

Heading: THE MERITS OF THE RADIUM MCLs

Text: 70 Next, petitioners challenge the MCLs EPA set for radium-226 and radium-228. We review the rulemaking proceeding and the final rule under the APA and will reverse an EPA action only if it is `arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.' Int'l Fabricare Inst. v. U.S. EPA, 972 F.2d 384, 389 (D.C.Cir.1992) (quoting 5 U.S.C. § 706(2)(A)). Further, we will give an extreme degree of deference to the agency when it `is evaluating scientific data within its technical expertise.' Huls Am., Inc. v. Browner, 83 F.3d 445, 452 (D.C.Cir.1996) (quoting Int'l Fabricare Inst., 972 F.2d at 389; citing Marsh v. Oregon Natural Res. Council, 490 U.S. 360, 377, 109 S.Ct. 1851, 1861, 104 L.Ed.2d 377 (1989)). Nonetheless, our review must ensure that the EPA has examined the relevant data and has articulated an adequate explanation for its action. Int'l Fabricare Inst., 972 F.2d at 389. 71 As noted above, EPA set interim MCLs for each isotope at 5 pCi/L in 1976 and in 1991 proposed a new M.C.L. of 20 pCi/L for each. See 56 Fed.Reg. at 33,082. The agency based the 1991 MCLs on the RADRISK risk assessment model, with adjustments to conform with data from epidemiological studies. See id. at 33,056, 33,073-74. In the 2000 Final Rule the agency used a newer risk assessment model, set out in Federal Guidance Report No. 13, Keith F. Eckerman et al., EPA, Federal Guidance Report No. 13: Cancer Risk Coefficients for Environmental Exposure to Radionuclides (1999) (hereinafter FGR-13), see 65 Fed.Reg. at 76,735, and, based thereon, decided to retain the original 1976 MCLs of 5 pCi/L, see id. at 76,712, 76,748 (codified at 40 C.F.R. § 141.66). Petitioners contend that EPA's decision to retain the lower MCLs violates the SDWA because it is not based on the best available science, as required by the 1996 amendments to the SDWA which state that: 72 In carrying out this section, and, to the degree that an Agency action is based on science, the Administrator shall use — (i) the best available, peer-reviewed science and supporting studies conducted in accordance with sound and objective scientific practices; and (ii) data collected by accepted methods or best available methods (if the reliability of the method and the nature of the decision justifies use of the data). 73 42 U.S.C. § 300g-1(b)(3)(A). We disagree. 74 Petitioners' primary contention is that EPA ignored the epidemiological studies on which it relied in 1991 and failed to reconcile the results of the FGR-13 model with the data therefrom. Specifically, petitioners point to studies of watch dial painters who, in the early 20th century, ingested radium-226 and radium-228 when they inserted luminescent paint brushes into their mouths to sharpen the tips. In 1991 EPA modified the results of the RADRISK assessment in response to concerns expressed by EPA's Science Advisory Board (SAB), based on epidemiological evidence that included the dial painter data, that the results overstated the risk of leukemia and understated the risk of head cancer. Petitioners contend the agency arbitrarily ignored the dial painter data. Contrary to petitioners' claim, the record reveals that the agency did rely in part on the dial painter data which are reflected to some degree in the FGR-13 model. In other respects the agency adequately explained its reasons for rejecting the data. 75 First, the FGR-13 model's coefficients for both leukemia and bone cancer were adjusted to compensate for their over- and under-prediction, respectively, based on the results of the dial painter studies. See FGR-13 at 174 (citing as basis for FGR-13 leukemia relative biological effectiveness factor 1994 EPA document Estimating Radiogenic Risks, which, in turn, explains that factor was adjusted because of evidence it was too high, citing 1991 proposed rulemaking); 65 Fed.Reg. at 76,722 (citing dial painter data as basis for doubling risk coefficient for head and bone cancer combined). 14 In large part, however, the FGR-13 model relies on alternative epidemiological data from studies of Hiroshima and Nagasaki atomic bomb survivors and, to a lesser extent, studies of medical exposure to radium-224, FGR-13 at 173, and provides substantial reasons for doing so. The Final Rule sets forth specific grounds for downplaying the dial painter studies: (1) no one knows the quantity of radium ingested in those studies, so dose estimates are speculative and (2) the high mortality in some groups, and the small numbers of subjects in all exposure groups, would impair use of the data to develop dose response relationships. 