United States Court of Appeals

for the Fifth Circuit

No. 19-20723

Corey Prantil; Ronald Whatley; Betty Whatley; Bret 

Simmons; Phyllis Simmons; Greg Nason; Larry 

Anderson; Tanya Anderson; Keith Lyons; Beverly 

Flannel; Roland Flannel, 

Plaintiffs—Appellees,

versus

Arkema Incorporated, 

Defendant—Appellant.

Appeal from the United States District Court 

for the Southern District of Texas 

USDC No. 4:17-CV-2960

Before Higginbotham, Elrod, and Haynes, Circuit Judges.

Patrick E. Higginbotham, Circuit Judge:

As Hurricane Harvey deluged southeastern Texas with record floods, 

volatile chemicals at a facility in Crosby, Texas, combusted, releasing toxic 

ash and smoke into the surrounding communities and causing the evacuation 

of nearby residents. Seeking redress for the physical and financial effects of 

the incident, certain Crosby-area property owners brought a class action 

against the facility’s owner—Arkema, Inc.—on behalf of themselves and 

United States Court of Appeals

Fifth Circuit

FILED

January 22, 2021

Lyle W. Cayce

Clerk

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2

their neighbors. Arkema appeals from an order granting class certification. 

We vacate the district court’s certification order and remand the case for 

further proceedings under Rule 23.

I.

Arkema’s facility in Crosby, Texas, produces Luperox, a liquid 

organic peroxide used to make plastics and composites. Luperox is a volatile 

compound that decomposes and combusts unless refrigerated. The Crosby 

facility sits in a flood plain near the Gulf Coast, leaving it vulnerable to the 

approach of Hurricane Harvey. By August 24, 2017, it was clear that Harvey 

would make landfall and likely stall over Texas. Arkema continued 

production at Crosby until August 25, 2017, before implementing the 

facility’s hurricane preparedness plan. Several days of heavy rain and rising 

flood waters at Crosby forced the facility’s “ride-out” team to move nearly 

350,000 pounds of combustible materials to refrigerated trailers set on higher 

ground. But the floodwaters’ continued rise eventually threatened the 

trailers’ cooling systems as well, and on August 29, 2017, Arkema alerted 

local authorities that a combustion event was imminent. The authorities 

responded by establishing a 1.5-mile evacuation zone around the facility. 

Between August 31 and September 4, nine refrigerated trailers burned in 

three separate ignitions, the last of which was a controlled burn by emergency 

personnel. Further, two of the facility’s wastewater tanks overflowed,

dispersing contaminated water and bringing the count to five total emissions 

events. Shortly afterward, local residents saw clouds of white smoke and 

accumulating ash on their properties, and persons inside and outside of the 

established 1.5-mile evacuation zone reported physical symptoms including 

bodily rashes, headaches, eye irritation, blisters, and respiratory difficulty.

Plaintiffs are local property owners who seek to represent a class of all 

property owners within a seven-mile radius of the Crosby facility to pursue 

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injunctive relief and damages against Arkema. They claim to have suffered 

adverse health effects, property damage, or both, because of Arkema’s 

emissions. They bring claims against Arkema under the Resource 

Conservation and Recovery Act (RCRA), the Comprehensive 

Environmental Response, Compensation, and Liability Act (CERCLA), and 

the common-law doctrines of negligence, trespass, and public nuisance.

After extended oral argument on Plaintiffs’ motion for class 

certification and Akrema’s motions to exclude certain experts, the district 

court granted Arkema’s motion to exclude Plaintiffs’ damages expert, but it 

credited three of Plaintiffs’ experts and granted Plaintiffs’ motion for class

certification.

1 In granting certification, the district court held that the 

proposed class met the elements of Federal Rule of Civil Procedure 23(a) and 

that it should be certified as a damages class under Rule 23(b)(3) because 

common issues would predominate in the resolution of the class claims and 

that a class action was the superior method for adjudicating the dispute.

2 The

district court also certified an injunctive-relief class under Rule 23(b)(2) 

because the “actions alleged apply broadly to the entire class, and the 

injunctive relief sought will commonly address this injury.”3 We granted 

leave to appeal on October 17, 2019.

