Full opinion text
AMENDED OPINION SOFAER, District Judge: On January 19, 1981, the United States Department of Transportation (“DOT”) published a “Final Rule” concerning the transportation of radioactive materials pursuant to its authority under the Hazardous Materials Transportation Act (“HMTA”), 49 U.S.C. §§ 1801-1812 (1976). The rule, scheduled to take effect on February 1, 1982, would permit the shipment by road throughout the nation of all types of radioactive materials. One avowed purpose of the rule was to override local prohibitions against the shipment of radioactive materials, particularly a local regulation adopted by the Board of Health of New York City (“City”) on January 15, 1976. The City commenced this action on March 25, 1981, seeking to invalidate DOT’s rule or, at least, to prevent it from overriding the City’s regulation. The State of New York intervened as a plaintiff, moving for discovery and a preliminary injunction against enforcement of DOT’s rule within the State’s borders; the Town of Brookhaven and Sullivan County, New York, joined the City’s and State’s efforts. The United States has been joined in its defense of DOT’s rule by numerous intervening power companies as well as by several amici curiae. Plaintiffs seek relief on numerous grounds. Several are meritless. Indeed, the welter of arguments contained in plaintiffs’ papers tends to obscure the fact the DOT’s actions are challenged meaningfully only insofar as they relate to the highway transportation of spent fuel from nuclear reactors and other large-quantity shipments of radioactive materials through densely populated areas such as New York City. In all other respects, the administrative record and the law supports DOT’s Final Rule. Insofar as DOT’s actions require states and localities to permit the highway transport of spent fuel and other large-quantity shipments through densely populated areas, the record developed by DOT cannot justify the challenged rule. The agency has failed to fulfill its responsibilities under the National Environmental Policy Act (“NEPA”), 42 U.S.C. §§ 4321-4347 (1976), and under the regulations promulgated under NEPA by the Council on Environmental Quality and by DOT itself. In particular, DOT has failed adequately to evaluate and to address itself to the problems posed by low-probability/high-consequence occurrences that are concededly “credible.” NEPA requires that an agency confronted with these problems, fundamental in a society dependent on inherently dangerous technologies, conduct a thorough examination and make determinations that are susceptible to review concerning: (1) the probability of the occurrence contemplated; (2) the potential consequences of such an occurrence; and (3) the environmental risk reflected by the probability and the consequences estimated. Because its environmental evaluation is deficient in all three respects, DOT’s Environmental Assessment is inadequate, and DOT’s finding that its action will have no significant environmental impact — and therefore that no environmental impact statement need be prepared — is insufficiently supported by the present record. Furthermore, DOT has failed adequately to consider alternatives to highway transport that might reduce or eliminate the risks posed to urban areas by low-probability/high-consequence accidents or by malevolent acts. Even if DOT could lawfully choose to regulate only highway transport at this time, it cannot rationally evaluate the option of taking no action without examining at least superficially the availability of nonhighway modes to accommodate shipments prevented by local and state laws from crossing densely populated areas. DOT has therefore failed to perform its obligation to “study, develop, and describe” appropriate alternatives. Apart from DOT’s obligation under NEPA to evaluate more fully the environmental consequences of its proposed rule, HMTA imposes similar duties on DOT and in addition sets limits on the agency’s authority to deem certain risks acceptable. For the same reasons DOT’s analysis is invalid under NEPA, its adoption of the challenged rule was an arbitrary and capricious exercise of its rulemaking authority under HMTA: DOT inadequately considered the risks of highway transport and the need, given potential alternatives, to impose those risks on the public. Further, DOT erroneously concluded that it is free under HMTA to subject unwilling states and localities to risks of potential catastrophe that DOT itself deemed “credible” and “important” when those risks are avoidable. HMTA mandates that in exercising its regulatory power DOT avoid where reasonably possible all significant risk not inherent in the transportation of hazardous substances. In adopting a new rule covering the transportation of spent fuel and other large-quantity radioactive materials, DOT must be guided by Congress’ policies, not by its own perception of acceptable risk. On the present record, DOT’s regulation is unreasonable in light of the properly applicable legal standards. The Court’s role in this case is to conduct a “searching and careful” review of DOT’s actions, but only in order to determine whether the agency has acted reasonably in fulfilling its statutory obligations. Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U.S. 402, 416, 91 S.Ct. 814, 823, 28 L.Ed.2d 136 (1971). The nature of contemporary scientific disputes requires a court to give close attention to detail, to ensure that it neither fails to perform its duty of careful review, nor goes beyond its limited role because of any failure to give proper weight to all the evidence supporting the agency’s judgment. A full review of the record is therefore necessary to identify all the evidence actually considered or implicitly supporting DOT’s conclusion. After that review the opinion examines plaintiffs’ numerous contentions. I. Factuai Background for DOT’s Action One of the problems created by the use of radioactive materials in American medicine and industry is the need to transport them. Our society is highly dependent on radioactive materials. In medicine, gamma-ray-emitting isotopes are commonly used to image specific areas and organs of the body. Radioisotopes of iodine are used to diagnose and treat thyroid disorders; other isotopes are used in millions of scanning procedures annually. Large quantities of Co-60 (cobalt) or Cs-137 (cesium) are used for cancer treatment, research, and large-scale food sterilization. Well-logging firms use radioisotopes to assess a well’s capability; radioactive tracers are also used for this purpose. The radiography industry uses certain isotopes that emit high-energy gamma rays to examine the structural integrity of welded joints, particularly in large pipes and frames. Radioactive materials are especially effective in a large variety of gauging applications. And, of course, the nuclear power industry uses radioactive materials, and generates large quantities of irradiated (spent) fuel. All of these uses require transport to one degree or another, often at several different stages, including manufacture, use, and disposal. As the use of radioactive materials has become increasingly common, public awareness of the dangers posed by their transportation has heightened. Since the middle of the 1970s, governmental authorities on federal, state, and local levels have begun to address the problem. In 1975 Congress passed HMTA to centralize authority in DOT to promulgate and enforce regulations to protect the public against “the risks to life and property which are inherent in the transportation of hazardous materials,” including radioactive materials. 