### IN THE SUPREME COURT OF IOWA

No. 15

– 1942
Filed May 12 , 20 17

LAURIE FREEMAN, SHARON MOCKMORE, BECCY BOYSEL, GARY D. BOYSEL, LINDA L. GOREHAM, GARY R. GOREHAM, KELCEY BRACKETT , and BOBBIE LYNN WEATHERMAN , Appellees ,

vs.
GRAIN PROCESSING CORPORATION , Appellant

.

Appeal from the Iowa District Court for Muscatine County,
Thomas G. Reidel , Judge.

Defendant appeals district court ruling certifying case as a class
action. DISTRICT COURT CLAS S CERTIFICATION ORDER
AFFIRMED.

Michael R. Reck, Mark McCormick, Charles F. Becker, and Kelsey J. Knowles of Belin McCorm ick, P.C., Des Moines; Steven J. Havercamp and Eric M. Knoernschild of Stanley, Lande & Hunter, P.C., Muscatine; and Joshua B. Frank of Baker Botts L.L.P., Washington, D.C. , for appellant.

Sarah E. Siskind and Scott A. Entin of Miner, Barnhill & Galland, P.C., Madison, Wisconsin ; James C. Larew of Larew Law Office,
Iowa City; and Claire M. Diallo of Browne, Dial lo & Roy, LLP,
Princeton Junction, New Jersey, for appellee s
.2

WATERMAN , Justice. In this appeal, we must decide whether the district court abused its discretion by certifying this case as a class action. The plaintiffs are
residents of Muscatine , Iowa, who live near a corn wet milling plant. The plaintiffs allege air pollution from the plant interferes with the use of their property . They have filed this lawsuit alleging state common law and statutory claims based on nuisance, trespass , and negligence theories. In a prior appeal, we held th eir cl aims were not preempted by
the F ederal Clean Air Act (CAA). Freeman v. Grain Processing Corp. , 848 N.W.2d 58 , 94 (Iowa 2014). On remand, the district court, over defendant’s objections, granted the plaintiff s’ motion for class
certification and divided the class into two subclasses. For the reas ons explained below, we affirm the class certification order.
I. Background Facts and Proceedings. Grain Processing Corporation (GPC) has operated its corn wet milling facility in Muscatine since 1943 , convert ing corn kernels into products for commercial and industrial use. On April 23, 2012 , eight
Muscatine residents living near GPC filed a putative class action on behalf of “themselves and others who have res ided within one and one

half miles from the perimeter” of GPC’s facility within the preceding five
years , an estimated 4 000 residents

. T he ir petition provides this overview
of their claims:
Th e plaintiffs allege the corn wet milling operation at GPC’s facility creates hazardous by

- products and harmful chemicals, many of which are released directly into the atmosphere.

. . . They assert the polluting chemicals and particles are blown from the facility onto nearby properties. They note particulate matte r is visible on properties, yards, and grounds and various chemical pollutants are also present. Compounding these adverse effects, according to the plaintiffs, GPC has used, continues to use, and has failed to replace its worn and outdated technology wit h available3 technology that would eliminate or drastically reduce the pollution. The plaintiffs assert these emissions have caused them to suffer persistent irritations, discomforts, annoyances, inconveniences, and put them at risk for serious health effe cts.
Id. at 63

– 64. The plaintiffs limited their damage claims to loss of use and enjoyment of property, foregoing claims for diminution in value or personal injury

. GPC moved for summary judgment, asserting plaintiff s’ common law and statutory claims wer e preempted by the CAA and Iowa Code chapter 455B (2011) , Iowa’s counterpart to the CAA

. GPC’s motion alternatively argued the lawsuit raised nonjusticiable political questions.
The district court granted GPC’s motion for summary judgment based on
preemp tion and the political

- question doctrine. The district court relied on a key federal preemption decision that subsequently was reversed on appeal

. On our review, we concluded the plaintiffs’ claims were not preempted or barred by the political

- question doctrine. Id. at 83

– 85, 88

– 89, 93

– 94. W e reversed the summary judgment and re instated the
lawsuit against GPC , relying in part on th e new federal appellate decision
filed after the district court’s ruling

. See id. at 65 n.2 & 94

. We
remanded t he case to the district court.
A. Plaintiff s ’ Motion for Class Certification. The plaintiffs
moved for class certification after remand. GPC resisted class
certification on several grounds. T he plaintiffs argue d common questions of law and fact predominate d over individual claims

— a fundamental requirement for class certification

. Common questions
include d “whether GPC violated its duty of care, whether the haze, odor,
and smoke emitted from GPC [were] the product of negligence, and
whether such emissions constituted negligence or unlawful trespass.”
T he plaintiffs proposed a plan for adjudicating their claims . The plan4

focused on three prongs : GPC’s common course of conduct, proof of harm, and calculation of damages. First, the plaintiffs pro posed to show GPC’ s common course of conduct in knowingly creating a nuisance

. They pointed to i nternal
emails indicating GPC was aware of the pollution and the need to update equipment to improve air quality

. For example, i n 2008, Derek Biggs,
GPC’s plant manager, email ed coworkers observing, “At times when I was there, the parking lot and south end of Muscatine [were] covered in a haze, and if we had that odor, haze, etc. in Washington, we would have serious problems with the locals.” Mick Durham, G PC’s environmental
d irector, received an email in 2010 from Kurt Levetzow, an em ployee of
the Department of Natural Resources ( DNR) who stated he was “amazed at a bluish colored haze that was leaving GPC’s property and blanketing the residential neighborho od across from the plant.” A 2012 email from Bill Chrisman, GPC senior process e nginee r, to Durham disclosed that over one weekend the facility’s dryers caused “the neighborhood [to be] so smoky across the street that it was fairly hard to see, not to men tion
breathe.” GPC engineers described the dryers as “antiquated,” “deteriorating,” “run down,” and “older higher polluting.”
T he plaintiff s proposed to prove that GPC delayed fixing the problems by choosing to focus its resources elsewhere . T echnologi es to reduce emissions were available but not implemented at GPC’s Muscatine plant. The plaintiffs characterized this common proof as the “most sig nificant portion of the trial, ” stating, Whether it be a class case or an individual trial, there is going to be a lot of evidence, a significant amount of evidence regarding the culpability of GPC’s conduct. That evidence will be the same, over and over again, for every single class member. Regardless if this case is tried once or tried hundreds or thousands of time s , the same witnesses,5 the same documents will be testified about, the same issues [will be presented]

. The plaintiffs noted , “[T] hese conditions and GPC’s knowledge of them are facts and evidence that reside at the heart of every class member’s

c laims.”
In the second phase , the plaintiffs prop osed to focus on proof of
harm : that every resident within one

- and

- a

- half mile s suffered a
nuisance. T he plaintiffs would offer three categories of evidence. The
first addressed causation; it “revolve[d] around GPC’s public admissions that its operation had been causing the smoke, the odor and the haze that had concerned the Muscatine community for years