Arkema urges four arguments on appeal: (1) that the district court did 

not conduct the rigorous analysis required by Fifth Circuit and Supreme 

Court precedent, to ensure that the individual claims can be fairly and 

effectively adjudicated in a class action; (2) that the district court erred when 

1 Prantil v. Arkema, No. 17-2960 at 39 (S.D. Tex. June 3, 2019) (order granting class 

certification).

2 Id. at 19-27, 29-39.

3 Id. at 28.

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it determined that the proposed class met Rule 23(b)(3)’s predominance 

requirement and Rule 23(b)(2)’s cohesiveness requirement; (3) that the 

benefits realized by classwide adjudication of common questions would be 

lost in the necessary sifting through individualized evidence on the causation

and injury elements in addition to the intractably individualized nature of the 

damages and injunction inquiries; and (4) that the district court erred by 

relying on certain expert opinions in its certification decision without first 

ensuring those opinions would be admissible at trial under the Daubert

standard.

II.

We review the district court’s decision to certify a class for abuse of 

discretion.4 Although a district court has broad discretion to certify a class, it 

must “rigorously analyze Rule 23’s prerequisites” before doing so.5 Such 

analysis requires “the district court to go beyond the pleadings to determine 

whether the requirements of Rule 23 have been met: ‘a court must 

understand the claims, defenses, relevant facts, and applicable substantive 

law in order to make a meaningful determination of the certification 

issues.’”6 Additionally, the district court must consider “how a trial on the 

merits would be conducted” if the class were certified.7

We begin with the standard applicable to expert evidence at the classcertification stage. We then address the predominance of common questions 

4 Crutchfield v. Sewerage & Water Bd. of New Orleans, 829 F.3d 370, 375 (5th Cir. 

2016).

5 Spence v. Glock, G.m.b.H., 227 F.3d 308, 310 (5th Cir. 2000).

6 Cole v. Gen. Motors Corp., 484 F.3d 717, 724 (5th Cir.2007) (quoting Castano v. 

Am. Tobacco Co., 84 F.3d 734, 745 (5th Cir. 1996)).

7 Castano v. Am. Tobacco Co., 84 F.3d 734, 740 (5th Cir. 1996).

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in the Rule 23(b)(3) damages class and the cohesiveness of the Rule 23(b)(2) 

injunctive-relief class.

A. Daubert’s Applicability to Class Certification

Since its early days, Rule 23 with its b(2) and b(3) classes has played 

an increasingly important role in addressing the challenges of aggregating 

large numbers of persons seeking recompense for a single event or for injuries 

suffered from a common set of facts—product failures, myriad disasters at 

the hand of man and nature. With all its difficulties in application, the class 

device has proven to be a powerful workhorse to the benefit of plaintiffs and 

defendants so as now to be essential. 

Yet, certification changes the risks of litigation often in dramatic 

fashion.8 Thus, under Rule 23(f), we have the discretion to hear interlocutory 

appeals of class certification orders.9 This rule was a response to the 

determinative character of the certification decision and a perceived need for 

developing a jurisprudence of federal class actions across substantive lines in 

conformity with the Enabling Act.10 The Supreme Court in turn developed a 

mootness doctrine that treated certification of a class as the determinant—

loss of the class representative did not moot a certified class.

11 In short, these 

responses to the consequential character of class certification frames the 

8 See Blair v. Equifax Check Servs., Inc., 181 F.3d 832, 834 (7th Cir. 1999) (“[A]

denial of class status can doom the plaintiff,” while “a grant of class status can put 

considerable pressure on the defendant to settle.”).

9 Fed. R. Civ. P. 23(f).

10 Advisory Committee’s 1998 Note on subd. (f) of Fed. Rule Civ. Proc. 23.

11 See Genesis Healthcare Corp. v. Symczyk, 569 U.S. 66, 75–76 (2013) (explaining 

that under Sosna v. Iowa, 419 U.S. 393 (1975) and United States Parole Comm’n v. 

Geraghty, 445 U.S. 388 (1980), “a putative class acquires an independent legal status once 

it is certified under Rule 23”).