49 U.S.C. § 1801 (1976). The act specifically empowers the Secretary of Transportation to issue routing rules for the safe transportation of radioactive materials. Id. § 1804(a). Congress provided expressly for the preemption of state and local rules inconsistent with the act or with regulations adopted under it, except for inconsistent rules that DOT finds ensure equal or greater public safety than the inconsistent federal requirements and do not unreasonably burden interstate commerce. Id. § 1811. DOT regulations that preexisted the passage of HMTA required motor vehicles containing hazardous materials to use routes that “do not go through or near heavily populated areas, places where crowds are assembled, tunnels, narrow streets, or alleys,” unless “there is no practicable alternative.” 49 C.F.R. § 397.9(a) (1980). Every vehicle containing hazardous materials was required to comply with local driving and parking laws, unless the local laws were at variance with a more stringent rule imposed by DOT; and state or local laws governing transport through vehicular tunnels used for mass transportation were specifically exempted from any arguable preemption. 49 C.F.R. §§ 177.810, 397.3 (1980). These regulations continued in effect after HMTA’s adoption in 1975. The Final Rule challenged in this proceeding is the direct result of DOT’S determination to deal with the disruptive effects of a health regulation, adopted on January 15, 1976, by New York City’s Board of Health as an amendment to its Health Code, prohibiting the commercial transport into or through the City of large-quantity or high-level radioactive materials. N.Y.C. Health Code § 175.111(7). Complaint of New York City, Ex. A. The amendment effectively prevented the Brookhaven National Laboratories (“BNL”) from shipping spent nuclear fuel from Long Island through densely populated areas of the City by truck. In addition the regulation would prevent shipments of spent fuel and other material from traveling through the City from the Shoreham Nuclear Unit, expected to begin operating in 1983. On the very day that the City adopted the regulation, the federal government sued to have it declared preempted and unenforceable. Judge Inzer B. Wyatt denied preliminary relief on January 30,1976, and the case was subsequently transferred to the suspense docket by stipulation. United States v. City of New York, 76 Civ. 273 (IBW). On March 1, 1977, Associated Universities, Inc., consisting of nine institutions whose representatives formed the BNL Board of Directors, sought a declaration from DOT that the City’s regulation was inconsistent with HMTA and with DOT regulations. DOT denied the request on April 20, 1978, ruling that the City regulation was in effect a routing requirement and that, although DOT had the power to preempt local routing rules, the agency had not yet exercised that power. DOT recognized that the City had adopted its regulation because its public health officials had considered that, given the City’s dense population, “the consequences of a major accident are too extreme to be tolerable, however remote the probability.” 43 Fed.Reg. 16954, 16957 (1978). Even so DOT suggested that it disapproved of the City’s regulation. Id. at 16957-58. Since 1976 BNL has shipped spent fuel by water, via New London, Connecticut, although that option may have been made unavailable by local law. On August 17, 1978, DOT invited comment “on the need, and possible methods for establishing routing requirements under the Hazardous Materials Transportation Act applicable to highway carriers of radioactive materials.” 43 Fed.Reg. 36492 (1978). The “advance notice” made clear that it was motivated in particular by the fact that the City had prohibited highway transport of most commercial shipments of radioactive materials. It noted that other jurisdictions had adopted safety requirements imposing “significant additional responsibilities on shippers, carriers, or neighboring jurisdictions,” all of which “affect interstate commerce.” The notice proposed to examine the safety aspects of highway transport and the effects of existing regulations. Most significantly, DOT announced at that time that it intended to limit its consideration to highway routing, and would not consider alternative modes: Only highway routing of radioactive materials will be considered in this docket. This does not rule out the possible future consideration of materials in other hazard classes and other modes of transportation. However, highway transportation, of all four modes of transportation, offers the largest number of routing possibilities and the greatest access to population centers. Id. at 36492. The notice referred the public to several studies, including most notably the Final Environmental Statement on the Transportation of Radioactive Material by Air and Other Modes (“NUREG-0170”) prepared for the U. S. Nuclear Regulatory Commission (“NRC”) in December 1977. It also noted DOT’s intention to consider the results when available of NRC’s study, then underway, of transport through urban areas, eventually published as Transportation of Radionuclides in Urban Environs: Draft Environmental Assessment (NUREG/CR0743; SAND 79-0369) (1980) (“SANDIA”). Finally, the notice flatly asserted that, although its prior regulations left control of highway traffic of hazardous materials primarily to state and local regulation, those regulations reflected “the principle that such State and local regulation should not have the actual effect of altogether forbidding highway transportation between any two points, even where other modes of transportation are available.” 43 Fed.Reg. at 36493. DOT did not explain how it derived this principle, although DOT had itself ruled that the City’s regulation was consistent with federal law and with its own regulation, 49 C.F.R. § 397.9(a) (1980), requiring compliance wherever “practicable” with local rules that mandate avoidance of heavily populated areas. 43 Fed. Reg. at 16954. DOT scheduled a public hearing on its notice. The Director of the City’s Bureau of Radiation Control, Dr. Leonard R. Solon, submitted a statement proposing that DOT not limit itself to considering only highway transport. Dr. Solon suggested that barging spent fuel was feasible and that DOT should enlist the assistance of the Coast Guard and Department of Energy to develop plans for maritime transport. Solon Affidavit ¶ 11, New York City Notice of Cross-Motion for Summary Judgment [hereinafter “City Motion”] “This would minimize the public health risks of spent fuel transportation by bypassing populated areas.” City Motion, Ex. B at 11. In addition, DOT’s proposed rulemaking was specifically noted in the Report to the President by the Interagency Review Group on Nuclear Waste Management (March 1979) (“IRG Report”). Responding to the concerns of a highway-carrier representative regarding state and local restrictions, and of state and local officials regarding transportation through or near populated areas, the IRG Report stated that DOT’s rulemaking was an important step towards resolution of the issues. Although comments received by the IRG said that there was a special need for DOT to resolve the highway routing question, id. at 113, the IRG, consistent with its comments on NEPA’s requirement that alternatives be considered, id. at 21-22, articulated a broader view: DOT should proceed expeditiously to examine the desirability of Federally prescribed routing requirements for barge, rail, and highway shipment of radioactive wastes, as well as the question of to what degree local restrictions are appropriate. Id. at 112 (emphasis added). A. DOT’s Notice of Proposed Rulemaking On January 31, 1980, DOT published its proposed rule for the highway routing of radioactive materials, as well as a draft environmental assessment. 