. ” The next addressed harms suffered by the residents. The plaintiffs proposed to offer testimony from twenty to thirty “ normal ” persons living
with in the class boundaries , describing the common character of the
harm. The plaintiffs submitted over 100 declarations from resident s. Most described the smell emitted from the GPC plant as “burned corn” or “rotten eggs.” Many mentioned dust

- like particles accumulating on their
lawns and homes. S ometimes the dust was white or gray, and
sometimes it was darker. Most declarations indicated t he smell or ash happened daily or nearly every day and mentioned symptoms of burning eyes and irritated sinuses. Many said they could not open windows or enjoy the outdoors due to the smell and dust. The plaintiffs alleged these
declarations , together wi th resident s’ testimony , met the objective
standard for nuisance : that normal persons in the community found the conditions offensive, annoying, or intolerable. The plaintiffs stated, Plaintiffs are prepared to present testimony from normal persons from all over the class area who regard GPC’s pollution as definitely offensive, seriously annoying or intolerable. Whether they are, in fact, normal persons living in the community will be a jury question. But if so, and if the jury credits their testimony, it will establish that GPC6 created a nuisance at their properties, and if in every portion of the class area normal persons testify that they experienced a nuisance, then it is permissible for a jury to infer that a nuisance has been suffered throughout th e class area.
GPC could then present conflicting testimony from other residents within
the class boundaries who did not experience similar harm or were not bothered by the emissions. The final type of evidence plaintiffs intended to offer was air
modelin g data from Dr. Paul Rosenfeld

. Dr. Rosenfeld plotted the dispersion of three types of emissions: volatile organic c ompounds (VOCs), particulate matter (PM10), and sulfur dioxide. T hese emissions were proxies for odor, smoke, and haze, respectively. Dr. Rosenfeld used AERMOD, an EPA

- approved modeling algorithm that accounts for wind direction, wind speed, temperature, humidity, precipitation, and certain obstructions to estimate where the wind blew particles from GPC.
Dr. Rosenfeld’s m odel revealed pollutant concentrations and variations over time across the class area. He also developed a “wind rose” analysis, based on the sixteen cardinal wind directions, which he used to quantify the amount of time each property received “direct hit s,” or was downwind from, the emissions. Dr. Rosenfeld’s data showed “the presence of the same pollutants frequently and repeatedly on every property in the class, and .

. . the presence of those pollutants at properties closely surrounding the properties of the testifying normal persons.” A t the class certification hearing , the plaintiffs’ counsel explained, And if you look at this, what you don’t see, Your Honor, is during the hour of 5:00 to 6:00 a.m., a single solitary orange little cloud only coverin g the red cross that is Ms. Mockmore’s property. What you do see is that when GPC’s soup of pollutants are blown at Ms. Mockmore’s property, all of the other parcels and properties in close7 proximity to Ms. Mockmore’s are similarly hit by GPC’s soup of po llutants. And the Mockmore’s property is not isolated in this observation, Your Honor. And this is important because this is why it supports the inference that we’re asking the jury to make in this case, that when Ms. Mockmore or this normal person or t hat normal person testifies about his or her experience with GPC’s pollutants . . . it is a reasonable inference for the jury to infer that similar properties in close proximity experience a similar nuisance[.] “All of this evidence in combination, these three categories of evidence,”
the plaintiffs argued, “will support a reasonable inference by the jury that the nuisance conditions existed on every property in the class area.” Finally, for the third phase of the plaintiff’s proposed trial strategy , th e plaintiff s suggested a form ula for calculating damages. Initially , the y proposed using a sim ple per diem formula, in which the jury w ould

assess a per

- hour amount ( $10 to $15) for the time each resident lived in
the area. A lternative ly , the plaintiffs proposed another, more exact ing
formula in which t he jury ’s assign ed baseline per

- hour value would be multiplied by each property’s “direct hit” hours and prorated based on each property’s pollutant concentration. Pollution concentration, plaintiffs argue d , could be calculated as follows : The formula takes the average concentrations of each of [VOCs, PM10s, and sulfur di o xide] present on each parcel and then sums them up to arrive at a property

- specif i c concentration total and to determine how that compares to the total concentrations of the hardest hit property. And we refer to the hardest hit property as the baseline for all others. The formula divides the concentration total for each property into the

. . . baseline total.
Plaintiffs acknowledged that because the model measures only the amount of time a property is hit by emissions, lower concentration totals may measure emissions that residents would not notice . It would be left
for the court an d jury to identify what total concentration level , if any,
constituted a nuisance. T he plaintiffs admitted this formula does not8

account for time class members spent asleep or away from their property, but asserted the formula was permitted under our case law
allow ing approximation of damages.
To the extent issues remain ed concerning individual damages, the plaintiffs contend ed these issues could be litigated during a “claims administration process typical to class actions.” During this process,
individu al factors such as tenure of the residents and proximity to other sources of pollution could be a ddressed

. B. GPC’s Resistance to Certification. GPC argued the residents’ claims were inherently individual, and as such, individual issues predominated ov er those common to the class

. GPC pointed to variances in testimony submitted by the residents. For example, their descriptions
of GPC’s emissions differ ed , such as “yellow dust,” “syrupy, sticky residue,” “similar to pencil shavings,” “sticky, brownish tan particulates,” “small black pellets like peppercorns,” or “dust that looks like fur.” Some
residents had moved into the neighborhood with knowledge of the emissions, while others were unaware before moving

. The neighbors had
lived in the area for varying periods, some moving to the area after the
lawsuit was filed and others living there for over fifty years. Some stated they may have received reduced pricing on their homes because of the pollution. Some lived close r to other emission sources, su ch as a

waste water treatment plant or railroad

. GPC identified seven residents (out of over 100 declarants) who stated they never had been prevented from doing anything outdoors because of the smells or emissions

. Even these residents, however, acknowled ged the prevalent odor in their neighborhood from GPC’s facility

. The individual issues, GPC argued, necessitated a property

- by

- property, person

- by

- person analysis to
determine whether GPC’s conduct created a nuisance.9

GPC also resisted the residents’ pha sed trial strategy. Specifically,
GPC objected to the use of lay testimony to infer classwide harm. GPC noted a class action must “rise or fall” with the named plaintif fs. Allowing the jury to infer, from representative testimony, conditions on
surround ing properties, GPC argued, would impermissibly alleviate each
resident ’ s burden to prove nuisance on his or her property. Moreover, using inferences would mask individual issues , hinder ing individual
defenses and thereby depriv ing GPC of due process.
GPC submitted expert testimony criticizing Dr. Rosenfeld’s model and corresponding allocation of damages. It alleged the model was
flawed because it combined disparate substances (VOS, PM10, and sulfur dioxide) to reach a n aggregate total, even though properties with differing concentrations of these substances would experience differing
harms. The model showed concentration totals on a linear scale, although testimony established that emissions would not be experienced linearly . A property with a concentration total of 2 00 would not suffer
double the lost use of enjoyment as one with 1 00. The model only accounted for wind direction and failed to account for hours during
which the residents were sleeping, on vacation , or otherwise a way from
home

