, concurring in part and dissenting in part:
I agree with the majority opinion that the injunction should be vacated to the extent it orders the state to maintain the heat index below 88 degrees. However, because, as the majority opinion recognizes, “the rest of the injunction does not exceed the Ball I mandate,” I would affirm it. The relief measures ordered, including IcyBreeze units and diverted cool air, are consistent with the less-intrusive remedies suggested in Ball 1 and extend no further than necessary to correct plaintiffs’ constitutional injury. ’
I write briefly to explain my view of the role of the mandate rule in this case. In its application of the mandate rule, the majority opinion reverses the district court’s order despite concluding that most of the relief ordered “does not exceed the Ball I mandate.” It reasons that the district court erred by “[rjelying on a maximum, heat index”—even though the injunction does not generally mandate one—because “Ball I plainly foreclosed any consideration of a maximum heat index.”
But in Ball I, our court was clear that “[t]he district court did not abuse its discretion by admitting evidence of or relying on the heat index.” Ball v. LeBlana (Ball I), 792 F.3d 584, 591 (5th Cir. 2015) (emphasis’ added). And for good reason. The heat; index is the unit of measure consistently used in the medical and scientific literature to measure and identify the risk of heat-related illness. See id.; Ball v. LeBlanc, 223 F.Supp.3d 529, 537 (M.D. La. 2016). To forbid the district court from considering a maximum safe heat index is to require that court to remedy the constitutional violation that we have found exists, see Ball I, 792 F.3d at 596, without considering its cause. The record evidence, credited by the district court and not substantively challenged on appeal, demonstrates that these medically compromised plaintiffs face a risk of serious Harm when they are exposed to heat indices above 88 degrees. See Ball, 223 F.Supp.3d at 536-37. That factual finding must be considered when the district court assesses whether any heat-remediation plan is sufficient to remedy plaintiffs’ Eighth Amendment injury.1 See Graves v. Arpaio, 623 F.3d 1043, 1049-50 (9th Cir. 2010) (affirming injunction requiring sheriff to house pretrial detainees taking psychotropic medications in temperatures that do not exceed 85 degrees based on finding that exposure to higher temperatures presents an unreasonable risk of harm).
Of course, if the district court truly did conclude that the Second Plan was inadequate simply because it failed to maintain a heat index below 88 degrees, that might in practice be the same as mandating a maximum heat index and thus violate our court’s Ball I mandate (absent relevant new evidence). See United States v. Matthews, 312 F.3d 652, 657 (5th Cir. 2002) (stating that mandate rule requires lower court to implement “both the letter and the spirit of the appellate court’s mandate” (quoting United States v. Becerra, 155 F.3d 740, 753 (5th Cir. 1998))). But the district court concluded that the Second Plan was inadequate because of plaintiffs’ testimony that they “continued to experience heat-related symptoms during the implementation of Defendants’ Second Plan” and expert testimony that cool showers, ice, and fans, without more, did not eliminate the substantial risk of serious harm that these plaintiffs face from extreme heat. Ball, 223 F.Supp.3d at 536-37, 544-45. To be sure, the district court further concluded, based on the testimony of plaintiffs’ expert, that “[t]he only means to reduce the substantial risk of serious harm to Plaintiffs, and thereby remedy the Eighth Amendment violation in this case, is to lower the temperatures and heat indi-ces to which Plaintiffs are exposed.” Id. at 545. But, in a facility where the heat index frequently exceeds 100 degrees and has risen as high as 110.3 degrees, id. at 531— 32, requiring the state to lower the heat indices to which these medically compromised plaintiffs are exposed is not the same as mandating that the heat index remain below 88 degrees. It is only the latter that (absent relevant new evidence) Ball I forbids.
Contrary to the majority opinion’s assertion, Ball I did not foreclose relitigating on remand whether a maximum heat index, or any other form of relief, could be necessary to remedy these plaintiffs’ constitutional injury. By explicitly noting that “Gates upheld an injunction providing narrower relief’ and that there was “no showing that the Constitution mandated more relief for these prisoners for the same prison condition in this case,” 792 F.3d at 600, Ball I contemplated the possibility that new evidence could require other— possibly broader—relief.2 That was for good reason. Injunctions must be open to modification in tight of new facts or changed circumstances. See Brown v. Plata, 563 U.S. 493, 542-43, 131 S.Ct. 1910, 179 L.Ed.2d 969 (2011) (“A court that invokes equity’s power to remedy a constitutional violation by an injunction mandating systemic changes to an institution has the continuing duty and responsibility to assess the efficacy and consequences of its order. ... [A] court must remain open to a showing ... that the injunction should be altered to ensure that the rights and interests of the parties are given all due and necessary protection.”). No mandate can change that. See Baum v. Blue Moon Ventures, LLC, 513 F.3d 181, 190 (5th Cir. 2008) (stating, in context of a law-of-the-case challenge, that “[mjodification of an injunction is appropriate when the legal or factual circumstances justifying the injunction have changed” (quoting ICEE Distribs., Inc. v. J&J Snack Foods Corp., 445 F.3d 841, 850 (5th Cir. 2006))); Amado v. Microsoft Corp., 517 F.3d 1353, 1360 (Fed. Cir. 2008) (stating that the mandate rule “does not preclude the district court from ■modifying, or dissolving, the injunction if it determines that it is no longer equitable”); Matthews, 312 F.3d at 657 (stating that the law of the case doctrine, which includes the mandate rule, “merely expresses the practice of courts generally to refuse to reopen what has been decided, [it is] not a limit to their power” (quoting Messenger v. Anderson, 225 U.S. 436, 444, 32 S.Ct. 739, 56 L.Ed. 1152 (1912))).