45 Fed.Reg. 7140 (1980). The agency again reviewed the history of New York City’s regulation and concluded that national action was necessary to prevent local and state rules from interfering with radioactive shipments by highway. The notice summarized accident data and, relying on NUREG-0170 and on the Sandia Laboratory’s draft report Transport of Radionuclides in Urban Environs: A Working Draft Assessment (May 1978), DOT concluded that the “estimated risks” from both accident-free highway transport and accidents “are within the magnitudes of other socially accepted risks, such as evidenced in highway traffic fatality rates.” The agency noted the public concern over highway transport of radioactive materials, but found it unjustified by the estimates: Public concern with radioactive materials transportation, however, is more profound than those estimates would suggest is justified. In part this concern reflects the distinction between risks which are likely to be concentrated and similar risks spread over differing times and locations. The annual death rate from passenger car accidents, for example, usually is perceived as less catastrophic than major aircraft accidents, although far more people die in automobile accidents. This distinction may reflect the perceived limits of society to deal with catastrophic occurrences. 45 Fed.Reg. at 7141. In fact, the agency found, risks expected from highway transport of radioactive materials are minimal. DOT took particular note of the possibility of a severe accident involving spent fuel or another type of large-quantity package. It found that “only large quantity packages pose even a remote risk of extraordinary or catastrophic accident consequences.” Id. at 7148. It pointed out that such an accident was extremely unlikely, because the casks used for spent fuel shipments are massive (up to 35 tons) and able to sustain great impacts without rupture. Recognizing, however, that NUREG-0170 reported that a rupture could conceivably occur in extreme circumstances, the notice went on to describe the consequences of several “worst case” accidents. Some of these hypothetical accidents, DOT noted, could be extremely serious, but the most serious “is likely only once in 25 billion years and is thought by MTB not to warrant undue concern. A more typical high speed collision and fire in a highway accident is not likely to result in extensive radiological injuries or damage from the presence of either Type A, Type B or large quantity packages of radioactive materials.” Id. at 7143. The notice also recognized the possibility of sabotage. This risk, too, was limited to spent fuel and other large-quantity shipments. Although the possibility of such an attack exists, DOT suggested “the likelihood of a successful act of sabotage that breaches a spent fuel cask and disperses its contents may be quite small.” Id. at 7150. Regulations established by the NRC for its licensees regarding shipments of spent fuel “will provide adequate physical protection” for licensees’ shipments. Finally, DOT maintained its resolve to refuse to consider alternative modes of transport. Despite the express suggestions of commentators that barging be considered where feasible, especially for spent fuel and other large-quantity shipments, the notice did not even mention barging. In a discussion of “Other Modes and Other Hazardous Materials,” the agency only raised and deferred consideration of routing spent fuel by rail. Id. at 7151-52. The Draft Environmental Assessment, moreover, considered only alternatives involving highways. The only option even arguably covering nonhighway transport — to take no action — gave no attention to barging as a potential means of eliminating the burden on commerce that some local rules might otherwise impose. The Assessment specifically found that taking no action would have few if any effects. Nevertheless, DOT rejected the no-action option and proposed to implement its previously suggested policy by making it absolutely clear that, irrespective of alternatives, any state or local rule preventing the use of highways for any type of shipment between any two points was inconsistent with DOT’s proposed rule: State and local requirements which apply to any person because that person transports radioactive materials are inconsistent with this subchapter if they have any of the following effects. (1) Completely prohibiting travel between any two points serviced by highway; (2) Prohibiting the use of an Interstate highway, including prohibition of travel based on time of day, without designation of an equivalent preferred highway as a substitute in accordance with the provisions of this section Id. at 7153 (proposed 49 C.F.R. § 177.-825(d)). The City responded to DOT’s proposed rule on January 30,1980. It took issue with DOT’s analysis of dangers in transporting spent fuel and other large-quantity shipments through densely populated areas. In addition, the City renewed its criticism of DOT’s refusal to consider the feasibility of transporting spent fuel by barge. It noted, in particular, that NUREG-0170, on which DOT placed great reliance for its findings and conclusions, had found barging a feasible alternative with respect to many reactor sites: The fact that transportation costs are so much lower for barges than for other modes makes this alternative certainly worth additional investigation. ■ Barge transportation of irradiated fuel may be a viable alternative, at least for some specific reactor sites, if not as a nationwide scheme. NUREG-0170 at 6-11. The City contended, moreover, that barge transport was safer than highway transport of large-quantity shipments through its densely populated limits. Finally, arguing that its regulation afforded greater protection without burdening interstate commerce, the City requested that DOT issue a nonpreemption ruling with its final rule, so as to preclude the existence of a period in which spent fuel shipments by highway would be made through the City while its nonpreemption request was pending. Complaint of New York City, Ex. D. DOT responded to the City’s nonpreemption request on July 31, 1980. It included the City’s comments in the record and agreed to consider them before taking final action. But it refused to docket the non-preemption request, because no final rule had been promulgated with which the City’s regulation could be deemed inconsistent. Douglas A. Crockett, then of DOT’S Office of Chief Counsel, raised no other objection to the City’s request at that time, and in fact suggested to then Corporation Counsel Allen G. Schwartz that “you may wish to renew your application at a more appropriate time.” City Motion, Ex. M. B. DOT’S Final Rule, HM-164 DOT published its Final Rule on January 19,1981, to take effect on February 1,1982. 