. Because the model measured emissions hitting the property even
at levels that w ould not be perceptible , let alone cause compensable harm, GPC argued the mo del did not establish a nuisance. GPC also
noted the residents’ model and formula co uld not measure any alleged trespass or negligence by GPC.
C. The District Court’s Decision. T he district court granted
class certification . Noting its authority to modify or decertify the class at any time, the district court divided the class into two subclasses, one for members in close proximity to GPC, and the other for those in peripheral10 proximity. The court reasoned that plaintiffs’ air dispersion analysis

“ yields results one would expect

— properties in close proximity have comparable ‘Concentrat ion Totals’ and direct

- hit hours.” Therefore,
“n amed plaintiffs suffer the most comparable harm to absent class members who live in close proximity, and the closer the proximity the more analogous the harm.” T he court sorted six named plaintiffs into
the close

- proximity subclass and two in to peripheral proximity.
The district court further determined that common issues of law
and fact existed and that common issues predominated over individual

ones
. C ommon issues includ ed GPC’s course of conduct, its kno wledge
of the pollution, and its level and duration of emissions. Addressing GPC’s concerns, the district court , citing Miller v. Rohling , 720 N.W.2d 562 (Iowa 2006), stated,
Because Iowa measures the existence of nuisance

- level harm objectively, a nuisan ce claim brought under Iowa law is not inherently individual. Indeed, Iowa’s objective standard re n ders many of Defendant’s Due Process arguments

— idiosyncratic sensitivities, physical infirmities, life style choices, preferences for use and enjoyment, hou sekeeping habits

— immaterial to proving nuisance. Further, Iowa’s objective

- nuisance standard supports Plaintiffs’ plan for presenting the jury with lay testimony from witnesses

— whom the jury can find are “normal persons living in the community”

— to prove t he class

- wide impact of the alleged nuisance throughout each subclass area.
Miller also supports Plaintiffs’ proposed use of formulaic damages. Miller upheld the trial court’s formulaic use of an identical per hour dollar value for all of the plaintiffs notwithstanding differences in their proximity to the sources of the pollution. Miller also approved the trial court multiplying an identical per hour dollar value by sixteen hours a day

— because it assumed that “most normal people would be out of their ho me a period of eight hours a day.”

. . . Miller approving formulaic damages based on reasonable inferences and approximation renders more of Defendant’s Due Process arguments

— each class member living in a different proximity to the source of the pollution, the varying rate of emission over time, the varying velocity and direction of the wind, and the number of hours each11 plaintiff was actually or wakefully present at his or her property

— immaterial to proving nuisance.

T he district court concluded, “Due to the remedial nature of our class action rules, the manageability concerns raised by Defendant’s arguments are presently insufficient to deny certification.” GPC appealed as of right

. See Iowa R. Civ. P. 1.264(3) (“An order certifying or refusing to cert ify an action as a class action is appealable.”)

. GPC argues the district court abused its dis cretion in certifying the class and that certification infringed upon its due process rights. We retained the appeal.
II. Standard of Review. “Our review of the district court’s ruling granting or denying certification of a class is limited because the district court enjoys broad
discretion in the certification of class action lawsuits.” Legg v. W. Bank , 873 N.W.2d 756, 758 (Iowa 2016) (quoting Vos v. Farm Bureau Life Ins.
Co. , 667 N.W.2d 36, 44 (Iowa 2003)). We review a district court’s class
certification ruling for abuse of discretion. Id. The district court abuses its discretion when its “grounds for certifying a class action are clearly
unreasonable.” Id. If the district court “ ‘weigh[ed] and consider[ed] the factors and [came] to a reasoned conclusion as to whether a class action should be permitted for a fair adjudication of the controversy,’ we will
affirm.” Anderson Contracting, I nc. v. DSM Copolymers, Inc. , 776 N.W .2d 846, 848 (Iowa 2009) (alterations in original) (quoting Luttenegger v. Conseco Fin. Servicing Corp. , 671 N.W.2d 425, 437 (Iowa 2003)). To the extent GPC argues certification infringes upon its due process right to

p res ent a defense, our review is de novo. Kragnes v. City of Des Moines , 810 N.W.2d 492, 498 (Iowa 2012).12

III. Analysis.
W e must decide whether the district court abused its discretion by certifying th is class action . GPC contends that commonality, a question of law or fact common to the class, is not present as required under Iowa
R ule of Civ il P rocedure 1.261(2). GPC relatedly argues common issues of
law or fact d o not predominate over individual issues, a factor it
contends the district court failed to sufficiently weigh when conc luding a class action should be permitted for the fair and efficient adjudication of the controversy. See Iowa R. Civ. P. 1.263(1)( e ). We determine that
common issues of law or fact exis t and predominate over individual
issues

. Finally, GPC argues the certification order violates due process by interfering with its right to litigate individual defenses. We disagree
and conclude GPC will be able to litigate individual issues. We hold th e district court did not abuse its broad discretion in certifying this class
action

. A. Whether the District Court Abused Its Discretion b y Certifying the Class A ction
. Iowa Rule s of Civil Procedure 1.261 through 1.263 govern class actions. Under rule 1.262 , the district court may certify a class action if it finds all of the following:

a
. The requirements of rule 1.261 have been satisfied. b

. A class action should be permitted for the fair and efficient adjudication of the controversy.

c
. The representative parties fairly and adequately will protect the interests of the class.

Id. r. 1.262(2). Rule 1.261 provides parties may sue as a class w hen “[t]he class is so numerous .

. . that joinder of all members .

. . is impracticable” and “ [t]here is a question of law or fact common to the
class.” Id. r . 1.261 (1)

– (2). “A failure of proof on any one of the prerequisites is fatal to class certification.” City of Dubuque v. Iowa13

Trust , 519 N.W.2d 786, 791 (Iowa 1994). But at the class certification stage, “the proponent’s burden is light

. ” Id. The class action rules should be “liberally construed and the policy should favor maintenance
of class actions.” Lucas v. Pioneer, Inc. , 256 N.W.2d 167, 175 (Iowa 1977). The goal of the rules is the
efficient resolution of the claims or liabilities of many individuals in a single action, the elimination of repetitious litigation and possibly inconsistent adjudications involving common questions, related events, or requests for similar relief, and the establishment of an effective procedure for those whose economic position is such that it is unrealistic to expect them to seek to vindicate their rights in separate lawsuits. Comes v. Microsoft Corp. , 696 N.W.2d 318, 320 (Iowa 2005) (quoting 7A Charles Alan Wright, Arthur R. Miller & Mary Kay Kane, Federal Practice
and Procedure § 1754, at 49 (2d ed. 1986) [hereinafter Wright] ).
Rule 1.263 (1) lists thirteen factors the district court may consider in determining whether “the class action should be permitted for the fair and efficient adjudication of the controversy .” 1 Iowa R. Civ. P. 1.263(1).