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question of the quality of evidence its rests upon. And, we ask, when the 

cementing of relationships among proffered class members of liability or 

damages or both turns on scientific evidence should we insist that the metric 

of admissibility be the same for certification and trial. We answer that 

question in the affirmative; the Daubert hurdle must be cleared when 

scientific evidence is relevant to the decision to certify.

In so holding, we join three other federal courts of appeal.

12 The Third 

Circuit’s reasoning on this issue in In re Blood Reagents Antitrust Litigation, is 

particularly instructive, drawing as it does on recent Supreme Court 

precedent.

13 The Third Circuit saw the need to apply Daubert at the 

certification stage as a natural extension of the Supreme Court’s admonition 

in Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338, 351 (2011), and Comcast Corp. 

v. Behrend, 569 U.S. 27, 35 (2013), to conduct a “rigorous analysis” of the 

proposed class’s conformity with Rule 23.14 In Dukes, the Supreme Court 

expressed “doubt” that “Daubert did not apply to expert testimony at the 

certification stage of class-action proceedings.”15 And in Comcast, which 

concerned use of an expert’s damages model to certify an antitrust class 

action, the Supreme Court reaffirmed that it is incumbent on plaintiffs to 

submit “evidentiary proof” of their compliance with Rule 23.

16 As the Third 

Circuit observed, “[e]xpert testimony that is insufficiently reliable to satisfy 

the Daubert standard cannot ‘prove’ that the Rule 23(a) prerequisites have 

12 In re Blood Reagents Antitrust Litig., 783 F.3d 183, 187 (3d Cir. 2015); Sher v. 

Raytheon Co., 419 F. App’x 887, 890–91 (11th Cir. 2011); Am. Honda Motor Co. v. Allen, 600 

F.3d 813, 816 (7th Cir. 2010).

13 783 F.3d 183 (3d Cir. 2015).

14 Id. at 187.

15 564 U.S. at 354.

16 569 U.S. at 33–34.

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been met ‘in fact,’ nor can it establish ‘through evidentiary proof’ that Rule 

23(b) is satisfied.”17 This is consistent with our prior holding that the class 

“certification inquiry . . . must be made based on adequate admissible 

evidence to justify class certification.”18 Thus, if an expert’s opinion would 

not be admissible at trial, it should not pave the way for certifying a proposed 

class.

Plaintiffs do not take issue with this reasoning; they do not contend 

that case law or practical considerations militate against using Daubert for 

class certification. Instead, they contend that Arkema has no grounds for 

complaint here because the district court applied a full-bore Daubert analysis 

when it assessed Plaintiffs’ experts. Our able district judge here was sensitive 

to the concerns presented by expert evidence. He heard arguments on each 

of Arkema’s motions, and granted one, excluding Plaintiffs’ damages expert 

“because he has not actually built or tested any regression analyses that he 

suggests could be appropriate for determining damages on a class-wide 

basis.”19 The district court did not disregard its gate-keeping role, but its 

analysis of the expert reports reflect hesitation to apply Daubert’s reliability 

standard with full force. 

The district court began its discussion of the expert reports by 

observing that “[w]hether a full Daubert analysis at the class certification 

stage is required is unclear.”20 When discussing Plaintiffs’ evidence of 

chemical contamination, the district court observed that “[w]hile it certainly 

would have been better for Dr. Kaltofen additionally to include the 

17 In re Blood Reagents, 783 F.3d at 187.

18 Unger v. Amedisys Inc., 401 F.3d 316, 319 (5th Cir. 2005).

19 Prantil, No. 17-2960 at 15.

20 Id. at 6.

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background levels, it was not necessary under Daubert at the class 

certification stage,”21 implying that Daubert is less applicable to evidence 

used for certification. In its certification order, the district court was not as 

searching in its assessment of the expert reports’ reliability as it would have 

been outside the certification setting. We do not suggest that the remaining 

reports should be excluded; some of Arkema’s objections may only affect the 

weight of the reports without undermining their fundamental reliability. In 

sum, an assessment of the reliability of Plaintiffs’ scientific evidence for 

certification cannot be deferred.