46 Fed.Reg. 5298 (1981). In most respects, the rule follows the scheme earlier proposed. In general, the rule classifies covered materials as Type A, Type B, or large-quantity radioactive materials, which, respectively, must be packaged for shipment in Type A, Type B, or specially approved Type B containers. “Large quantity radioactive materials” embraces spent nuclear reactor fuel. 49 C.F.R. § 173.389 (1980). The rule specifies what shipments must be “placarded,” 49 C.F.R. §§ 172.403(d), 172.-504 (1980), leaving unplaearded shipments unregulated, as posing no hazard. For placarded shipments, the rule requires carriers to use routes that “minimize radiological risk,” but in general the rule does not mandate use of specified routes. For large quantity shipments, by contrast, HM-164 requires the use of “preferred routes” for highway transportation. In particular, HM-164 provides, in relevant part: Unless otherwise permitted by this section, a carrier and any person who operates a motor vehicle containing a package of large quantity radioactive material as defined in § 173.389(b) of this subchapter shall ensure that the vehicle operates over preferred routes selected to reduce time in transit, except that an Interstate System bypass or beltway around a city shall be used when available. (1) A preferred route consists of— (i) An Interstate System highway for which an alternative route is not designated by a State routing agency as provided in this section, and (ii) A State-designated route selected by a State routing agency (see § 171.8 of this subchapter) in accordance with the DOT “Guidelines for Selecting Preferred Highway Routes for Shipments of Large Quantity Radioactive Materials”. 46 Fed.Reg. at 5316-17 (to be codified at 49 C.F.R. § 177.825(b)) [hereinafter cited only to C.F.R.]. The “Guidelines” require that, in selecting a preferred route, the State routing agency analyze radiation exposure, costs, economic risks from accidents, public health risks, emergency response capabilities, evacuation plans, traffic fatalities and injuries, and the locale of special facilities. City Motion, Ex. W. The Final Rule deleted from the proposed official regulations the provision expressly declaring inconsistent all local bans on highway transport. Instead, DOT reiterated that position and policy at greater length in what was to become Appendix A to C.F.R. Part 177. 46 Fed.Reg. at 5317. State and local jurisdictions are informed how they “can exercise authority over motor carriers under [their] own laws in a manner that the Department of Transportation considers to be consistent with rules in Part 177.” The Appendix states, in relevant part: III. Large quantity radioactive materials A. State routing rules. A State routing rule which applies to large quantity radioactive materials is inconsistent with Part 177 if— 1. It prohibits transportation of large quantity radioactive materials by highway between any two points without providing an alternate route for the duration of the prohibition; or 2. It does not meet all of the following criteria: (a) The rule is established by a State routing agency as defined in § 171.8 of this subchapter; (b) The rule is based on a comparative radiological risk assessment process at least as sensitive as that outlined in the “DOT Guidelines”; (e) The rule is based on evaluation of radiological risk wherever it may occur, and on a solicitation and substantive consideration of views from each affected jurisdiction, including local jurisdictions and other States; and (d) The rule ensures reasonable continuity of routes between jurisdictions. B. Local routing rules. A local routing rule that applies to large quantity radioactive materials is inconsistent with this Part if it prohibits or otherwise affects transportation on routes or at locations either— 1. Authorized by Part 177, or 2. Authorized by a State routing agency in a manner consistent with Part 177. Under this interpretive policy, § 175.111(1) of the New York City Health Code is inconsistent with the routing rules of 49 C.F.R. § 177.825(b) because it effectively prohibits use of the highways for shipments through New York City of large-quantity radioactive materials. DOT persisted, in adopting the Final Rule, in refusing to evaluate alternative modes of transport. It resolved to consider “only routing requirements for radioactive materials shipped by highway, the focus of most State and local actions, rather than undertake a comprehensive regulatory proceeding to consider all classes of hazardous materials and all modes of transportation.” 46 Fed.Reg. 5300 (1981). The Regulatory Evaluation and Environmental Assessment filed with the Final Rule also reflected this policy. It restricted its consideration of alternatives to taking no action (which it found would have little or no effect), and to taking a variety of other actions, all involving highways. Environmental Assessment, DOT Motion, Ex. D. The ultimate basis for DOT’S Final Rule is “that the public risks in transporting these materials by highway are too low to justify the unilateral imposition by local governments of bans and other severe restrictions on the highway mode of transportation.” 46 Fed.Reg. at 5299. This same finding supports DOT’s policy decision in Appendix A to deem inconsistent with the Final Rule any nonfederal rule preventing highway transport: A State cannot make transportation between two points impossible by highway. The radiological risks in transporting large quantity radioactive materials by highway are small and total preclusion of shipments cannot be justified on that basis. Id. at 5313; see id. at 5317 (49 C.F.R. Part 177, app. A, pt. III(1)). See also id. at 5309: “[Pjackages of large quantity radioactive materials can be transported over any Interstate highway, and most other comparable [highway] routes, with a confident level of safety.” In reaching this conclusion, DOT was aware of the potential for a serious accident in a densely populated area. It stated at one point that the “accident rate is not the only important element to consider in assessing risk to the public — one must consider the consequences of a serious accident, even though the probability of that accident may be small.” Id. at 5301. It affirmed at another point that DOT, “also, is concerned with such events [as high consequence accidents] and is mindful of the large economic consequences estimated for such hypothetical events by [the recent SANDIA report]. These estimates relate to a scenario which assumes the worst credible accident for certain truck shipments of spent fuel and polonium in densely populated urban areas.” Id. at 5299. Nevertheless, DOT concluded, the potential consequences of such accidents did not warrant allowing a state or locality to prevent highway transport, at bottom because the consequences were highly unlikely, and “these currently low risks will be further minimized by the adoption of driver training requirements and provisions of a method for selecting the safest available highway routes for carriers of large quantity radioactive materials, as accomplished in this rule.” Id DOT stated its position with respect to low-probability/high-consequence accidents in very general terms. “Many commenters,” the agency contended, “seem to be concerned only with consequence — particularly high consequence accidents involving large quantity radioactive materials in a heavily populated urban center.” Id. A proper assessment of the risk of such accidents, DOT said, must be more balanced: [A]n assessment of risk to the public