Opinion ID: 718186
Heading Depth: 2
Heading Rank: 2

Heading: Application of the EPA's Interpretation of Section 302 to IPDI

Text: 22 An agency violates the Administrative Procedure Act if its application of a statute is arbitrary and capricious in a particular context, even if this application is based on a permissible construction of the statute. See 5 U.S.C. § 706(2)(A); Chemical Mfrs. Ass'n v. EPA, 28 F.3d 1259, 1265 (D.C.Cir.1994); Edison Elec. Inst. v. U.S.E.P.A., 2 F.3d 438, 446 (D.C.Cir.1993). Inquiry under the arbitrary and capricious standard is narrow; we review only to ensure that the agency examine[d] the relevant data and articulate[d] a satisfactory explanation for its action and will not substitute [our] judgment for that of the agency. Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43, 103 S.Ct. 2856, 2866, 77 L.Ed.2d 443 (1983). In addition, we will give an extreme degree of deference to the agency when it is evaluating scientific data within its technical expertise. International Fabricare Inst. v. U.S.E.P.A., 972 F.2d 384, 389 (D.C.Cir.1992); see also Marsh v. Oregon Natural Resources Council, 490 U.S. 360, 377, 109 S.Ct. 1851, 1861, 104 L.Ed.2d 377 (1989). 23 Huls offers two arguments as to why application of the EPA's general approach to delisting under section 302 is arbitrary and capricious in regard to IPDI. Huls first challenges the classification of IPDI as extremely hazardous based upon the aerosol tests, on the grounds that these tests used artificially high concentrations of IPDI and that conclusions regarding exposure to IPDI in an aerosol form are in no way indicative of the effects of exposure to IPDI vapor. The characterization of IPDI as acutely toxic based on tests with concentration levels well beyond IPDI's saturated vapor concentration might seem counterintuitive, but the EPA offers a reasoned explanation for this approach. In its denial of Huls' petition the EPA noted that toxicity tests commonly subject animals to conditions not likely to be replicated in reality. See Petition Denial, 59 Fed.Reg. at 51,819. As many commentators have discussed, the effects of low level exposure to a chemical may not be apparent from a test that involves a small number of animals but it is too expensive and cumbersome to test the large number of animals necessary to accurately determine these low level effects. Instead, animals are exposed to chemicals at artificially high levels and dose-response models are used to extrapolate the risk associated with more realistic levels of exposure. See, e.g., ROBERT V. PERCIVAL ET AL., ENVIRONMENTAL REGULATION: LAW, SCIENCE, AND POLICY 485-86 (1992); David D. Doniger, Federal Regulation of Vinyl Chloride: A Short Course in the Law and Policy of Toxic Substances Control, 7 ECOL.L.Q. 500, 512-14 (1978). This court previously upheld the EPA's use of data on the toxic effects associated with high exposure to conclude that any exposure may produce toxic effects. See Environmental Defense Fund v. EPA, 598 F.2d 62, 87 n. 95 (D.C.Cir.1978) (supporting the use of high exposure studies of PCBs in determining that any exposure to PCBs could pose a risk). 24 Consequently, much of the toxicity data on different chemicals may be derived from tests employing extreme exposures, and it was reasonable for the EPA to ignore testing conditions when determining which chemicals should be classified as acutely toxic. The extreme conditions of the aerosol tests of IPDI do not change [t]he fact ... that IPDI is toxic at low levels ... compared to other chemicals. Petition Denial, 59 Fed.Reg. at 51,819. 10 Huls argues that the fact that extreme exposures are generally used in toxicity testing does not justify the EPA's reliance on the aerosol tests, because toxicity tests usually involve high concentrations of substances in vapor form. Huls maintains that no conclusions regarding IPDI vapor can be drawn from the aerosol tests because of the difficulty involved in extrapolating across physical states. But the validity of such an extrapolation represents the type of technical question that we believe merits deference to the expertise of the EPA. See Environmental Defense Fund, 598 F.2d at 83-84 (EPA, not the court, has the technical expertise to decide what inferences may be drawn from the characteristics of related substances). 25 In addition, this case can be distinguished from other situations where we have found the EPA's regulation of substances to be arbitrary because the EPA relied on unrealistic assumptions. This is not a case where the EPA is choosing to rely on unrealistic data when more accurate information is available. See, e.g., Leather Indus. of America, Inc. v. EPA, 40 F.3d 392, 403 (D.C.Cir.1994) (EPA's reliance on assumptions arbitrary where record contained contradictory information). IPDI has a very low vapor pressure and a correspondingly low saturated vapor concentration. At this saturated vapor concentration IPDI does not produce demonstrable toxic effects. A measure of IPDI's toxicity can only be obtained by using higher concentrations of IPDI, and given IPDI's low vapor pressure, creating higher concentrations necessitates using IPDI in aerosol form. Furthermore, the record suggests that aerosol IPDI potentially could be released at toxic levels. Huls acknowledged that toxic levels of aerosol IPDI theoretically might be created if an explosion occurred next to IPDI material, but maintained