1 Rule 1.263 (1) provides,
In determining whether the class action should be permitted for the fair and efficient adjudication of the controversy, as appropriately limited under rule 1.262(3), the court shall consider and give appropriate weight to the following and other relevant fac tors:

a
. Whether a join t or common interest exists among members of the class. b

. Whether the prosecution of separate actions by or against individual members of the class would create a risk of inconsistent or varying adjudications with respect to in dividual members of the class that would establish incompatible standards of conduct for a party opposing the class.

c
. Whether adjudications with respect to individual members of the class as a practical matter would be dispositive of the interests of other members not parties to the adjudication or substantially impair or impede their ability to protect their interest s
. d

. Whether a party opposing the class has acted or refused to act on grounds generally applicable to the class, thereby making final14 These factors “center on two broad considerations: ‘achieving judicial economy by encouraging class litigation while preserving, as much as possible, the rights of litigants

— both those presently in court and those
who are only potential litigants. ’ ” Vos , 667 N.W.2d at 45 (quoting Vignaroli v. Blue Cross of Iowa , 360 N.W.2d 741, 744 (Iowa 1985)). A key factor is whether “common questions of law or fact predominate over any questions affecting only individual members.”
Iowa R

. Civ

. P

. 1.263(1)( e ). “[T] he language of rule 1.263 indicates the district court has ‘considerable discretion’ in weighing the factors.” Anderson Contracting , 776 N.W.2d at 848 (q uoting Vignaroli , 360 N.W.2d at 744). The district court decides what weight, if any, to give each of the factors and may weigh one factor more heavily than another. Id.

_______________________ injunctive relief or corresponding declaratory relief appropriate with respect to the class as a whole.

e
. Whether common question s of law or fact predominate over any questions affecting only individual members. f

. Whether other means of adjudicating the claims and defenses are impracticable or inefficient.
g
. Whether a class action offers the most appropriate means of adjudic ating the claims and defenses. h

. Whether members who are not representative parties have a substantial interest in individually controlling the prosecution or defense of separate actions. i

. Whether the class action involve a claim that is or has be en the subject of a class action, a government action, or other proceeding. j

. Whether it is desirable to bring the class action in another forum. k

. Whether management of the class action poses unusual difficulties. l

. Whether any conflict of law s issues involved pose unusual difficulties.

m
. Whether the claims of individual class members are insufficient in the amounts or interests involved, in view of the complexities of the issues and the expenses of the litigation, to afford significant rel ief to the members of the class.15 “Whether or not we agree with the decision arrived at by the trial court is
not the issue. The issue is one of abuse of discretion.” Id. (quoting Martin v. Amana Refrigeration, Inc. , 435 N.W.2d 364, 369 (Iowa 1989 ) ). The district court has considerable leeway when deciding whether to certify the class. See, e.g. , Legg , 873 N.W.2d at 761

– 62 (affirming class certification and noting broad discretion); Kragnes , 810 N.W.2d at 500 (“We find no abuse of the district court’s broad discretion in certifying and refusing to decertify the class.”); Varner v. Schwan’s Sales Enters.,
Inc. , 433 N.W.2d 304, 306 (Iowa 1988) (concluding the district court did not “abuse[] its discretion in denying certification). GPC does not contest numerosity. See Legg , 873 N.W.2d at 759 (noting numbers alone are dispositive to show numerosity and impract icality is presumed if the class has over forty members). Nor does GPC contest the adequacy of the named plaintiffs to represent the class. Rather, GPC argues that the district court erred in certifying the class because the requirement of commonality wa s not met. GPC also contends individual issues predominate over common questions of law or
fact. We address each argument in turn.
1. Commonality. GPC relies on federal authority in arguing the commonality requirement is lacking here. Iowa’s “rules regarding class actions[] closely resemble Federal Rule of Civil Procedure 23.” Vos , 667
N.W.2d at 44. W e have relied on “federal authorities construing similar provisions” of the federal rule to interpret our state counterpart. Id

. T he
federal rule requires “questions of law or fact common to the class. ” Fed. R. Civ. P. 23(a)(2). 2

2 Federal Rule 23 provides in relevant part, (a) Prerequisites. One or more members of a class may sue or be sued as representative parties on behalf of all members only if:16

_______________________ (1) the class is so numerous that joinder of all members is impracticable; (2) there are questions of law or fact common to the class; (3) the claims or defenses of the representative parties are typical of the claims or defenses of the class; and (4) the representative parties will fairly and ade quately protect the interests of the class. (b) Types of Class Actions
. A class action may be maintained if Rule 23(a) is satisfied and if: (1) prosecuting separate actions by or against individual class members would create a risk of: (A) inconsistent or varying adjudications with respect to individual class members that would establish incompatible standards of conduct for the party opposing the class; or (B) adjudications with respect to individual class members that, as a practical matt er, would be dispositive of the interests of the other members not parties to the individual adjudications or would substantially impair or impede their ability to protect their interests; (2) the party opposing the class has acted or refused to act
on gr ounds that apply generally to the class, so that final injunctive relief or corresponding declaratory relief is appropriate respecting the class as a whole; or (3) the court finds that the questions of law or fact common to class members predominate over any questions affecting only individual members, and that a class action is superior to other available methods for fairly and efficiently adjudicating the controversy. The matters pertinent to these findings include: (A) the class members’ interests in individually controlling the prosecution or defense of separate actions; (B) the extent and nature of any litigation concerning the controversy already begun by or against class members; (C) the desirability or undesirability of concentrating the litigat ion of the claims in the particular forum; and (D) the likely difficulties in managing a class action. Fed. R. Civ. P. 23 (a)

– (b).17

GPC argues Wal

- Mart Stores, Inc. v. Dukes , supports its challenge

to the district court’s determination on commonality. 564 U.S. 3 38, 349,
131 S. Ct. 2541, 2551 (2011). In Dukes , the plaintiffs sought to certify a
class action of all women employed at Wal

- Mart stores nationwide since
1998 , alleging Wal

- Mart ’ s promotion policies discriminated on the basis
of sex in violation of Title VII. Id. at 346, 131 S. Ct. at 2549. T he Dukes
Court noted c ommonality “is easy to misread, since ‘[a]ny competently crafted class complaint literally raises common “questions” ’ ” Id

. at 349,
131 S. Ct. at 2551 (quoting Richard A. Nagareda, Class Certification in the Age of Aggregate Proo f

, 84 N.Y.U. L. Rev. 97, 131

– 32 (2009)). But “[ c ] ommonality requires the plaintiff to demonstrate that the class members ‘have suffered the same injury.’ ” Id. at 3 49