from accidents involving large quantity radioactive materials should include a balanced consideration of factors which affect both the likelihood of an accident as well as the consequences. Id. High-consequence accidents should be “of great concern,” said DOT, “but not to the extent that public policy on hazardous material routing should be formulated solely on the basis of avoiding such ‘worst case’ accidents.” Id. at 5315. See also id. at 5300. The probability of such accidents was low enough, in DOT’s view, for the overall risk to be deemed acceptable. If, in addition to low risk, “other factors” were considered by DOT in reaching its conclusion, they were not described as such. Two factors, however, seem to have been considered. First, DOT concluded that public concern over the worst-case accident is irrational, because the same public is willing to bear much greater risks, including the consequences of ordinary highway accidents. See p. 1245 supra. Second, DOT regarded local laws in particular as highly suspect and likely to reflect public irrationality. Indeed, the Final Rule and its accompanying documents are a veritable essay in political philosophy, expressing DOT’s skepticism of the capacity of localities to adopt rules worthy of national, or even regional, respect. The rulemaking, DOT noted, was necessary to “consider the overall safety impact of piecemeal, uncoordinated local actions on hazardous material transportation,” actions DOT characterized as “narrowly conceived.” 46 Fed.Reg. at 5300. Although it noted the argument of “commenters” that, in the United States, local governments have traditionally had primary responsibility for highway safety and for public health, as well as the duty to respond to and clean up after serious accidents, DOT explained: Local jurisdictions are inherently limited in perspective with respect to establishing routing requirements. While the Department recognizes that local governments are accountable only to their own citizens, such a limited accoüntability has- some undesirable effects. Id. While repeatedly expressing its resolve not to examine alternative modes of transport in its rulemaking, DOT nevertheless twice expressed the view that alternative modes would not clearly reduce public risks. Thus, early in its discussion of the Final Rule, DOT stated without elaboration or support: Other modes of transport generally do not appear to offer alternatives which clearly lower public risks to the extent that use of the highway mode should be substantially restricted. Id. at 5299. DOT’s second comment on the subject, and its most comprehensive statement of its understanding of its HMTA responsibilities, is found in the Supplement to Docket HM-164: Summary and Analysis of Public Comments, DOT Motion, Ex. E. In responding to criticism of its decision to refuse to consider alternative modes of transport that might avoid a possible catastrophe, DOT stated that it willingly assumed responsibility for imposing the risk, because the risk was small and could not significantly be reduced by resorting to other modes: A number of commenters do not share MTB’s opinion that this rulemaking be so severely limited. Although none of the proposed or adopted rules pertain to other modes or other hazardous materials the Bureau believes that a discussion of these comments is appropriate. The most prominent comments addressing this area question MTB’s failure to impose a requirement on shippers of large quantity radioactive materials packages to evaluate the risks identified with each mode or combination of modes and then select the method which is most favorable on the basis of the expected impacts on public health and safety. These eommenters go on to say that the potential for catastrophe does exist whenever large quantities of radioactive materials are transported in urbanized areas and that it is a proper function of government to safeguard its citizens from such a possible tragedy. In essence MTB finds itself in general agreement with with these comments and must conclude that the differences which exist are not of a philosophical nature but rather are represented by varying degrees of protection which reasonable minds may find difficult in reaching a consensus, [sic ] When differences such as these cannot otherwise be resolved a judgment must be made by the responsible party. In this case the MTB has primacy over hazardous materials transportation and believes that this exercising of its authority is in order. The determination made by MTB applicable to large quantity radioactive materials packages transported by public highway is that they can be shipped with confidence of an acceptable level of safety and therefore such packages should not be subjected to compulsory modal shifts which result in the fractional reduction of an otherwise low risk. This policy is consistent with MTB’s history of recognizing the inherent risks appropriate to the transportation of particular hazardous materials by each of the modes, and its reluctance to specify an order of precedence in the choices available to shippers regarding the physical state of their materials, packagings, quantity amounts, and the like. Such a policy would also not appear to violate recommendations made by the National Council on Radiation Protection (NCRP) concerning the maintenance of dose rates at levels which are “as low as reasonably achievable.” DOT Motion Ex. E, pt. H.2. The same assumptions that led DOT to discount the potential consequences of serious accidents led it to reaffirm its view that the possibility of sabotage did not warrant allowing states or localities to prohibit some shipments through or near densely populated areas. DOT Motion, Ex. E, pt. E at 6. C. The City’s Nonpreemption Request The City responded by letter to DOT’s Final Rule on March 20,1981, criticizing the rule’s premises at length, and renewing the City’s request for a nonpreemption ruling. City Motion, Ex. N. The City noted that DOT’s express declaration in Appendix A rendered the City’s regulation inconsistent, but the City insisted that its local ban afforded greater protection without imposing an unreasonable burden on commerce: The City believes that barging of large quantities of radioactive materials, and in particular spent nuclear fuel, achieve [sic] a level of safety greater than the highway transport authorized by the DOT rule, and at the same time, no unreasonable burden on commerce will be imposed. Id. at 2. The City’s letter referred again to NUREG-0170’s recognition of barging as a possibly viable alternative, and to a site-specific study confirming that barging could be used for spent fuel from the Shore-ham Nuclear Station. Barging, the City noted, has already been successfully used by Brookhaven National Laboratories and by others, and would make a serious accident much less likely. The letter asserted in particular: “Barge shipments to highway points avoiding New York City will eliminate the risk to the City’s residents and, at the same time, produce no increased risk of exposure to residents of other localities if the interconnection points between barge and highway are south of New York City.” Id. at 4 (emphasis added). DOT responded to this request by letter dated April 22, 1981. City Motion, Ex. 0. It stated that the MTB “will need to develop more information concerning the safety level and commercial burden associated with § 175.111 of the City’s Health Code before