ELR Citation: ELR 21130
No(s). 95-5282 (D.C. Cir. May 10, 1996)

The court upholds the U.S. Environmental Protection Agency's (EPA's) interpretation of Emergency Planning and Community Right-to-Know Act (EPCRA) §302 as allowing the continued inclusion of isophorone diisocryanate (IPDI) on EPCRA's list of extremely hazardous substances (EHS) based solely on toxicity, and holds that EPA's refusal to delist IPDI was not arbitrary and capricious under the Administrative Procedure Act (APA), 5 U.S.C. §706(2)(A). The court first holds that EPCRA §302 does not speak clearly to whether toxicity can be used as the sole criterion for revising the EHS list. According to EPCRA §302, any revisions to the EHS list "shall take into account" a substance's toxicity, reactivity, volatility, dispersability, combustibility, or flammability. The fact that Congress used the disjunctive connective "or" suggests strongly that it did not intend to require EPA to consider all of the §302 factors when making revision decisions. On the other hand, the use of the phrase "shall take into account" to introduce the list of factors might be read to imply that EPA's discretion to consider only those factors it deems relevant is limited. Thus, the court turns to whether EPA's "toxicity-only" approach represents a permissible construction of EPCRA §302. Given its use alongside a disjunctive list, the phrase "shall take into account" can be reasonably interpreted as limiting EPA's authority to consider additional factors in making EHS list revisions rather than mandating that EPA consider every factor listed in §302. The court further holds that EP's interpretation is not impermissible because the Agency considers only one factor, toxicity, in all cases. EPA's toxicity-only approach accommodates the statutory scheme of EPCRA and serves the statutory purpose of encouraging the development of emergency plans to control off-site exposure to hazardous substances. Thus, the court holds that the toxicity-only approach used to deny the petition to remove IPDI from the EHS list represents a permissible construction because it accords with the language, structure, and purpose of EPCRA §302.

The court further holds that EPA's decision to deny the petition to delist IPDI was not arbitrary and capricious. The petitioner contended that EPA's decision was arbitrary and capricious because EPA used artifically high-concentration aerosol tests instead of the normal vapor tests to measure acute toxicity via inhalation. Despite the extreme conditions of the IPDI aerosol tests, the court holds that EPA acted reasonably when it ignored testing conditions in determining which chemicals should be classified as acutely toxic, because IPDI is toxic at low levels compared to other chemicals. The court also holds that the validity of extrapolating IPDI aerosol data to IPDI vapor represents the type of technical question that merits deference to the expertise of EPA. This case can be distinguished from cases where EPA relied on unrealistic assumptions when more accurate information is available. Because IPDI's toxicity can only be measured using higher concentraitons of IPDI in aerosol form, the court holds that EPA's reliance on aerosol tests to establish inhalation toxicity was not arbitrary and capricious. The petitioner also contended that EPA's failure to remove IPDI from the EHS list was arbitrary and capricious because IPDI's nontoxic physical and chemical properties render it overall a very low risk insofar as off-site exposure is concerned. The court holds that while EPA's discussion of the evidence on IPDI's physical and chemical properties was of less than ideal clarity, its comments are sufficient to discern its raitonale for denying delisting.

[The district court's opinion is published at 25 ELR 21503.]

Counsel for Appellant
William K. Rawson
Latham & Watkins
1001 Pennsylvania Ave. NW, Ste. 1300, Washington DC 20004
(202) 637-2200

Counsel for Appellees
Ellen J. Durkee
Environment and Natural Resources Division
U.S. Department of Justice, Washington DC 20530
(202) 514-2000

Before: WALD, GINSBURG, and HENDERSON, Circuit Judges.