Respondent McKinney, a Nevada state prisoner, filed suit against petitioner prison officials, claiming that his involuntary exposure to environmental tobacco smoke (ETS) from his cellmates and other inmates cigarettes posed an unreasonable risk to his health, thus subjecting him to cruel and unusual punishment in violation of the Eighth Amendment. A federal magistrate granted petitioners motion for a directed verdict, but the Court of Appeals reversed in part, holding that McKinney should have been permitted to prove that his ETS exposure was sufficient to constitute an unreasonable danger to his future health. It reaffirmed its decision after this Court remanded for further consideration in light of Wilson v. Seiter, 501 U.S. 294, in which the Court held that Eighth Amendment claims arising from confinement conditions not formally imposed as a sentence for a crime require proof of a subjective component, and that, where the claim alleges inhumane confinement conditions or failure to attend to a prisoners medical needs, the standard for that state of