reaching a conclusion,” and proposed to extend the comment period until further notice, a proposal in which the City acquiesced. City Motion, Ex. P. DOT took no further action on the City’s request until after a meeting of DOT personnel with City representatives on December 21, 1981. At that time the City requested “a preliminary response to its March 20, 1981, application for a non-preemption determination.” The Court, in an Order entered on January 4, 1982, also requested DOT to state its position on the City’s application. On January 15,1982, DOT sent the City a seven-page letter, detailing the weaknesses and flaws in its nonpreemption request. Letter from Alan I. Roberts to Stephen P. Kramer (Jan. 15, 1982). The City’s regulation, DOT wrote, “is precisely the type of requirement ... that led to the adoption of the regulations with which the City’s requirement is inconsistent,” because the Department had already concluded that the public risks of highway transport were too low to justify local government bans such as the City’s. Id. at 2. Even if the ban provided greater safety without unreasonably burdening commerce, a nonpreemption ruling might not be granted. The City, DOT said, “must make a clear demonstration that, because of its peculiar circumstances, it is entitled to an exception from the general rules of HM-164 .... Without such a demonstration, the exception permitted by a non-preemption determination would, in effect, ‘swallow the rule’ and severely undermine the policies underlying HM-164.” Id. The legislative history “clearly indicates that” inconsistent requirements are to be deemed nonpreempted only when “shown to be clearly necessary.” Id. The City had failed in its application to demonstrate the exceptional circumstances required, because the application relied on the same studies DOT had used in reaching its conclusion that the risks of radioactive materials transport by highway are too low to justify local bans; because NRC itself had recently concurred in DOT’s conclusion; and because the “general statements” and “anecdotes” relied on by the City to establish the feasibility of barging were “of little value to DOT in attempting to determine the extent of increased costs and impairment of efficiency resulting from the City’s requirements.” Id. at 3. The City, moreover, relied “on a ‘worst-case’ approach to safety analysis which considers only the possible consequences of an accident and ignores the probability that such consequences would ever occur.” Id. HM-164 had “explicitly rejected the worst-case approach to safety analysis,” requiring that routing policy be based also upon “all other factors which contribute to the overall risk involved in transporting large quantity radioactive materials.” Id. Before DOT would proceed further with the City’s application, the City was required to provide “a detailed analysis” comparing the levels of safety and cost resulting from its regulation with those achieved by HM-164. The City would also have to identify in any renewed application all parts of “the public” affected by its proposal, id. at 4, and then estimate the risks from accident-free transport and from accidental release, on all population groups, for both the highway and barge alternatives. In addition, the City would have to perform an analysis of comparative costs, including initial capital investments and operating costs. Id. at 3-5. “The Department appreciates the degree of effort on the part of the City that the analysis described above will require. However, it is our firm view that that effort is required in order to substantiate the determinations required by § 112(b).” Id. at 5. Noting that Congress was considering a bill to require DOT to undertake the burden of analysis it was placing on the City, DOT expressed its willingness to hold, open the City’s requests pending Congress’ action on the bill “[i]f the City considers the analysis discussed above to be beyond its capabilities.” Id. The letter concluded with several technical objections that have little if any substantive significance, but do reflect the Department’s hostility towards the City’s application. DOT’s letter is clearly a ruling rejecting the City’s application as filed in March 1981, and mandating a massive demonstration by the City. The letter imposing these demands was written, moreover, nine months after the agency informed the City that its own MTB was collecting the material necessary to evaluate the City’s request, and only fifteen days before DOT’s rule was scheduled to take effect. DOT thereby effectively precluded the City from preparing a more detailed presentation and obtaining a definitive ruling on the merits of its application prior to the date on which the City’s ban was scheduled to be rendered unenforceable. II. DOT’s Authority to Adopt HM-164 The City and State of New York present several challenges to DOT’s authority to adopt its Final Rule, including Appendix A. The State claims that HMTA unconstitutionally delegates legislative authority to DOT, and that the Final Rule violates the Tenth Amendment of the Constitution of the United States by interfering unjustifiably with matters of state concern. Both plaintiffs argue that the Final Rule is unauthorized by HMTA, in that the statute permits only regulations that “promote” safety in every particular application. Finally, both contend that HMTA’s preemption provision implicitly prevents DOT from adopting regulations that preempt local rules that provide no less safety thán the regulation proposed and that do not unreasonably burden commerce. None of these arguments is valid. A. Constitutionality of HMTA’s Delegations Congress lawfully delegated to DOT both its rulemaking authority and the authority, under 49 U.S.C. § 1811(b) (1976), to make nonpreemption determinations. The rulemaking authority is constrained by the requirement that regulations rationally seek to protect the public from the risks of transporting hazardous materials. Id. § 1804(a). The nonpreemption decision is governed by the requirement that the non-federal rule both promote public safety no less than the federal rule and not unreasonably burden commerce. Id. § 1811(b). Both standards call for technical decisions that fall within DOT’s area of expertise, arid the public-safety standard is “sufficiently precise to apprise DOT both of its regulatory mission and the means to carry it out.” Memorandum of Law in Support of Motion for Summary Judgment by Defendant-Intervenors at 60. With respect to both these powers, therefore, HMTA’s delegations pass constitutional muster because Congress laid down sufficiently intelligible principles and clearly defined standards in one of DOT’s “areas of expertise.” National Nutritional Foods Ass’n v. Weinberger, 512 F.2d 688, 696 (2d Cir.), cert. denied, 423 U.S. 827, 96 S.Ct. 44, 46 L.Ed.2d 445 (1975); Currin v. Wallace, 306 U.S. 1, 59 S.Ct. 379, 83 L.Ed. 441 (1939). B. Validity of HM-164 Under the Tenth Amendment HMTA, and in particular its preemption provision, 49 U.S.C. § 1811(a) (1976), are well within the commerce power of Congress. “[W]hen Congress has determined that an activity affects interstate commerce, the courts need inquire only whether the finding is rational.” Hodel v. Virginia Surface Mining and Reclamation Ass’n, 452 U.S. 264, 101 S.Ct. 2352, 2360, 69 L.Ed.2d 1 (1981). Congress’ determination that the transportation of hazardous materials affects interstate commerce is rational. The spent fuel from the Brookhaven facility that is at issue in this case would, if the DOT regulations take effect, be trucked on Interstate highways across the New York border into New Jersey and eventually to upstate New York or South Carolina for storage. Further, the means adopted by Congress are “ ‘reasonably adapted to the end permitted by the Constitution.’ ” Id. at 2360. In order “to protect the Nation adequately against the risks to life and property which are inherent in the transportation of hazardous materials in commerce,” 49 U.S.C. § 1801 (1976), Congress provided for preemption on the reasonable ground that state and local regulations might otherwise lessen the degree of safety provided by uniform federal rules, or might interfere unreasonably with the unimpeded and safe flow of commerce. S.Rep.No.1192, 93d Cong., 2d Sess. 6-9, 37-38 (1974); see Hodel v. Virginia Surface Mining and Reclamation. Ass’n, supra, 101 S.Ct. at 2362; Ray v. Atlantic Richfield Co., 435 U.S. 151, 165-66; 98 S.Ct. 988, 998, 55 L.Ed.2d 179 (1978). Nothing in the Tenth Amendment to the Constitution undermines the validity of HMTA or of its preemption provision. As the Supreme Court recently said in Hodel v. Virginia Surface Mining and Reclamation Ass’n, supra, 101 S.Ct. at 2367-68, “the Tenth Amendment [does not limit] congressional power to pre-empt or displace state regulation of private activities affecting interstate commerce ... regardless of whether the federal legislation displaces laws enacted under the States’ ‘police powers.’ ” Moreover, HMTA does not impair Tenth Amendment rights recognized in National League of Cities v. Usery, 426 U.S. 833, 96 S.Ct. 2465, 49 L.Ed.2d 245 (1976). It neither “regulates the ‘States as States,’ ” nor “addresses matters that are indisputably ‘attributes of state sovereignty,’ ” nor impairs the ability of states “ ‘to structure integral operations in areas of traditional functions.’ ” Hodel v. Virginia Surface Mining and Reclamation Ass’n, supra, 101 S.Ct. at 2366 (quoting National League of Cities v. Usery, supra, 426 U.S. at 845, 852, 854, 96 S.Ct. at 2471, 2474, 2475). Indeed, [t]he regulation of traffic on roads and highways, with its strong regional and interstate character (particularly in the New York City metropolitan area), has long been considered to be a cooperative effort between City, State and federal authorities, with no single entity being able to provide or impose a comprehensive traffic system, and with federal power, where necessary, taking precedence. Friends of the Earth v. Carey, 552 F.2d 25, 38 (2d Cir.), cert. denied, 434 U.S. 902, 98 S.Ct. 296, 54 L.Ed.2d 188 (1977) (citations omitted). C. DOT’s Authority to Regulate the Transportation of Radioactive Materials New York State argues broadly that DOT has exceeded its authority under HMTA by regulating so as to permit the freer transport of a hazardous substance, without a finding of increased safety. HMTA’s declared policy is to increase the authority of the Secretary of Transportation “to protect the Nation adequately against the risks to life and property which are inherent in the transportation of hazardous materials in commerce.” 49 U.S.C. § 1801 (1976) (emphasis added). Radioactive materials have been designated “hazardous,” in that their transportation in commerce “may pose an unreasonable risk to health and safety or property.” Id. § 1802(2); see 49 C.F.R. § 171.8 (1980). And the Secretary’s power to issue regulations is expressed in terms of enhancing “the safe transportation in commerce of hazardous materials” and of governing “any safety aspect of” such transportation. 49 U.S.C. § 1804(a) (1976) (emphasis added). From these premises the State argues that DOT may not lawfully deem the transport of “hazardous” radioactive material to be safe, or preempt a local rule regulating the transport of material deemed “hazardous” without finding that the local rule renders such transport less safe than DOT’s rule. DOT’s authority cannot be so artificially limited. HMTA specifically authorizes regulations governing all aspects of the transportation of radioactive materials, including routing. Id. § 1804(a). Congress therefore contemplated that routing rules could advance HMTA’s goal of protecting the public. Furthermore, the designation of a material as hazardous does not necessarily establish that its transport under a particular regulatory scheme is hazardous. DOT could reasonably conclude under the Act that a particular method and route for transporting such a material in fact creates no significant hazard. DOT is also well within its authority to increase risks in one area or on one route, if it acts reasonably to establish an overall scheme for the safe and efficient transport of hazardous materials. In the present rulemaking DOT concluded that the interests of safety and efficiency required it to establish a national plan for transporting radioactive materials to stem and offset the proliferation of state and local rules. 46 Fed.Reg. at 5299. The Final Rule is in general thus reasonably within DOT’s authority. The State also challenges DOT’s assertion that the Final Rule was needed to enhance safety or efficiency. In fact, DOT’s Environmental Assessment concludes that, even if DOT had taken no action, the consequences would be “speculative.” City Motion, Ex. II at 25. The Assessment anticipates more local rules, but recognizes that “[t]hose impacts could involve both increases and decreases in accident risk and normal dose.” Id. at 9. Furthermore, with respect to efficiency, the Assessment could only report that the no-action costs “could be substantial” if by 1985, for example, localities enact restrictions so as to increase travel distances and times by 25%. Id. No estimates were made, however, “because of the uncertain nature of future state and local actions.” Id. The State’s analysis is acute, in that it supports the argument that DOT’s concern has been to facilitate transport by preventing state and local interference irrespective of their speculative costs and possible enhancement of safety. But the attack is so broad that it would leave too little latitude to a national regulatory body’s judgment on the need for uniformity and certainty. The DOT is vested by Congress with responsibility not only to deal with existing problems but also to deal with problems it reasonably concludes might arise. The record contains an ample basis for DOT’s perceptions that the existing multiplicity of laws presents dangers both to efficiency and to safety. Finally, and most concretely, the Final Rule does not merely override state and local rules. It also adopts many measures that are expressly and incontrovertibly designed to enhance safety, including, for example, enhanced driver training and protection against theft or sabotage. DOT takes pains to establish that the Final Rule will facilitate the shipment not only of spent fuel but also of small-quantity medical supplies, which it finds has been obstructed. See 46 Fed.Reg. at 5299. The State’s broad attack on DOT’s regulatory authority is therefore rejected. D. Effect of HMTA’s Preemption Provisions on DOT’s Authority Section 112(a) of HMTA provides for blanket preemption of nonfederal requirements inconsistent with validly promulgated federal rules, “[ejxcept as provided in subsection (b).” 