– 50, 131 S. Ct. at
2551 (quoting Gen. Tel. Co. of Sw. v. Falcon , 457 U.S. 1 47, 15 7 , 1 02
S. Ct. 2364, 2370 (1982)). It was not sufficient that class members “have all suffered a violation of the same provision of law.” Id. at 350, 131 S.
Ct. at 2551. Rather, “ c laims must depend on a common contention” of
“such a nature that it is capable of classwide resolution

— which means
that the determination of its truth or falsity will resolve an issue that is central to the validity of each one of the claims in one stroke.” Id. T o satisfy the commonality requirement , “ ‘[ e ] ven a single [ common ] quest ion ’ will do.” Id. at 359, 131 S. Ct. at 2556 (alteration in original) (quoting Richard A. Nagareda, The Preexistence Principle and the Structure of the Class Action , 103 Colum. L. Rev. 149, 176 n.10 (2003))

. The Dukes C ourt concluded that no common question of law or fact was present. Id. at 359, 131 S. Ct. at 2556

– 57

. Unlike an “assertion of discriminatory bias on the part of the same supervisor,” t he class
members18 held a multitude of different j o bs, at different lev els of Wal

- Mart hierarchy, for variable lengths of time, in 3, 400 stores, sprinkled across 50 states, with a kaleidoscope of supervisors (male and female), subject to a variety of regional policies that all diff ered

. . . . Id. at 350, 359

– 60, 131 S. Ct. at 2551, 2557 (alteration in original) (quoting Dukes v. Wal

- Mart Stores, Inc. , 603 F.3d 571, 652 (9th Cir. 2010) (Kozinski, C.J., dissenting) )

. The employees failed to identify a specific employment practice tying together their nationwide claims. I d. at 357, 131 S. Ct. at 2555. By contrast , the distri ct court here found several common questions of both law and fact

. The class includes only “members who live in the vicinity of Defendant’s Muscatine facility and allegedly suffered damages from Defendant’s course of conduct.” GPC engaged in a
common course of cond uct regarding all class members. Specifically, Defendant operated outdated, high

polluting dryers and coal

- boilers, with virtually n o controls to reduce emissions, [which] purportedl y released noxious smoke and odor and haze into the surrounding neighborhoods for years, which caused a class

- wide nuisance. Almost identical evidence will be required to establish the level and duration of Defendant’s emissions, the reasonableness of Def endant’s operations, and the causal connection, if any, between the injuries allegedly suffe red and Defendant’s liability. Although the “nature and amount of damag es” may differ for each class
member , the district court concluded, “The central factual ba sis for all of
Plaintiff’s claims .

. . is GPC’s course of conduct and knowledge of its potential hazards. Thus, P laintiffs’ theory presents a common nucleus of operative fact.” We agree. All class members allegedly suffered a common injury

— air pollutio n emanating from GPC that interfered with the use and enjoyment of their property.
GPC argues the named plaintiffs did not suffer the same injury as
other class members. “[A] class representative must be part of the class19

and ‘ possess the same interest and suffer the same injury ’ as class
members.” Hammer v. Branstad , 463 N.W.2d 86, 90 (Iowa 1990) (alteration in original) (quoting E. Tex. Motor Freight Sys., Inc. v. Rodriguez , 431 U.S. 395, 403, 97 S. Ct. 1891, 1896 (1977)). Initially, t he
district court was “not persuaded class representatives ha [d] suffered the same injury shared by all members of the class.” The court observed
that Sharon Mockmore, the class member located closest to GPC, experienced a “concentration total” of 317.21, while Bobbi e Lynn Weatherman, the class member located furthest from GPC, experienced a
“concentration total” of only 71.50. Thus, “the effects of Defendant’s emissions at the edge of the class boundary [could not] be inferred from the testimony of class members liv ing in close proximity to Defendant.”
But the district court resolved that disparity by creating two subclasses, entitled “close proxi mity” and “peripheral proximity , ” and group ing the named plaintiffs accordingly. Within these subclasses, the district c ourt found the named plaintiffs were “ideal representatives for absent class members who live nearby.” Our rules allow the district court to define
subclasses . Iowa R. Civ. P. 1.262(3)( c ) (“If appropriate, the court may do any of the following:

. . . Div ide a class int o subclasses and treat each
sub class as a class.”). Other courts applying equivalent class action rules have determined the commonality requirement was met when neighboring property owners sue d a polluter under nuisance or negligence theor ies.
See Ebert v. Gen . Mills, Inc. , 823 F.3d 472, 478 (8th Cir. 2016) (“Here, the district court recognized that the issues of General Mills’ standardized conduct of alleged contamination and the remedies sought by the class are common to all plaintiffs .

. . .”); Rowe v. E.I. Dupont De Nemours &
Co. , 262 F.R.D. 451, 457 (D.N.J. 2009) (commonality present for20 nuisance claim alleging ground water contamination); Collins v. Olin Corp. , 248 F.R.D . 95, 101 (D. Conn. 2008) (finding common questions
existed as to pollut e r’s course of conduct for contaminated soil and water); Mejdreck v. Lockformer Co. , No. 01 C 6107, 2002 WL 1838141, at
*3 (N.D. Ill. Aug. 12, 2002) (“Plaintiffs allege this contamination constitutes standardized conduct towards all proposed class m embers and there are therefore common questions of law and fact.”); Boggs v. Divested Atomic Corp. , 141 F.R. D. 58, 64 (S.D. Ohio 1991) ( stating plaintiffs had identified common questions of extensiveness of emissions, what caused them, what precautions wer e taken, and economic impact of emissions) ; Berdysz v. Boyas Excavating, Inc. , ___ N.E.3d ___, ___ , 2017 WL 632445, at *6 (Ohio Ct. App. Feb. 16, 2017) (finding common issues and affirming certification in air pollution case).
We reach the sa me conclusion under this record and hold the
district court did not abuse its discretion in finding the commonality requirement was satisfied within the two subclasses

. 2. Predominance

. The question of whether common or individual issues predominate has been characterized as “fairly complex.” Vignaroli , 360 N.W.2d at 744. “ Inherent in our inquiry into the predomination issue is the recognition [that] the class action device is appropria te only where class members have common complaints that can be presented by designated representatives in the unified proceeding.” Id

. Predominance “necessitates a ‘close look’ at ‘the difficulties likely to be encountered in the management of a class

ac tion.’ ” Vos , 667 N.W.2d at 46 (quoting Rothwell v. Chubb Life Ins. Co. of Am ., 191 F.R.D. 25, 28

– 29 (D.N.H. 1998) ). The predominance inquiry is “qualit ative rather than quantitative”; merely “ a common question does not end the inquiry. ” Ebert , 823 F.3d at 478 ; see also William B.21

Rubenstein , Newberg on Class Actions § 4:50 (5th ed. ), Westlaw (database updated Dec. 2016) [hereinafter Newberg ]

. Individual claims need not “be carbon copies of each other” to determine common issues predominate. Vignaroli , 360 N.W.2d at 745. The test for pr edominance “is a pragmatic one.” Luttenegger , 671 N.W.2d
at 437

. When common questions represent a significant aspect of the case and they can be resolved for all members of the class in a single adjudicatio n, there is a clear justification for handling the dispute on a representative rather than an individual basis

. . . . [C]ourts have held that a [class action] can be brought .

