Cite as: 515 U. S. 687 (1995)
O'Connor, J., concurring
Proximate causation is not a concept susceptible of precise definition. See Keeton, supra, at 280-281. It is easy enough, of course, to identify the extremes. The farmer whose fertilizer is lifted by a tornado from tilled fields and deposited miles away in a wildlife refuge cannot, by any stretch of the term, be considered the proximate cause of death or injury to protected species occasioned thereby. At the same time, the landowner who drains a pond on his property, killing endangered fish in the process, would likely satisfy any formulation of the principle. We have recently said that proximate causation "normally eliminates the bizarre," Jerome B. Grubart, Inc. v. Great Lakes Dredge & Dock Co., 513 U. S. 527, 536 (1995), and have noted its "functionally equivalent" alternative characterizations in terms of foreseeability, see Milwaukee & St. Paul R. Co. v. Kellogg, 94 U. S. 469, 475 (1877) ("natural and probable consequence"), and duty, see Palsgraf v. Long Island R. Co., 248 N. Y. 339, 162 N. E. 99 (1928). Consolidated Rail Corporation v. Gott-shall, 512 U. S. 532, 546 (1994). Proximate causation depends to a great extent on considerations of the fairness of imposing liability for remote consequences. The task of determining whether proximate causation exists in the limitless fact patterns sure to arise is best left to lower courts. But I note, at the least, that proximate cause principles inject a foreseeability element into the statute, and hence, the regulation, that would appear to alleviate some of the problems noted by the dissent. See, e. g., post, at 719 (describing "a farmer who tills his field and causes erosion that makes silt run into a nearby river which depletes oxygen and thereby [injures] protected fish").
In my view, then, the "harm" regulation applies where significant habitat modification, by impairing essential behaviors, proximately (foreseeably) causes actual death or injury to identifiable animals that are protected under the Endangered Species Act. Pursuant to my interpretation, Palila II--under which the Court of Appeals held that a state
713
Page: Index Previous 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 NextLast modified: October 4, 2007