Opinion ID: 744479
Heading Depth: 3
Heading Rank: 2

Heading: Polychlorinated alkanes

Text: 63 The EPA listed a category of chemicals called polychlorinated alkanes. A polychlorinated alkane consists of chains of hydrogen, carbon and chlorine atoms and is obtained through the partial chlorination of paraffin, olefin, or acetylene feedstock. The EPA restricted the category to shortchain polychlorinated alkanes, meaning those with carbon chain lengths of 10 to 13 carbon atoms (C sub10 , C sub11 , C sub12 , and C sub13 ). The EPA also restricted the category based on the number of chlorine atoms and the average chlorine content. Within these parameters, the EPA included polychlorinated alkanes manufactured from each of the different feedstock, although the EPA's listing decision relied exclusively on studies of polychlorinated alkanes manufactured from paraffins. Based on these studies, the EPA determined that polychlorinated alkanes can be anticipated to cause serious chronic health effects and significant adverse effects on the environment. See 42 U.S.C. § 11023(d)(2)(B), (C). 64 CMA challenges the rule on the ground that the data relating to chlorinated paraffins cannot support the listing of alpha-olefins, that is, alkanes derived from olefin feedstock. When a polychlorinated alkane is manufactured from the chlorination of a paraffin it contains compounds with varying carbon chain lengths; the chains may have 10 carbon atoms (C sub10 ), eleven carbon atoms (C sub11 ), etc. Chlorinated alphaolefins, by contrast, are composed almost entirely of chains with twelve carbon atoms (C sub12 ). CMA complains that the EPA improperly relied on studies of chlorinated paraffins without independently testing the C sub12 fraction of the chlorinated paraffin mixture, and that there is no evidence that the C sub12 components are responsible for the observed toxicity. 65 The EPA maintains that the chlorination of paraffins and [alpha-olefins] results in products that do not differ significantly structurally, physically, or toxicologically. 59 Fed.Reg. 61,432, 61,461. In support, the EPA compares the structure of a polychlorinated alkane derived from an olefin to the structure of a polychlorinated alkane derived from a paraffin. The distinguishing feature between an alkane and an olefin is the double bond between the first two carbon atoms in an olefin. When the olefin is chlorinated, the chlorine atoms attach at the double bond and change the double bond to a single bond, thereby changing the olefin to an alkane and making it indistinguishable from the polychlorinated alkane derived from the paraffin. As a result, 66 an [alpha-olefin] and a paraffin, both with the same chain length and both with the same degree of chlorination, are essentially identical structurally (especially if the degree of chlorination is high); the same isomers can be predicted for the chlorination of an [alpha-olefin] and a paraffin of the same chain length. The physical properties of chlorinated [alpha-olefins] and the corresponding chlorinated paraffins are therefore expected to be very similar. 67 Id. at 61,463. 68 As we have stated, the EPA was entitled to list a category of chemicals based on its reasonable determination that a member of the category caused a relevant ill effect and that other members of the category could be expected to exhibit the same characteristics. In the case of polychlorinated alkanes, the EPA has adequately defended its conclusion that alpha-olefins can be expected to exhibit the same toxic characteristics as chlorinated paraffins. These judgments cannot be challenged except with substantial and weighty evidence to the contrary. In the absence of such evidence, we give considerable deference to the EPA's technical judgment. Huls America Inc. v. Browner, 83 F.3d 445, 453 (D.C.Cir.1996). We hold that the EPA has presented sufficient evidence for its decision to list polychlorinated alkanes.