. . even though there is not a complete identity of facts relating to all class members, as long as a “common nucleus of operative facts” is present.

. . . The common questions need not be dispositive of the entire action. In other words, “predominate” should not be automatically equated with “determinative” or “significant.” Therefore, when one or more of the central issues in the action are common to the class and can be said to predominate, the [class] action will be considered proper.

Id. (alteration s in original) (quoting Wright § 1778, at 528

– 33 ). “A claim
will meet th e predominance requirement when there exists generalized evidence which proves or disproves an element on a simultaneous, class

wide basis, since such proof obviates the need to examine each class member’s individual position.” Vos , 667 N.W.2d at 45 (quot ing Cope v. Metro. Life Ins. Co. , 696 N.E.2d 1001, 1004 (Ohio 1998) )

. The dist rict court issued a forty

- seven

- page ruling, with eleven pages addressing predominance. See Anderson Contracting , 776 N.W.2d at 849 (noting the thoroughness of the district c ourt’s ruling). Ultimately, the district court determined, While variations in the individual damage claims are likely to occur and other sources of emissions may pose unusual difficulties, common questions of law or fact regarding Defendant’s liability predominate over questions affecting only individual class members such that the subclasses22 should be permitted for the fair and efficient adjudication of this controversy.

The district court also addressed the other factors considered under r ule 1.263(1). One of the purposes of class action procedures “is to provide small claimants an economically viable vehicle for redress in court.” [ Martin ], 435 N.W.2d at 366.

. . . Given the complexities of the liability issue and the expenses of this lit igation, the claims of individual class members are insufficient in the amounts or interests involved to afford significant relief to the proposed subclass members without certification of the subclasses. Finally, class action will establish Defendant’s l iability in a single proceeding for thousands of Muscatine residents. This will avoid unacceptable costs and repetition for both parties.

In Comes , we emphasized the district court’s broad discretion to weigh the thirteen factors in deciding class certi fication

. In most cases some of the thirteen factors [regarding the fair

and

- efficient

- administration

- of

- justice test] will weigh against certification and some will weigh in favor. It is for the trial court, employing its broad discretion, to weigh the competing factors and determine whether a class action will provide a fair and efficient adjudication of the controversy. Thus, even if [defendant] is correct in its assertion four of the factors weigh against certification, that does not preclude the co urt from certifying the class action if, in its opinion, those factors are outweighed by other fa ctors supporting certification.

Comes , 696 N.W.2d at 322 (quoting Howe v. Microsoft Corp. , 656 N.W.2d 285, 289 (N.D. 2003) )

. “Further, a safety net is provided for cases in which certification is improvidently granted: the court may decertify the class at a later time.”
Id. at 324; s ee also Vos , 667 N.W.2d at 54

– 55 (affirming district court’s
decision to decertify class because individual issues predominated). Or
t he district court may bifurcate the trial into separate phases for liability and damages. See Hammer , 463 N.W.2d at 88; see also Newberg § 10:623 (“[A] common use of bifurcation .

. . is to try liability issues to a jury before damages

. . . .”). When
de fendant’s activities present a “common course of conduct” so that the issue of statutory liability is common to the class, the fact that damages .

. . may vary for each party does not require that the class action be terminated. Legg , 873 N.W.2d at 759

– 60 (alterations in original) (quoting Luttenegger , 671 N.W.2d at 437).
“Certification of a class act ion does not depend on a determination
of whether the plaintiffs will ultimately prevail on the merits.” Vos , 667 N.W.2d at 45. However, determining whether the requirements for class
certification are met “will entail some overlap with the merits of the plaintiff’s underlying claim. That cannot be helped.” Dukes , 564 U.S. at
351 , 131 S. Ct. at 2551 . Nonetheless, we decline to “engage in free

ranging merits inquiries at the certification stage.” Amgen Inc. v. Conn

. Ret. Plans & Trust Funds , 568 U.S. ___, 133 S. Ct. 1184, 1194

– 95 (2013).
The m erits should be analyzed only to the extent relevant in determining
whether the rules have been satisfied. Id. at ___, 133 S. Ct. at 1196. We begin, as the district court did, with the plaintiffs’ first ca use of
action , nuisance. See Newton v. Merrill Lynch, Pierce, Fenner & Smith,
Inc. , 259 F.3d 154, 172 (3d Cir. 2001) (“To determine whether the claims alleged by the putative class meet the requirements for class certification,
we must first examine the unde rlying cause of action

. . . .”). The
l egislature has defined nuisance as “[w] hatever is injurious to health, indecent, or unreasonably offensive to the senses, or an obstruction to the free use of property, so as essentially to interfere unreasonably wit h the comfortable enjoyment of life or property .” Iowa Code § 657.1 (1) (2015)

. Under s ection 657.2 (1) , “occasioning noxious exhalations, unreasonably offens ive smells, or other annoyances , [ which] becomes24 injurious and dangerous to the health, comfort, or property of indivi duals or the public” constitute a nuisance. Id. § 657.2(1).
The nuisance statute does not supersede common law nuisance.
See Freeman , 848 N.W.2d at 67. Rather, s tatutory nuisance claims are “supplemented by common law principles g overning private nuisances.” Perkins v. Madison Cty. Livestock & Fair Ass’n , 613 N.W. 2d 264, 271 (Iowa 2000). We have defined a common law nuisance as “an actionable interference with a person’s interest in the private us e and enjoyment of the person’s l and.” Id. (quoting Weinhold v. Wolff , 555 N.W.2d 454, 45 9 (Iowa 1996) )

. Whether a lawful business is a nuisance depends on the reasonableness of conducting the business in the manner, at the place, and under the circumstances in question. Thus the exis tence of a nuisance does not depend on the intention of the party who created it. Rather, it depends on the following three factors: priority of location, the nature of the neighborhood, and the wrong complained of.