B. The Predominance of Questions Common to the Damages 

Class

The district court determined that the proposed damages class was 

suitable for certification under Rule 23(b)(3), which provides that a class 

action can be maintained if Rule 23(a) is satisfied, if “questions of law or fact 

common to class members predominate over any questions affecting only 

individual members, and [if] a class action is superior to other available 

methods for fairly and efficiently adjudicating the controversy.”22 Arkema 

does not dispute that the proposed class meets Rule 23(a)’s threshold 

requirements or that a class action is the superior litigation vehicle.23 This 

leaves the issue of predominance.

The predominance requirement “tests whether proposed classes are 

sufficiently cohesive to warrant adjudication by representation.”24 It “calls 

21 Id. at 12.

22 Fed. R. Civ. P. 23(b)(3).

23 Prantil, No. 17-2960 at 18-27 (finding that the class satisfies the requirements of 

numerosity, commonality, typicality, adequacy, and ascertainability).

24 Torres v. S.G.E. Mgmt., L.L.C., 838 F.3d 629, 636 (5th Cir. 2016) (en banc) 

(quoting Amchem Prods., Inc. v. Windsor, 521 U.S. 591, 623 (1997)).

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upon courts to give careful scrutiny to the relation between common and 

individual questions in a case.”25 Predominance is a “far more demanding” 

hurdle than Rule 23(a)’s commonality requirement.26 

Courts should consider predominance on a claim-by-claim basis,27 and 

the district court did so here: for negligence, it found duty and breach to be 

common issues;28 for trespass, the question of unlawful entry was common 

to the class;29 for public nuisance, the question of unreasonable interference 

was common.

30 Similarly, the district court concluded that all three elements 

of Plaintiffs’ RCRA claim presented common questions. 31 As for CERCLA, 

25 Tyson Foods, Inc. v. Bouaphakeo, 136 S. Ct. 1036, 1045 (2016). “An individual 

question is one where ‘members of a proposed class will need to present evidence that 

varies from member to member,’ while a common question is one where ‘the same 

evidence will suffice for each member to make a prima facie showing [or] the issue is 

susceptible to generalized, class-wide proof.’” Id. (alteration in original) (quoting 

2 William B. Rubenstein, Newberg on Class Actions § 4:50 (5th ed.

2012)).

26 Amchem Prods., Inc., 521 U.S. at 623–24.

27 Castano, 84 F.3d at 744.

28 Prantil, No. 17-2960 at 31.

29 Id. at 31-32. For a claim of trespass to real property, the plaintiff must show 

ownership or a right to possess property; physical, intentional, and voluntary entrance by 

the defendant; and injury. Wilen v. Falkenstein, 191 S.W.3d 791, 798 (Tex. Ct. App.—Fort 

Worth 2006, pet. denied).

30 Prantil, No. 17-2960 at 32. The elements of a public nuisance claim are an 

“unreasonable interference with a right common to the general public” and a “special 

injury” that is “distinct from the injury to the public at large.” Peiqing Cong v. 

ConocoPhillips Co., 250 F. Supp. 3d 229, 233 (S.D. Tex. 2016).

31 Prantil, No. 17-2960 at 33. To bring an RCRA claim, the plaintiff must show “(1) 

that the defendant is a person, including, but not limited to, one who was or is a generator 

or transporter of solid or hazardous waste or one who was or is an owner or operator of a 

solid or hazardous waste treatment, storage, or disposal facility; (2) that the defendant has 

contributed to or is contributing to the handling, storage, treatment, transportation, or 

disposal of solid or hazardous waste; and (3) that the solid or hazardous waste may present 

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the district court found that three issues—Arkema’s status as a qualifying 

responsible person, the Crosby site’s status as a qualifying facility, and the 

occurrence of a hazardous release—were common.32 

The district court then addressed whether Plaintiffs’ alleged damages, 

the diminution in their property values, would entail individual inquiries 

outweighing the common inquiries relating to liability. Plaintiffs proposed to 

calculate classwide damages through mass property appraisals, but the 

district court rejected the report of Plaintiffs’ damages expert because he 

failed to offer a reliable means of making these calculations. Neither the court 

nor Plaintiffs identified another means by which Plaintiffs could calculate 

damages on a classwide basis. Nonetheless, the district court found that 

common legal and factual questions still predominated because “‘virtually 

every issue prior to damages is a common issue,’” and Plaintiffs proposed to 

bifurcate the proceedings so that damages could be addressed separately, if 

at all.33

The district court identified elements of each claim that would present 

common questions, but its predominance inquiry then paused. With that 

pause, the district court’s approach resembles that taken by the district court 

an imminent and substantial endangerment to health or the environment.” Cox v. City of 

Dallas, 256 F.3d 281, 292 (5th Cir. 2001).