65 Fed.Reg. at 76,721; see also Comment-Response Document 3-11 to 3-13 (response to comment 3.B.3). In addition, the FGR-13 model identifies a number of advantages to the alternative epidemiological data, in particular the bomb survivor studies: the large, relatively healthy population at the time of exposure, wide range of reasonably well established doses to individual subjects, large, well matched control group, and detailed, long-term epidemiological follow-up. FGR-13 at 173. 76 Without contesting the factual bases for EPA's preference, see Petitioners' Br. at 40 ([T]hese observations may be accurate.), petitioners point to disadvantages they see in the alternative data: the bomb studies also involve estimates, the bombing contamination was not limited to radium-226 and -228 and the contamination was largely external exposure rather than ingestion. Given the relative advantages EPA found in the bomb survivor studies, however, we defer to its decision to use the FGR-13 model because it bears a rational relationship to the characteristics of the data to which it is applied. See Nat'l Wildlife Fed'n v. EPA, 286 F.3d 554, 565 (D.C.Cir.2002) (We may reject an agency's choice of a scientific model `only when the model bears no rational relationship to the characteristics of the data to which it is applied.') (quoting Appalachian Power Co. v. EPA, 135 F.3d 791, 802 (D.C.Cir. 1998) (citing Am. Iron & Steel Inst. v. EPA, 115 F.3d 979, 1005 (D.C.Cir.1997); Chem. Mfrs. Ass'n v. EPA, 28 F.3d 1259, 1265 (D.C.Cir.1994))); cf. Am. Forest & Paper Ass'n, Inc. v. EPA, 294 F.3d 113, 121 (D.C.Cir.2002) (applying rational relationship standard and upholding EPA's reasoned preference for one methodology of calculating safe exposure levels over alternative methodology). We also conclude that EPA adequately responded to comments critiquing its reliance on the bomb studies. 77 Petitioners further contend that the dial painter data require the use of a quadratic dose-response curve for bone cancer, that is, one based on `a model which assumes that the excess risk is proportional to the square of the dose, meaning that low dosage presents no appreciable cancer risk,' Respondent's Br. at 68 n. 32 (quoting Nat'l Acad. of Scis. Comm. on the Biological Effects of Ionizing Radiation, Health Risks of Radon and Other Internally Deposited Alpha-Emitters IV (1988)) (emphasis added), rather than the linear, non-threshold (LNT) model used by EPA, which assumes that the risk is directly proportional to the dosage and that there is no threshold dosage below which there is no risk, see FGR-13 at v. Here, again, the agency sufficiently justified its choice of model to satisfy the rational relationship standard. 78 First, while acknowledging that the dial painter data suggest a quadratic, rather than linear, dose response curve, EPA concluded that the data are of limited value for the estimation of risk because the various reliability problems noted above (radium dosimetry, the high mortality in some groups, and the small numbers of subjects in all exposure groups) would impair use of the data to develop dose response relationships. 65 Fed.Reg. at 76,721. In particular, EPA concluded that there just are not enough subjects at lower dose levels to show the risk, giving the illusion of a threshold. Id. at 76,722. 79 Petitioners also assert the radium-224 exposure study results, from which EPA inferred that radium-226 and -228 can cause cancer of body parts other than the bone or head, are misleading because isotope -224 has different emissions from -228 and a far shorter half-life than either -226 or -228. Petitioners point out that EPA itself observed in the NODA that such different characteristics can affect human health differently. EPA made the observation, however, in explaining why -224 had been and might again be considered less risky in degree than the other two isotopes, not because of any qualitative difference in effect. See 65 Fed.Reg. at 21,585-86. Petitioners further contend that there were no data showing that any radium isotope, even radium-224, caused cancer in the esophagus, stomach, colon, lung, skin, ovary, or kidney. Petitioners' Br. at 43. In the Final Rule, however, EPA expressly states that patients treated with radium-224 were found to have significant increases in breast cancer, soft tissue sarcomas, liver cancer, thyroid cancer, cancers of urinary organs, and leukemia. 