Id. (quoting Weinhold , 555 N.W.2d at 459). Alleged nuisances are
assessed under an “ objective, normal

- person” standard. Id. “Thus, if ‘normal persons living in the community would regard the invasion in question as definitely offensive, seriously annoying or intolerable’ then the invasion is significant enough to constitute a nuisance.” Id. (quoting
Weinhold , 555 N.W.2d at 459 )

. Whether a nuisance exists is a factual inquiry. Patz v. Farmegg
Prod s ., Inc. , 196 N.W.2d 557, 561 (Iowa 1972). To recover against GPC, the plaint i ffs must establish common facts as to “ priority of location, the
nature of the neighborhood [ involving co mmon proof assessing the locale] , and the wrong complained of. ” Perkins , 613 N.W.2d at 271.
A t oral argument and in their appellate brief the plaintiffs conceded priority of location favored GPC as to all class members. GPC’s25 operations commenced in 1943 , and in the words of plaintiffs’ counsel, a resident would have had to be “living under a rock” not to know of GPC’s activities in the neighborhood. The plaintiffs have also eliminated many
ind ividual issues by confining their claims to property damages without claiming diminution in value or alleging personal injury claims. Any class member may opt out. 3 See Iowa R. Civ. P. 1.267 (1) (allowing putative class member to “elect to be excluded” un less he or she is a class representative, there has bee n an affirmative finding under r ule 1.263( a ), ( b ), or ( c ), or a counterclaim has been asserted against the member). Because the “normal person” standard is an objective one, any idiosyncratic sensiti vity, physical infirmities, life style choices, preferences for use and enjoyment, or housekeeping habits are immaterial to proving
whether defendant’s conduct created a nuisance

. See, e.g. , Miller , 720 N.W.2d at 569 (awarding damages despite witness testi mony emissions were “not that bothersome”). Objective standards more readil y present common questions than subjective standards

. See Amgen , 568 U.S. at

___ , 133 S. Ct. at 1191. In Amgen , the United States Supreme Court evaluated whether the objective element of “materiality” was a common or individual question when deciding whether to certify a class a ction alleging securities fraud.

3 Indeed, at least seventeen individual class

- member plaintiffs have filed expedited civil actions. See Pl.’s App l. for Interlocutory Appeal, Wittenberg v. Grain Processing Corp. , No. 17

– 0058 (filed Jan. 12, 2017) (six individuals); Pl.’s Appl

. for Interlocutory Appeal, Tate v. Grain Processing Corp. , No. 17

– 0062 (filed Jan. 12, 2017) (eleven individuals). These expedited civil actions allege property and medical damages, while the Freeman class members have limited damages to lost use and enjoyment. The individual plaintiffs stated they chose the e xpedited civil action forum because of the opportunity to have cases resolved more expeditiously than a class claim. See Iowa R. Civ. P. 1.281 (4) ( b ) (“Unless that court otherwise orders for good cause shown, expedited civil actions must be tried within on e year of filing.”).26 Because materiality is judged according to an objective standard, the materiality of Amgen’s alleged misrepresentation s and omissions is a question comm on to all members of the class.

. . . The alleged misrepresentations and omissions, whether material or immaterial, would be so equally for all investors composing the class. As vital, the plaintiff class’s inability to prove materiality would not result in individual questions predominating. Instead, a failure of proof on the issue of materiality would end the case, given that materiality is an essential element of the class members’ securities

- fraud claims. As to mate riality, therefore, the class is entirely cohesive: It will prevail or fail in unison.
Id. Similarly, i f the residents fail to demonstrate that a normal person in the locality would find the conditions existing throughout the subclass

area “definitely o ffensive, seriously annoy ing or intolerable,” then the residents will fail to meet their burden, and the claim will fail. Weinhold , 555 N.W.2d at 459 (quoting Restatement (Second) of Torts § 821F cmt. d , at 106 (1979 ))

. Given the plaintiffs’ showing that the three factors

— priority of location, the nature of the neighborhood, and the wrong complained of

—

are objective, common factors , it appears the factual determination of whether a nuisance exists is capable of being made on a classwide basis.
GPC a rgues Perkins is fatal to class certification because it applied a property

- by

- property determination to resolve nuisance claims , showing that individual issues will predominate over common questions

. 613 N.W.2d at 27 3 (“We examine each plaintiff’s claim independently of the other plaintiffs’ claims so that a plaintiff’s claim will succeed or fail on the basis of that plaintiff’s particular circumstances.”). We disagree
that Perkins requires reversal. In Perkins, neighboring property owners brought a nui sance action in equity against operators of a figure

- eight auto racetrack built on the county fairgrounds. Id. at 268 . The plaintiffs
all lived in their homes nearby before the race track was built and thus had priority of location. Id. at 271

– 72. Races occurred seven nights a27

year. Id. at 272. The d istrict court denied recovery, finding “ ‘the seven
time invasion’ did not rise to the level of a nuisance.” Id. at 272

– 73. We applied de novo review and affirmed as to three of the prop erty owners located between 975 and 1150 feet from the track. Id. at 273

– 74 . But we reversed as to one plaintiff who lived adjacent to the fairgrounds and whose yard was seventy

- seven feet from the racetrack. Id. at 274. She testified the pit area, loc ated on her property line, was “extremely noisy”
and that “ [ l ] ights, noise, dust, smoke and exhaust fumes emanate from the track and pit area directly onto [her] property, including the house.”
Id

. We found she proved her nuisance claim while the other p roperty

owners ( who lived the length of three to four football fields away ) did not.
Id.
Perkins is distinguishable. It was not a class action. We reviewed
the evidence de novo to decide the merits of the nuisance claims. Id . at 267. By contrast , we are reviewing here the district court’s procedural ruling on class certification for abuse of discretion. The merits of the nuisance claims will be decided at trial. The district court appropriately divided the case into two subclasses, based on the dis tance from the source of the alleged nuisance. Moreover, Perkins did not involve negligence claims in which the reasonableness of the defendant’s conduct is an issue common to all the neighboring property

- owner plaintiffs. Negligence and nuisance are distinct theories. Dalarna Farms v. Access Energy Coop. , 792 N.W.2d 656, 659 (Iowa 2010). We explained
the distinction between the two in Bormann v. Board of Supervisors , stating, Negligence is a type of liability

- forming con duct, for example, a failure to act reasonably to prevent harm. In contrast, nuisance is a liability

- producing condition. Negligence may28 or may not accompany a nuisance; negligence, however, is not an essential element of nuisance. If the condition cons tituting the nuisance exists, the person responsible for it is liable for resulting damages to others even though the person acted reasonably to prevent or minimize the deleterious effect of the nuisance. 584 N.W.2d 309, 315 (Iowa 1998) (citations omitte d) . In other words, nuisance is a condition, not an act or failure to act by the party responsible. See id. [ T ]he true distinction between negligence and nuisance is that “ to constitute a nuisance ‘ there must a degree of danger (likely to result in dam age) inherent in the thing itself, beyond that arising from a mere failure to exercise ordinary care.’ ”

Dalarna Farms , 792 N.W.2d at 659 (quoting Martins v. Interstate Power
Co. , 652 N.W.2d 657, 661 (Iowa 2002)).
Under both nuisance and negligence theories, the harm caused by
the defendant’s conduct is relevant. In Martins , t he plaintiffs claimed
electrical transmission lines emitted stray voltage , harming dairy cows on an adjoining farm and reducing milk production

. 652 N.W.2d at 6 59.
S tray voltage was an “ inherent part of supplying electricity,” but problems in electrical systems could increase its frequency. Id. at 662 (quoting
Peter G. Yelkovac, Homogenizing the La w of Stray Voltage: An Electrif ying Attempt to Corral the Controversy , 28 V al. U. L. Rev. 1111, 1112