While it is true, as the majority opinion notes, that the new-evidence exception to the mandate rule is inapplicable to issues squarely foreclosed by a previous appeal, whether a different remedy could be necessary under unaddressed new facts is not an issue that can be squarely foreclosed. Ball I held only that the evidence then in the record was insufficient to establish the necessity of facility-wide air conditioning and/or a maximum heat index of 88 degrees. To suggest, as I think the majority opinion does, that Ball Ts record-specific holding forecloses future litigation of the necessity of those remedies is to imply that the mandate rule restricts a district court’s authority, and indeed duty, to modify an injunction in light of changed circumstances. But that is contrary to established law. See, e.g., Baum, 513 F.3d at 190.
The static quality that I fear the majority’s opinion may inject into our Eighth Amendment jurisprudence is also inconsistent with the nature of Eighth Amendment rights. Gates does not set a ceiling for permissible heat-relief measures in prisons. “No statie ‘test’ can exist by which courts determine whether conditions of confinement are cruel and unusual, for the Eighth Amendment ‘must draw its meaning from the evolving standards of decency that mark the progress of a maturing society.’” Rhodes v. Chapman, 452 U.S. 337, 346, 101 S.Ct. 2392, 69 L.Ed.2d 59 (1981) (quoting Trop v. Dulles, 356 U.S. 86, 101, 78 S.Ct. 590, 2 L.Ed.2d 630 (1958) (plurality opinion)). Whether conditions of confinement amount to an Eighth Amendment violation necessarily depends on the context-specific “totality of ' the circumstances.” Id. at 362-63, 101 S.Ct. 2392. Courts must be free to consider those circumstances, as they change, and in tight of evolving standards of decency, when determining what relief the Eighth Amendment requires.
Because there was no new evidence submitted relevant to the -necessity of an 88 degree maximum heat index, I would vacate just that single provision of the injunction mandating such a maximum heat index. The rest of the injunction, orderihg remedies previously approved of. by us, is consistent with Ball I and the PLRA, particularly given the evidence presented that the Gates remedies alone were insufficient to remedy plaintiffs' constitutional injuries. I would therefore affirm it.
. This is not to say that a constitutionally sufficient heat-remediation plan must maintain a heat index below 88 degrees. The district court found that the risk of serious harm due to heat "significantly increases when an individual is exposed to heat indices of 88-degrees or greater.” Ball, 223 F.Supp. at 537. But the Eighth Amendment does not protect against any and -all risk of harm; rather, it protects against “extreme” conditions, Hudson v. McMillian, 503 U.S. 1, 9, 112 S.Ct. 995, 117 L.Ed.2d 156 (1992), that present an “unreasonable risk” of harm, Helling v. McKinney, 509 U.S. 25, 35, 113 S.Ct. 2475, 125 L.Ed.2d 22 (1993). Determining whether "conditions of confinement violate the Eighth Amendment requires more than a scientific and statistical inquiry into the seriousness of the potential harm and the likelihood that such injury to health will actually be caused.” Id. at 36, 113 S.Ct. 2475. Determining the relevant level of risk "also requires a court to assess whether society considers the risk that the prisoner complains of to be so grave that it violates contemporary standards of decency to expose anyone unwillingly to such a risk.” Id. In other words, that there is some risk of harm when the heat index exceeds 88 degrees does not necessarily mean that the Eighth Amendment requires a heat index below that number.
. The majority opinion states that Ball I "closed the door to air conditioning as a permissible remedy here.” I agree, but only because plaintiffs did not produce any sub-stanfively new evidence demonstrating that air conditioning—in the sense of mechanical cooling—is necessary to remedy their constitutional injuries. However, I disagree to the extent that the majority opinion suggests that Ball I closed the door to air conditioning regardless of any new evidence presented. I read Ball I to narrowly say that air conditioning was not a permissible remedy absent evidence that the more modest measures approved of in Gates were insufficient for these plaintiffs. In Yates v. Collier, 868 F.3d 354 (5th Cir.2017), two of our colleagues from the Ball I panel confirmed that “Ball [I] held that air-conditioning was not appropriate in that case because other acceptable and less-intrusive remedies had yet to be tried—not that air-conditioning was necessarily an impermissible remedy.” Id. at 370. Yates is a clarification of, and consistent with, Ball I. See 792 F.3d at 600 (noting absence of evidence that plaintiffs in this case require more extensive relief than plaintiffs in Gates). Furthermore, as the majority opinion recognizes, some form of cooled air—-be it from an IcyBreeze unit or diverted cool, i.e., air-conditioned, air—can be a permissible remedy.