32 Prantil, No. 17-2960 at 33-34. A CERCLA plaintiff must show “(1) that the site 

in question is a ‘facility’ as defined in [42 U.S.C.] § 9601(9); (2) that the defendant is a 

responsible person under [42 U.S.C.] § 9607(a); (3) that a release or a threatened release 

of a hazardous substance has occurred; and (4) that the release or threatened release has 

caused the plaintiff to incur response costs.” Vine St. LLC v. Borg Warner Corp., 776 F.3d 

312, 315 (5th Cir. 2015).

33 Prantil, No. 17-2960 at 37 (quoting Bertulli v. Ind. Ass’n of Continental Pilots, 242 

F.3d 290, 298 (5th Cir. 2001)).

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in Madison v. Chalmette.

34 In Madison, the district court certified a class of 

individuals who sought damages for exposure to a refinery’s emission of coke 

dust while attending a reenactment of the Battle of New Orleans. The district 

court concluded that class certification was appropriate because “there is one 

set of operative facts that [will] determine liability[:] Plaintiffs were either on 

the battlefield and exposed to the coke dust or they were not.”35 We vacated 

the order because, despite the appealing simplicity of its formulation, “[t]he 

district court did not meaningfully consider how Plaintiffs’ claims would be 

tried.”36 The inadequacy of the district court’s predominance inquiry was 

due, in part, to its failure to account for issues implicated by the asserted 

claims and defenses, issues turning on potentially nuanced determinations of

plaintiffs’ “location, exposure, dose, susceptibility to illness, nature of 

symptoms, type and cost of medical treatment, and subsequent impact of 

illnesses on individuals.”37 Although we did “not suggest that class 

treatment [was] necessarily inappropriate,” we vacated the certification 

order and remanded the case because the lack of “‘analysis or discussion 

regarding how [the district court] would administer the trial’” was an abuse 

of discretion.38

Here, as in Madison, the district court’s certification order did not 

discuss the considerations affecting the administration of trial, and it 

concluded that common questions would predominate without adequately 

addressing Arkema’s arguments that causation, injury, and damages would 

34 637 F.3d 551 (5th Cir. 2011).

35 Id. at 556.

36 Id.

37 Id. at 557.

38 Id. at 556–57 (quoting Robinson v. Tex. Auto. Dealers Ass’n, 387 F.3d 416, 425–26 

(5th Cir. 2004)).

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be highly individualized. The district court’s discussion of trial 

administration was limited to observing that it was amenable to Plaintiffs’

proposal to bifurcate the trial of liability and damages. But it did not discuss 

the manner in which it would conduct the liability phase or how it would 

implement Plaintiffs’ proposed “bellwether trials” at the damages phase.

Although the district court acknowledged that Plaintiffs’ mass appraisal 

approach to property damages was untenable after their expert was 

disqualified, it did not discuss how this difficulty might affect an eventual 

damages phase in the proceedings. The district court recognized that 

individualized damages do not make the case per se unsuitable for class 

treatment,39 and then concluded that any issues could be addressed as they 

arose. In so doing, the court drifted to the “figure-it-out-as-we-go-along” 

approach, one to be avoided.

40 

When considering the propriety of class certification, the district 

court must “respond to the defendants’ legitimate protests of individualized 

issues that could preclude class treatment.”41 This is part of the district 

court’s obligation to “understand the claims [and] defenses” at play.42 A 

39 See, e.g., In re Deepwater Horizon, 739 F.3d 790, 815–16 (5th Cir. 2014) (“[I]t is 

indeed possible to satisfy the predominance ... requirements of Rule 23(b)(3) in a mass tort 

or mass accident class action despite the particular need in such cases for individualized 

damages calculations.” (internal quotations omitted)).