65 Fed.Reg. at 76,722 (emphasis added). Soft tissue sarcomas, EPA points out, can include any tissue in the body except cortical and trabecular bone. Respondent's Br. at 72 n. 34 (citing FGR-13 at GL-9). In sum, EPA was justified in relying on the radium-224 studies for its conclusion that, [g]iven our understanding of radium metabolism and the effects of alpha irradiation, it is expected that ingestion of any of the radium isotopes will increase the risks for various types of cancer other than bone. 65 Fed.Reg. at 76,722. 80 As additional justification for its model choice, EPA noted that the LNT model derives support from the linear dose-response relationships observed for most types of cancers in the intermediate- to high-dose range for atomic bomb survivors, and from results of molecular and cellular studies. 65 Fed.Reg. at 76,721. The latter studies, EPA explained, have shown that a single radiation track traversing a cell nucleus can cause unrepaired or misrepaired DNA lesions and chromosomal aberrations and that DNA lesions and chromosomal aberrations can lead to cancer. Id. From these data, EPA inferred, logically enough, that the probability of DNA damage and carcinogenesis is linearly proportional to the dose. Id. EPA further noted that its use of the LNT model for radionuclides is entirely consistent with all past and current observations and recommendations of a number of national and international science organizations 20 and that the U.S. Department of Energy, the U.S. Nuclear Regulatory Commission, and other Federal and State agencies with regulatory authority over radioactive materials also apply the LNT model as the basis for setting regulations and guidelines for radiation protection. Id.; see also FGR-13 at v ([S]everal recent expert panels ([United Nations Scientific Committee on the Effects of Atomic Radiation 1993, 1994; National Radiation Protection Board 1993; and the National Council on Radiation Protection and Measurements 1997]) have concluded that the LNT model is sufficiently consistent with current information on carcinogenic effects of radiation that its use is scientifically justifiable for purposes of estimating risks from low doses of radiation. As a practical matter, the LNT approach is universally used for assessing the risk from environmental exposure to radionuclides as well as other carcinogens.) 21 81 Finally, petitioners contend EPA did not demonstrate that the FGR-13 model represents the best available, peer-reviewed science, as required by § 1412(b)(3)(A) (In carrying out this section, and, to the degree that an Agency action is based on science, the Administrator shall use — (i) the best available, peer-reviewed science and supporting studies conducted in accordance with sound and objective scientific practices....). As set out above, however, EPA adequately explained, based on scientific data, why it prefers the FGR-13 model and the epidemiological data it used over the dial painter studies and the approaches based thereon that petitioners endorse. Further, as EPA notes, the SAB, whose imprimatur petitioners particularly esteem, reviewed and approved the FGR-13 methodology as it was employed in a 1994 EPA document Estimating Radiogenic Cancer Risks, and also reviewed and commented on the interim version reported in 1998, see FGR-13 at vi. 22 The substantial scientific support on which EPA relies for selecting the FGR-13 model (and in particular its LNT approach) distinguishes this case from Chlorine Chemistry Council v. EPA, 206 F.3d 1286 (D.C.Cir.2000), in which the court found EPA's use of a default assumption of linearity and zero MCLG violated the SDWA because it openly overrode the `best available' scientific evidence, which suggested that chloroform is a threshold carcinogen — a concession EPA had made at oral argument in that case. See 206 F.3d at 1290, 1291.