Opinion ID: 744479
Heading Depth: 3
Heading Rank: 1

Heading: Diisocyanates category

Text: 55 Isophorone diisocyanate (IPDI), 2,2,4 trimethylhexamethylene diisocyanate (2,2,4 TMDI) and 2,4,4 trimethylhexamethylene diisocyanate (2,4,4 TMDI) were listed on the TRI as part of a category of chemicals known as the diisocyanates category. The EPA listed the category, which contains twenty chemicals, under subheading (B) based on chronic pulmonary toxicity observed in studies of six of the chemicals. CMA argues that the statute does not permit the EPA to list chemical categories without demonstrating separately that each individual chemical meets the statutory criteria. 56 In order to prevail, CMA must show that the challenged agency decision is arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law. 5 U.S.C. § 706(2)(A). The final rule will be upheld so long as the agency has acted within its delegated statutory authority, considered all of the relevant factors, and demonstrated a reasonable connection between the facts on the record and its decision. Ethyl Corp. v. EPA, 51 F.3d 1053, 1064 (D.C.Cir.1995). In matters of statutory interpretation, the court first asks whether Congress has directly spoken to the precise question at issue. Chevron, 467 U.S. at 842, 104 S.Ct. at 2781. If so, the matter is settled, for the court, as well as the agency, must give effect to the unambiguously expressed intent of Congress. Id. at 842-43, 104 S.Ct. at 2781. [I]f the statute is silent or ambiguous with respect to the specific issue, the question for the court is whether the agency's answer is based on a permissible construction of the statute, id., meaning one that is reasonable and consistent with the statute's purpose. Nuclear Information Resource Service v. NRC, 969 F.2d 1169, 1173 (D.C.Cir.1992). At that point, the court need only conclude that the agency's understanding of the statute is a sufficiently rational one to preclude a court from substituting its judgment for that of the agency. Chemical Mfrs. Ass'n v. NRDC, 470 U.S. 116, 125, 105 S.Ct. 1102, 1107-08, 84 L.Ed.2d 90 (1985). 57 As discussed above, EPCRA provides that [a] chemical may be added if ... there is sufficient evidence that the chemical is known to cause or can reasonably be anticipated to cause one of three effects. 42 U.S.C. § 11023(d)(2). In the absence of a statutory definition, the EPA defined chemical to mean an individual chemical or a category of chemicals. Based on this interpretation, the EPA determined that a category of chemicals may be added based on sufficient evidence that characteristics common to the category give rise to the effects. 58 It is not the case that the term chemical unambiguously excludes chemical categories. In fact, Congress itself used the word chemical to include categories of chemicals when it stated that the original TRI included those chemicals on the list in Committee Print Number 99-169 of the Senate Committee on Environment and Public Works. 42 U.S.C. § 11023(c). The list in Committee Print Number 99-169 included both individual chemicals and twenty chemical categories, including chlorophenols, glycol ethers, and thallium compounds. In light of the surrounding text, therefore, CMA cannot successfully challenge the EPA's interpretation under step one of Chevron. Moreover, we have no reason, considering the surrounding text, to require the agency to adopt CMA's interpretation of chemical at Chevron step two. To the extent that there is any ambiguity in the term, the EPA has put forth an eminently reasonable interpretation. We hold that the EPA may add chemical categories to the TRI without demonstrating separately that each individual chemical meets the statutory criteria. 59 CMA also challenges the listing decision on the grounds that there was insufficient evidence with regard to IPDI, 2,2,4-TMDI, and 2,4,4-TMDI because the EPA failed to take account of differences between diisocyanates. A diisocyanate compound is a molecule composed of two isocyanate groups, each consisting of a carbon atom double-bonded to both an oxygen atom and a nitrogen atom. Diisocyanates vary in their physical and chemical characteristics. A diisocyanate may be aromatic, meaning that each of the isocyanate structures is bonded to a benzene ring, or aliphatic, meaning that it has no benzene ring. Diisocyanates may be in liquid or solid form and exhibit a range of molecular weights and vapor pressures. Moreover, some diisocyanates have an isocyanate group para, meaning opposite, from the methyl group in a 6-carbon benzene ring that is thought to be highly reactive. The EPA believes that diisocyanates are appropriately added as a category because members of this category are structurally similar (i.e., each contains the diisocyanate functionality), they induce a similar toxic effect (chronic pulmonary irritation), and their toxicity is due to the diisocyanate portion of the molecule common to all members. 59 Fed.Reg. 61,432, 61,442. 60 The EPA's conclusion that toxicity is caused by the diisocyanate portion of the molecule, and so could reasonably be expected in IPDI, 2,2,4-TMDI, and 2,4,4-TMDI, is supported by the fact that the six studied chemicals exhibit the full range of the category's widely varying physical and chemical properties and each exhibits toxicity. Four of the observed chemicals are aromatic; the remaining two are aliphatic. The two aliphatic diisocyanates, by definition, do not have the highly reactive isocyanate group in the para position. Two of the six chemicals are solids; four are liquids. The chemicals also vary with respect to molecular weight and vapor pressure. In light of the chemicals' varied physical and chemical properties, it was reasonable for the EPA to attribute the pulmonary irritation to a common characteristic: the diisocyanate portion of the molecule. This determination is precisely the type of technical, scientific judgment this court will not second-guess. See Environmental Defense Fund v. EPA, 598 F.2d 62, 83-84 (D.C.Cir.1978) (EPA, not the court, has the technical expertise to decide what inferences may be drawn from the characteristics of related substances). 61 CMA also argues that the EPA ignored relevant evidence by declining to consider a four-week study that exposed male rats to IPDI in which the researchers did not find signs of pulmonary irritation. We disagree. The agency declined to credit the four-week study because it was short-term. Agency guidelines require that generally a study is not considered valid unless it is conducted for 90 days or longer. Guidelines at 29. In addition, the study did not clearly address pulmonary irritation. The EPA was not required to consider a study that did not clearly address the matter at issue. Portland Cement Ass'n v. Ruckelshaus, 486 F.2d 375, 394 (D.C.Cir.1973), cert. denied, 417 U.S. 921, 94 S.Ct. 2628, 41 L.Ed.2d 226 (1974) ([C]omments must be significant enough to step over a threshold requirement of materiality before any lack of agency response or consideration becomes of concern.). This is not a case in which the EPA has disregarded direct evidence for more speculative assumptions. 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). Instead, the agency reasonably determined that the study was inapposite. We, therefore, conclude that the EPA's decision to list IPDI, 2,2,4-TMDI, and 2,4,4-TMDI was consistent with the statute and supported by sufficient evidence. 62 CMA also challenges the agency's listing decision because, it claims, the agency failed to justify its determination that pulmonary irritation as observed in the diisocyanate studies is serious or irreversible as required by EPCRA. The EPA did not include statements in its rulemaking to the effect that pulmonary irritation is a serious health effect because breathing is an essential life activity. Such a statement was not required because the seriousness of the effects is self-evident. Appellants have raised similar challenges to the listing of four of the remaining chemicals. We find these challenges equally meritless. With regard to each chemical, the agency cited effects such as lesions in the liver, kidneys, and spleen 2,6--Dimethylphenol (DMP); severe gastrointestinal irritation 2-Bromo-2-nitropropane-1,3-diol (Bronopol); increased liver-to-body weight ratios and nonneoplastic pathological changes in the stomach 3-iodo-2-propynyl butyl carbamate (IPBC); and reductions in male fertility index and female fecundity index N-Methyl-2-pyrrolidone (NMP). The agency was not required to discuss in detail the seriousness of these effects.