Opinion ID: 423907
Heading Depth: 2
Heading Rank: 1

Heading: Probabilities

Text: 46 The District Court did not disagree with the Department's basic assessment of probabilities: DOT's conclusion that high-consequence accidents are very unlikely is supported by the record. 539 F.Supp. at 1265. However, the Court faulted the Department's probability assessment because it rested on several preliminary estimates that were themselves subjects of some dispute. For instance, experts disagreed about the number of large-quantity shipments that would occur in the future. In addition, there was some controversy over the Department's assumptions about cask integrity during an accident. The District Court was also concerned that the Department did not fully consider the manner in which human error might affect its probability estimates. Finally, the Court criticized the Department for not explicitly dealing with the degree to which the risks of sabotage might affect the probability of a high-consequence accident. 47 Number of Shipments. Not surprisingly, experts disagree over how many shipments of large-quantity radioactive materials will be made in the future. In 1977, the NRC study known as NUREG-0170 predicted that there would be 1,911 shipments a year by 1985. See NUREG-0170, supra, at A-20 to -23; 539 F.Supp. at 1266. In 1979, another government report estimated that there would be no more than 641 such shipments in 1985. See Report to the President by the Interagency Review Group on Nuclear Waste Management (1979) (hereinafter cited as IRG Report). Other sources noted by the District Court indicate that as many as 2,500 shipments may be made annually in 1985. See 539 F.Supp. at 1267 & n. 9. Faced with this uncertainty, DOT based its calculations on the relatively conservative 1977 NRC study. At various points in the Environmental Assessment, the Department recalculated its projections using the lower IRG Report. 48 The District Court faulted DOT's adoption of the NRC figures, supplemented by the IRG Report estimate, on the ground that the Department failed to discuss the great uncertainties that exist on this subject and the possibility that the number of such shipments will increase exponentially. Id. at 1267. Apparently, the District Court concluded that the uncertainties inherent in projecting shipment rates were sufficiently severe that the Department had to discuss the matter in its Environmental Assessment. 16 49 We do not accept this conclusion. The Department conservatively selected a projection that was on the high side of the various estimates. The highest estimates for 1985 reveal shipment levels only slightly more than 25 percent greater than the ones accepted by the Department. Inasmuch as these projections would have to be off by several orders of magnitude before there would be any substantial impact on the probability of a high-consequence accident, the Department cannot be faulted for not discussing the relatively minor difference among experts in predicting 1985 shipment levels. Certainly the Department did not act arbitrarily in failing to engage in such a discussion. 17 50 Cask Reliability. The District Court also criticized the Department for commenting in its Advance Notice of Proposed Rulemaking that packaging, in a severe transportation accident, would be expected to survive without any significant release of its contents. 45 Fed.Reg. at 7143. While Judge Sofaer did not label this comment as arbitrary, see 539 F.Supp. at 1268-69, he noted that several commentators had found the risks of cask failure more severe, and he suggested that the Department should have discussed the conflicting evidence at greater length. Id. 51 We think that DOT's assessment was well supported by two of the most complete studies on the transportation of radioactive materials. In particular, the NUREG-0170 study explicitly discussed cask reliability and explained why it found the risk of cask failure to be slight. See NUREG-0170, supra, at 5-20 to -21. As the District Court noted, in light of this scientific support, the Department's conclusion as to cask reliability was not arbitrary. Accordingly, it should not be susceptible to attack on judicial review. 52 Human Error. The District Court also faulted DOT for relying on probability assessments that fail to take into account the potential effect of human error. 