that such an event was extremely unlikely. See Petition, JA 9. Although the EPA did not refer to the possibility of aerosol exposure resulting from an explosion, it appears from the petition denial that the EPA believed exposure to aerosol IPDI to be conceivable. The EPA specifically noted Huls' claim that creating IPDI aerosol requires unusual measures and characterized Huls' argument as being that the [aerosol] test ... subjects animals to extreme conditions not likely to be found in reality. Petition Denial, 59 Fed.Reg. at 51,819 (emphasis added). We therefore conclude that the EPA's reliance on aerosol tests of IPDI to establish IPDI's inhalation toxicity was not arbitrary and capricious, even though these tests utilize artificially high concentrations of IPDI and involve aerosol IPDI instead of IPDI vapor. 26 Huls also claims that the EPA's decision to deny delisting is arbitrary and capricious because, even granting that IPDI is acutely toxic, the other physical and chemical properties of IPDI render it overall a very low risk insofar as off-site exposure is concerned. The information submitted by Huls demonstrates that IPDI is not volatile or flammable and has a low reactivity with water. This evidence indicates that IPDI would be unlikely to become airborne and disperse if an accidental release of IPDI were to occur. Notably, however, this evidence does not contradict the EPA's finding that IPDI is an acutely toxic substance because it has an LC sub50 of 0.26 mg/l over a four hour period. In the petition denial, the EPA explained that it believed that the data on IPDI's toxicity was sound and that it was denying delisting primarily because IPDI was a highly toxic substance. See Petition Denial, 59 Fed.Reg. at 51,819. Although the EPA unfortunately did not elaborate much further, this statement does emphasize that a significant health hazard for the surrounding community might exist if off-site exposure did occur, no matter how remote the possibility. 27 In the petition denial, the EPA frequently referred to the description of the EHS listing methodology in the interim and final rules. See id. at 51,816-17, 51,819. The final rule offers a justification for not considering the physical and chemical properties of substances in determining whether to remove a substance from the EHS list: 28 Physical and chemical properties of substances ... are not used as criteria for listing because each chemical could be handled at non-ambient conditions. Because of the very variable conditions, the Agency believes it is appropriate to deal with factors such as ability to disperse and physical/chemical properties on a site-specific basis. 29 Final Rule, 52 Fed.Reg. at 13,388. 11 In the introduction to the petition denial the EPA repeated that the potential hazard represented by an EHS list substance chemical depends on how it is used: 30 [t]he identification of a chemical that meets the EHS criteria does not in itself indicate the potential for serious effects in any release.... Rather, such identification indicates a need for the community to undertake a program to investigate and evaluate the potential for accidental exposure associated with the production, storage or handling of the chemical at a particular site. 31 Petition Denial, 59 Fed.Reg. at 51,816. Again, the EPA's explanation is too cryptic for our tastes; yet we can understand the EPA to be discounting Huls' claim that off-site exposure of IPDI was extremely unlikely because the possibility of such exposure might increase with different conditions. 32 Finally, Huls' reliance on Chemical Manufacturer's Association and Edison Electric Institute is misplaced. Those cases involved instances where the record was barren of any rational relationship between the methodology used by the EPA to set regulatory levels and the known behavior of the substance to which this methodology was applied. See, e.g., Chemical Mfrs. Ass'n, 28 F.3d at 1265-66 (EPA's use of generic air dispersion model to set emissions levels was arbitrary where unrebutted evidence in the record indicated that substance did not behave as model assumed); Edison Elec. Inst., 2 F.3d at 446 (no factual support indicating that waste mismanagement scenario envisioned by EPA was even plausible). Here, the EPA used data on the physical and chemical properties of IPDI in calculating the TPQ, and it is the TPQ that triggers the significant regulatory action under section 302. The fact that the EPA increased the TPQ for IPDI in response to the data contained in the petition demonstrates that the EPA did not ignore the known properties of IPDI. 33 While the EPA's discussion of the evidence on IPDI's physical and chemical properties is certainly of less than ideal clarity, its comments are sufficient for us to discern its rationale for denying delisting. Bowman Transp. Inc. v. Arkansas-Best Freight Sys., Inc., 419 U.S. 281, 286, 95 S.Ct. 438, 442, 42 L.Ed.2d 447 (1974); see also Atlantic Tele-Network, Inc. v. FCC, 59 F.3d 1384, 1390-91 (D.C.Cir.1995) (agency rationale still discernible even though agency did not address each of the petitioner's arguments). The EPA found that IPDI had been correctly classified as an acutely toxic substance and that off-site exposure of IPDI was conceivable, depending on the conditions at which IPDI is handled at a particular site. Thus, we find that the EPA's decision to deny delisting of IPDI was not arbitrary and capricious.