40 Madison, 637 F.3d at 557.

41 Chavez v. Plan Ben. Servs., Inc., 957 F.3d 542, 546 (5th Cir. 2020) (citing M.D. ex 

rel. Stukenberg v. Perry, 675 F.3d 832, 842-43 (5th Cir. 2012) (noting that “[t]he district 

court clearly rejected” the defendant’s individualization argument but had not 

“sufficiently analyzed” it)).

42 Castano, 84 F.3d at 745.

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certification order ought to reflect the district court’s consideration of a 

defendant’s weightiest arguments against certification.43

We find that the certification order is wanting in its answer to 

Arekma’s arguments that a trial of class claims would devolve into 

individualized inquiries on causation, injury, and damages. For instance, the 

district court rejected Arkema’s contention that causation would become too 

individualized by reasoning that because “Plaintiffs focus only on chemicals 

with a strong link to the facility explosion, there are fewer hyper-localized 

alternative sources that would turn proof of causation into a series of minitrials. . . . [and] alternative causes would likely apply to large chunks or all of 

the class area.”44 The basis for this conclusion that few alternative sources 

need be considered is unclear. Other parts of the order suggest that the 

district court may have relied on Plaintiffs’ expert, Dr. Kaltofen, to conclude 

that alternative sources for the chemicals in question would not be an issue. 

But the order also states that Dr. Kaltofen addressed only “some of these 

alternative sources and ruled them out in his rebuttal report.”45 The 

difficulty is that we are uncertain whether alternative sources will be a factor

at trial and whether these alternative sources can be dealt with in groups, as 

the district court suggested. 

The district court also held that injury resulting from Arkema’s 

alleged negligence, trespass, etc. could be proven on a classwide basis because 

“individuals’ exposure to contaminants results not just from contaminants 

43 See, e.g., Chavez, 957 F.3d at 549 (reversing a class certification where the district 

court responds to “warring factual contentions” concerning putatively common issues, 

with a “thin survey” and “unsupported assurance” as explanations for why predominance 

is satisfied).

44 Prantil, No. 17-2960 at 31.

45 Id. at 14 (emphasis added).

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on their properties, but from community-wide contaminants that individuals 

are exposed to as they go about their daily lives in the area.”46 This reasoning 

has a welcome, commonsense appeal, but “Rule 23 requires the court to 

‘find,’ not [] assume, the facts favoring class certification.”47 The issue is 

whether the record contains scientific evidence supporting the conclusion 

that the movements of class members could result in exposure sufficient to 

cause cognizable harm.

48 An assumption about the movement of persons 

throughout the class area cannot relieve Plaintiffs of their burden to

“‘affirmatively demonstrate [their] compliance with [] Rule [23].’”49 And by 

itself, the assumption does not allay the concern that proof of causation and 

harm could vary greatly from one class member to another based on the 

location of their property and the extent and frequency of their movements 

within the class area. 

Much of the district court’s predominance analysis proceeded from 

its view that “all injuries resulted from [a] single course of conduct,” and 

thus “the focus will be on Defendant’s actions.”50 Of course, a case may be 

relatively more suitable for class treatment where only one defendant and one 

course of conduct are at issue.

51 But what is needed here is discussion of how 

proof of Arkema’s conduct will affect trial.52 Absent such analysis, we are 

46 Id. at 26-27.

47 Unger, 401 F.3d at 321.

48 “[C]ourts must certify class actions based on proof, not presumptions.” Flecha 

v. Medicredit, Inc., 946 F.3d 762, 768 (5th Cir. 2020).

49 Id. at 766–67 (quoting Dukes, 564 U.S. at 350).

50 Prantil, No. 17-2960 at 32. 

51 See, e.g., Crutchfield, 829 F.3d at 378 (listing cases).

52 See Gene & Gene LLC v. BioPay LLC, 541 F.3d 318, 326 (5th Cir. 2008) (“The 

district court did not explain how the common course of conduct it described would affect 

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unable to judge whether the common issues relating to Arkema’s conduct in 

the leadup to Hurricane Harvey are relatively more complex such that they 

can be expected to predominate over individualized issues.53 Future 

certification proceedings would here benefit from detailing the evidence the 

parties may use to prove or defend against liability and its commonality to all 

class members.