49 U.S.C. § 1811(a) (1976). Section 112(b) permits the Secretary of Transportation to waive preemption for a nonfederal rule that protects the public at least as well as the inconsistent federal requirement and does not unreasonably burden commerce. Id. § 1811(b). In setting up this two-part preemption structure, Congress intended that states and localities would retain some role in the regulation of hazardous-materials transportation but that, once valid federal regulations were issued, inconsistent nonfederal requirements would be preempted unless the Secretary of Transportation grants a waiver. The City correctly assumes that only a valid federal regulation can have any preemptive effect. In fact, insofar as DOT’s Final Rule is found invalid in this proceeding, it has no preemptive effect on the City’s regulation. The City’s regulation may, however, apply to some shipments of radioactive materials that could not conceivably cause a high-consequence accident. Other state or local regulations may also apply to aspects of radioactive-materials transport that are validly regulated by DOT. To the extent the City or other nonfederal entities have regulations that are inconsistent with valid aspects of DOT’s Final Rule, they are unenforceable until and unless they are authoritatively deemed nonpreempted. The City and State argue that, even to the extent the Final Rule is valid, it cannot be given preemptive effect over a state or local law that in fact affords equal or greater protection to the public without unreasonably burdening commerce. They refer particularly to the language of section 112(b), which provides that an inconsistent nonfederal requirement “is not preempted if, upon the application of an appropriate State agency, the Secretary determines” that the requirement meets the specified criteria. Id. § 1811(b). Under this view, a nonfederal rule would be preempted only after DOT had found that it failed to meet the criteria of § 112(b). DOT would have to pass on every particular rule asserted to meet the § 112(b) tests; it could not deem entire groups of such rules inconsistent with its regulations, and thereby render them unenforceable, as it purports to have done in Appendix A of its Final Rule. These arguments are refuted by the language of HMTA, by its legislative history, and by the practical necessities of the regulatory process. The statutory language of § 112 expressly contemplates both an application for nonpreemption by the non-federal authority and a determination of nonpreemption by the Secretary before preemption is avoided. The nonfederal requirement may in fact provide greater public safety than the federal requirement and may in fact impose no unreasonable burden on commerce. But the statute says that the nonfederal rule is preempted if it is inconsistent, unless a nonpreemption ruling is obtained. It follows that, where no application for a nonpreemption ruling has been made with respect to an inconsistent non-federal rule, it is unenforceable. Nor is the mere application by a state or local authority for a nonpreemption ruling enough to permit enforcement of a nonfederal rule properly found to be inconsistent. Where Congress has intended to permit nonfederal regulations to stand until a federal authority has ruled otherwise, it has expressly said so. Compare, e.g., 15 U.S.C. § 1693q (Supp. II 1978) (Electronic Fund Transfer Act (EFTA) supplements laws of any state relating to electronic fund transfers, except to extent that those laws are inconsistent with EFTA; state law is not inconsistent with EFTA if it affords consumers greater protection; and Federal Reserve Board, upon request of interested party, shall “determine whether a State requirement is inconsistent or affords greater protection”). The legislative history of Congress’ adoption of HMTA’s preemption provision also indicates that an inconsistent nonfederal rule is unenforceable until completion of the § 112(b) process. The nonpreemption provision originated in the Senate and was adopted by the Conference Committee. See S.Rep.No.1347, 93 Cong., 2d Sess. 25 (1974), U.S.Code Cong. & Admin.News 1974, p. 7669. The Senate Committee on Commerce described its intention in adopting the provision as follows: This section sets out the general guidelines for how this bill, and regulations promulgated under it, are to interact with certain other Federal laws and with the laws of States and other political subdivisions. The Committee endorses the principle of Federal preemption in order to preclude a multiplicity of State and local regulations and the potential for varying as well as conflicting regulations in the area of hazardous materials transportation. However, the Committee is aware that certain exceptional circumstances may necessitate immediate action to secure more stringent regulations. For the purpose of meeting such emergency situations, the Committee has provided that any State or political subdivision may request, and the Secretary may grant, approval of regulations which vary from Federal regulations, provided that they are equivalent or more stringent and place no burden on interstate commerce. Subsection (a) sets out the general rule that conflicting laws of States and other political subdivisions are preempted. Subsection (b) sets up the mechanism by which a State or other political subdivision can apply to avoid preemption upon a showing that the regulation in question provides protection that is equal to or better than that provided by the Federal regulation. S.Rep.No.1192, 93d Cong., 2d Sess. 37-38 (1974). To read section 112 as permitting a nonfederal authority to treat an inconsistent rule as effective prior to obtaining a waiver from DOT would be inconsistent with the Senate Committee’s expressed understanding. The Committee contemplated that the “general rule” was preemption and that nonpreemption would occur because “exceptional circumstances may necessitate immediate action.” Even in “such emergency situations,” Congress did not provide for a nonfederal decision; rather, it stated that the Secretary “may” grant non-preemption on “a showing that the regulation in question provides protection that is equal to or better than that provided by the Federal regulation.” The City’s reading of section 112, moreover, would be inconsistent with Congress’ intention “to preclude a multiplicity of State and local regulations and the potential for varying as well as conflicting regulations in the area of hazardous materials transportation.” Id. HMTA provides explicitly for the preemption of nonfederal requirements inconsistent with validly promulgated federal regulations because Congress believed that substantial uniformity in the rules governing the transportation of hazardous materials is an important means of pursuing the statutory objectives of protecting both public safety and the unimpeded flow of- interstate commerce. Permitting nonfederal rules to remain in effect until DOT refuses to grant nonpreemption rulings would require DOT to pass on requests for waivers from every jurisdiction that applied for a ruling before being able effectively to enforce federal rules. Because extensive analysis is required before a proper ruling on a nonpreemption application, such a duty might severely undermine DOT’s capacity to regulate effectively. Plaintiffs also argue that DOT may not in advance deem entire categories or types of nonfederal rules inconsistent with a federal regulation. They attack DOT’s authority to adopt Appendix A to 49 C.F.R. Part 177, which expressly determines, among other things, tha