539 F.Supp. at 1269. This objection stems from the Court's concern that the Department unreasonably underestimated the likelihood of high-consequence accidents by assuming that every shipment of large-quantity radioactive materials would be packaged and handled without human error. The Court apparently feared that inevitable human mistakes would make large-quantity shipments more susceptible to leakage and contamination during an accident than the Department had assumed. Id. 53 This criticism is unjustified. Both the NUREG-0170 study and the 1980 Sandia Report analyzed the impact of human error. As the District Court noted, the Sandia Report devoted a chapter to the subject, see Sandia Report, supra, at 71-84, and the NRC also discussed the matter under the heading of Abnormal Transport Occurrences, NUREG-0170, supra, at 4-31 to -33. The NRC report indicated that human errors compromise cask integrity in only a small fraction of shipments. Since large-quantity shipments are packed in such massive containers, human error is even less likely to affect overall package integrity of these shipments. Id. at 4-44 to -48. The Sandia Report agreed that [m]ost human errors do not produce compromises of package integrity. Sandia Report, supra, at 15. In light of the extremely low probability that any cask involved in a truck accident would also be compromised by human error, it does not seem to be reasonable to criticize DOT for not factoring this contingency into its calculations. Moreover, the Department corroborated its probability estimates by looking to the historic accident rates. Since the effect of human error is inevitably included in the historic rate of accidents, the Department, at least implicitly, considered human error in its probability assessment. For a source of risk this insignificant, implicit consideration was adequate. 54 Sabotage Risks. In its advance Notice of Proposed Rulemaking, DOT acknowledged that many observers had expressed concern over the possibility that saboteurs or terrorists might disrupt nuclear shipments and precipitate high-consequence accidents. The Department declined to assess this possibility on jurisdictional grounds: 55 Development of the current DOT proposal reflects existing arrangements between DOT and NRC wherein NRC exercises responsibility for any necessary physical security requirements during transportation. The DOT proposal is therefore directed at reducing impacts associated with normal and accident situations arising in transportation, while NRC is concerned with preventing malicious or deliberate release of radioactive materials. 56 45 Fed.Reg. at 7144. In 1979, the NRC had promulgated interim security rules governing the transportation of irradiated fuels, see 10 C.F.R. §§ 73.25-.37 (1982). The Department's sole response to the threat of sabotage was to propose extending the NRC regulations to shippers outside the NRC's jurisdiction. 57 The District Court had no complaint with DOT's decision to defer to the NRC as the appropriate agency for supervising matters of physical security. Nevertheless, Judge Sofaer felt that the Department should have included a discussion of sabotage in its assessment of the probability of high-consequence accidents. Under regulations of the Council on Environmental Quality, agencies should consider [t]he degree to which the possible effects on the human environment are highly uncertain or involve unique or known risks. 40 C.F.R. § 1508.27(b)(5) (1982); see DOT Order 5610.1C (Sept. 18, 1979). Both the Sandia Report and the NRC have accepted that sabotage presents a real although unquantifiable risk for the transportation of large-quantity radioactive materials. See Sandia Report, supra, at 85 (Sabotage involves human motivations and the probability of human actions which are unquantifiable with our present knowledge.); 45 Fed.Reg. 37,402 (1980) ([E]stimates of the probability of successful sabotage of spent fuel shipments cannot be made with any confidence.). However, other experts have insisted that sabotage-induced, high-consequence accidents are essentially impossible. NUREG-0170, supra, at 7-2. The District Court concluded, [G]iven the conflicts in the underlying data, [DOT] was obligated to state its view on the probability of such an event, even if that view was only that no estimate could reasonably be made. 539 F.Supp. at 1271. 58 With respect to environmental consequences that are only remote possibilities, an agency must be given some latitude to decide what sorts of risks it will assess. See Natural Resources Defense Council, Inc. v. NRC, 685 F.2d 459, 516, 540-45 (D.C.Cir.1982) (Wilkey, J., dissenting), rev'd, --- U.S. ----, 103 S.Ct. 2246, 76 L.Ed.2d 437 (1983). Here DOT simply concluded that the risks of sabotage were too far afield for consideration. To a large degree this judgment was justified by the record. Substantial evidence indicated that sabotage added nothing to the risk of high-consequence accidents. Even the least sanguine commentators could say only that sabotage added an unascertainable risk. In light of these conflicting points of view, it was within DOT's discretion not to discuss the matter further beyond adopting the NRC security requirements.