We do not exhaustively catalogue the matters deserving consideration 

under Rule 23(b)(3) on remand. And we do not suggest that Arkema is 

entitled to prevail on its counterarguments to certification. We hold only that 

the relative balance of concededly common claim elements to contested 

elements of causation and injury warrants closer attention.

C. The Cohesiveness of the Injunctive-Relief Class

Plaintiffs seek two separate forms of injunctive relief from Arkema: 

medical monitoring and property remediation. Rule 23(b)(2) provides that a 

class action may be maintained if “the party opposing the class has acted or 

refused to act on grounds that apply generally to the class, so that final 

injunctive relief or corresponding declaratory relief is appropriate respecting

the class as a whole[.]”54 “It is well-established that ‘[i]nstead of requiring 

common issues, [Rule] 23(b)(2) requires common behavior by the defendant 

a trial on the merits. Thus, the district court’s assertion that this case would not degenerate 

into a series of individual trials is largely unsupported and is, in our opinion, mistaken.”).

53 Cf. Steering Comm. v. Exxon Mobil Corp., 461 F.3d 598, 603 (5th Cir. 2006) 

(“Based on the evidence presented to the district court regarding the complexity of the 

medical causation and damages issues, and with little evidence that the liability issues are 

similarly complex, it was not an abuse of its discretion for the district court to conclude that 

Appellants had failed to demonstrate that the class issue of Appellee’s negligence or strict 

liability predominates over the vastly more complex individual issues of medical causation 

and damages.”).

54 FED. R. CIV. P. 23(b)(2).

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toward the class.’”55 Thus, 23(b)(2) certification has three requirements: 

“(1) ‘class members must have been harmed in essentially the same way’; 

(2) ‘injunctive relief must predominate over monetary damage claims’; and 

(3) ‘the injunctive relief sought must be specific.’”56 “The specificity 

element requires plaintiffs to give content to the injunctive relief they seek so 

that final injunctive relief may be crafted to describe in reasonable detail the 

acts required.”57

The district court concluded that members of the proposed class had 

been harmed in essentially the same way because the injuries for which they 

seek injunctive relief arise from Arkema’s conduct in preparing for and 

mitigating the effects of Hurricane Harvey on its Crosby facility. Concerning 

Plaintiffs’ request for medical monitoring, the district court found that “[i]f 

their allegations are true, Plaintiffs need to be repeatedly tested for health 

effects so that cancer or other diseases may be caught early and treated,” and

“the injunctive relief sought will commonly address [Plaintiffs’] injury.”58

The district court envisioned the medical monitoring injunction as an

iterative process involving “early detection and treatment” through which

“a more complete understanding of the potential consequences of exposure 

is attained and treatment plans are put into place.”59 But the district court 

did not discussthe range or types of medical monitoring the injunction would 

implement.

55 Yates v. Collier, 868 F.3d 354, 366 (5th Cir. 2017) (quoting In re Rodriguez, 695 

F.3d 360, 365 (5th Cir. 2012)).

56 Id. (quoting Maldonado v. Ochsner Clinic Found., 493 F.3d 521, 524 (5th Cir. 

2007)).

57 Yates, 868 F.3d at 367 (internal quotations omitted)

58 Prantil, No. 17-2960 at 27.

59 Id. at 27-28.

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Concerning Plaintiffs’ request for property remediation, the district 

court explained that “a remediation program can be applied class-wide—

perhaps one that orders testing of Plaintiffs’ properties and cleanup of 

contaminants, as described” in the report of one of Plaintiffs’ experts, Dr. 

Glass.60 The district court observed that it was necessary to deal with 

remediation on a classwide basis because “[i]ndividual clean-up attempts 

would be ineffectual, [and] because landowners could still be exposed as they 

move throughout the class area.”61 Although it mentioned the possibility of 

implementing the testing program in Dr. Glass’s report, the district court 

made no specific findings as to what the property remediation program would 

entail.

These discussions of the injunctions in their broad strokes do not 

satisfy the requirement that injunctive relief be reasonably specific. Our 

decisions make clear that more is needed than a common failure by the 

defendant and the prospect that all class members could realize some benefit 

if the defendant is compelled to act or desist.62 To be sure, “Rule 23(b)(2) 

does not require that every jot and tittle of injunctive relief be spelled out at 

the class certification stage,” but some “‘reasonable detail’ as to the ‘acts 

required’” is necessary.63

We do not agree with Arkema that our decision in M.D. ex rel. 

Stukenberg v. Perry necessarily precludes all possible forms of injunctive relief 

for the proposed class. In Stukenberg, a proposed class of foster care children 

sought “at least twelve broad, classwide injunctions, which would require the 

60 Id. at 28.

61 Id.

62 Stukenberg, 675 F.3d at 846.

63 Yates, 868 F.3d at 368 (quoting Stukenberg, 675 F.3d at 848).

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district court to institute and oversee a complete overhaul of Texas’s foster 

care system.”64 Although we reversed the district court’s finding that the 

class was cohesive, we clarified that Rule 23(b)(2) does not require “a 

specific policy uniformly affecting—and injuring—each [plaintiff] . . . so long 

as declaratory or injunctive relief ‘settling the legality of the [defendant’s] 

behavior with respect to the class as a whole is appropriate.’”65 The 

proposed class in Stukenberg sought injunctive relief addressing years of 

varied neglect and requiring the district court to outsource responsibility for

determining the form of the injunctions to expert panels that would do the 

actual work of tailoring relief.

66

Here, by contrast, there is stronger evidence that through its response 

to a specific event, Hurricane Harvey, Arkema “acted or refused to act on 

grounds that apply generally to the class.”67 The current record does not 

compel the conclusion that Plaintiffs’ medical and property injuries are 

incapable of being addressed by classwide injunctions. For instance, it is not 

necessarily fatal to a uniform scheme of property remediation that certain 

properties may contain higher concentrations of contaminants than others,

provided Plaintiffs can identify a common method of remediation and some 

reasonable standard by which remediation might be assessed.68

64 Stukenberg, 675 F.3d at 845.

65 Id. at 847–48 (quoting Fed. R. Civ. P. 23(b)(2) 1966 Amendment advisory 

committee note).

66 Id. at 846-47.

67 Fed. R. Civ. P. 23(b)(2)

68 Cf. Yates, 868 F.3d at 368 (requested injunction deemed reasonably specific for 

class certification where plaintiffs “identified air-conditioning as a remedy that would 

provide relief to each member of the class” and identified “maintaining a heat index of 88 

degrees or lower” as the applicable standard). 

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Still,we are sensitive to the challenges inherent in crafting appropriate

injunctions. As Arkema notes, there is some uncertainty as to what symptoms 

or conditions will be medically monitored for all class members, whether

individual health considerations need to be addressed for relief to be 

adequate. Concerning property, the certification order leaves us uncertain as 

to how the extent of necessary property remediation can be determined, and 

whether a responsive injunction can be fashioned to account for Arkema’s 

past remediation efforts. If the district court intends to wholly adopt one or 

another proposal from Plaintiffs’ experts, it must say so and explain how that 

proposal overcomes Arkema’s concerns.69 Despite the present uncertainty 

concerning the propriety of classwide injunctive relief, we are confident that 

by evaluating the particulars of each injunction on remand, both the parties 

and the district court will arrive at a nuanced assessment of whether 

Plaintiffs’ claims for relief can be effectively addressed in a class action.70

III.

We do not here limit the tools necessary to the district court’s

management of complex litigation, such as the oft-deployed bifurcation of 

liability and damages. The reality of Rule 23 is that it depends upon the 

69 Cf. Maldonado, 493 F.3d at 524 (plaintiffs could not seek classwide injunctive 

relief under 23(b)(2) requiring defendant to provide “mutually affordable healthcare” 

when plaintiffs “failed [] to identify any way to determine what a reasonable or ‘mutually 

affordable’ rate [was] for the wide variety of medical services offered”).

70 See id. (“The difficulty in specifying exactly what Appellants seek from an 

injunction highlights the fact that individualized issues here overwhelm class 

cohesiveness.”).

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management skills of our able district courts. We only set the boundaries of 

the field on which their discretion is applied.

We vacate the district court’s order certifying the proposed class and 

remand the case for further proceedings including certification of the class.

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