– 13 (1994)). To constitute a nuisance, we pointed out the “degree of danger likely to result in damages must be inherent in the thing itself.” Id. at 664. We concluded “[e]xcessive stray voltage from an electric utility
resultin g in damage to a dairy herd [met] that test.” Id. Assessing whether GPC’s conduct created an inherent risk of danger will be a common legal question affecting both the plaintiffs’ nuisance (the resulting condition) and negligence (the reasonableness of t he conduct)
claims.29 In addition, the plaintiffs’ negligence claim s will require evidence of GPC’s course of conduct, its duty of care and corresponding breach , and its knowledge of the harms caused. Raas v. State , 729 N.W.2d 444, 447 (Iowa 2007) (noting to establish claim of negligence plaintiffs must show “a duty of care,” a breach of duty, that the breach “was a proximate cause of their injuries,” and damages). The plaintiffs ’ plan to offer evidence GPC could have upgraded its coal

- burning equipment w ith cleaner burning , natural gas

- fired equipment earlier , and had it done so, much of the air pollution would have been avoided. Whether GPC acted unreasonably by delaying that equipment upgrade appears to be a
common issue. Proving trespass will involve similar common evidence , such as
whether harms can be attributed to GPC and whether emission s interfered with the residents’ exclusive land possession. See Free man , 848 N.W.2d at 67 ( addressing cases deciding whether air poll ution
constituted a trespass). GPC’s arguments against certifying these claims go to the merits. 4 Class action treatment appears to be the most efficient way to
resolve these issues. See Iowa R. Civ. P. 1.263(1)( g ) (instructing court to
consider whethe r class action “offers the most appropriate means of adjudicating the claims and defenses”). Moreover, the complexity of these questions may hinder the ability of some class members to get relief due to the expense of expert testimony. Id. r. 1.263(1)( m ) (directing consideration of “[w]hether the claims of the individual class members
are insufficient in the amounts or interests involve d , in view of the

4 For example, GPC asserts that no physical invasion is shown by Dr. Rosenfeld’s model, that GPC did not cause the physical invasion because testing of residue revealed it was from an other source, and that even non negligently run mill s produce emissions.30 complexities of the issues and the expenses of litigation, to afford significant relief to the members of the class”). The district court acted within its discretion in concluding that individual differences among
class members were not fatal to class certification. GPC contends individual issues of causation and injury predominate over common questions. We disagree. Contesting causation, GPC notes some class members live closer to other industrial

sources of pollution , specifically the active railroad tracks or the sewage treatment plant

. But the industrial character of the surrounding neighborhood do es not preclude a finding of nuisance. See Gacke v. Pork Xtra, L.L.C. , 684 N.W.2d 168, 180 (Iowa 2004) ( affirming finding of
nuisance from hog confinement facility , even though it was a “customary enterprise in the neighborhood”); Bates v. Quality Ready

- M ix Co. , 261 Iowa 696, 704, 154 N.W.2d 852, 858 (1967) (affirming nuisance finding even though in commercial area). We also observe there was testimony indicating residents could distinguish between odors attributed to GPC
and the sewage plant. See Olden v . LaFarge Corp. , 383 F.3d 495 , 508 (6th Cir. 2004) (affirming certification when plaintiffs could show injury from contaminants directly attributable to defendant, despite other industrial sources in area). We also do not see an issue in the plaintiffs’ use of representative testimony to show classwide harm. In Tyson Foods, Inc. v. Bouaphakeo , the Supreme Court addressed whether representative evidence could be used in proving harm to employees

. 577 U.S. ___, ___, 136 S. Ct. 1036,
1046 (2016)

. Employees alleged a violation of the Fair Labor Standards
Act (FLSA) when an employer refused to compensate them for time donning and doffing protective clo thing. Id. at ___, 136 S. Ct. at 1042. Because there were no records of time actually spent donni ng and doffing31 and time varied among employees, plaintiffs relied on a representative sample to allow an expert to compute the average time spent. Id. at ___,
136 S. Ct. at 1043 . The employer moved to set aside the jury verdict, arguing that the variatio n in donning and doffing time required individual inquiries preventing certification. Id. at ___, 136 S. Ct. at
1044 . Under the FLSA, an employee bringing an individual claim was permitted to establish hours worked by producing sufficient evidence to

perm it a “just and reasonable inference.” Id. at ___, 136 S. Ct. at 1047 (quoting Anderson v. Mt

. Clemens Pottery Co. , 328 U .S. 680, 687, 66
S. Ct. 1187, 1192 (1946), superseded by statute as recognized in Integrity Staffing Sol s ., Inc. v. Busk , 574 U.S. _ __, 135 S. Ct. 513 (2014)) . As such, the Court concluded class action plaintiffs could use a representative sample to provide a reasonable inference of classwide harm. Id. Similarly, the typical method of proving the objective “normal person in the commun ity” standard for nuisance is to present representative, lay testimony from members of the community that they were disturbed by the condition. See Gacke , 684 N.W.2d at 180 (“The testimony of the plaintiffs and of the witnesses they presented convinced the court that normal persons would be and were substantially annoyed

. . . .”); Weinhold , 555 N.W.2d at 460 (stating that lay witnesses presented from surrounding farms established offensiveness to persons of “ordinary sensibilities”); Bates , 2 61 Iowa at 702, 154 N.W.2d at 857 (“Other witnesses living in the vicinity testified to the noises and being disturbed by operation of the plant.”). This is the method of proof proposed by the plaintiffs. Moreover, we have previously approved the use o f a formula employing reasonable inferences to calculate nuisance damages. Miller , 720 N.W.2d at 569. In Miller , neighbor s claimed the defendants’ grain

-32 harvesting activities constituted a nuisance. Id. at 56 6 . Testimony
confirmed that the defendants’ “emissions during harvest season were so pervasive that they blanketed not only the plaintiffs’ vehicles and personal property located outside their residences, but also filtered into the interior of the plaintiffs’ homes.” Id. at 569. Awarding damages f or loss of enjoyment during harvest season , the district court used a

per diem formula, compensating the plaintiffs at the rate of “$6 per hour for 16 hours a day for 90 days a year.” Id. at 570. The defendants argued this calculation was in error, as “e ach plaintiff lived in different proximity to the defendants’ property and was impacted differently by the defendants’ grain storage activities.” Id. at 571. In addition, the

per diem formula did not account for hours each individual plaintiff may
not ha ve been present at the property. Id. We upheld the per diem
calculation. Id. We noted, If the record is uncertain and speculative whether a party has sustained damages, the fact finder must deny recovery. But if the uncertainty is only in the amount of damages, a fact finder may allow recovery provided there is a reasonable basis in the evidence from which the fact finder can infer or approximate the damages

. Id. at 572 (emphasis added) (quoting Sun Valley Iowa Lake Ass’n v.
Anderson , 551 N.W.2d 621 , 641 (Iowa 1996)). On this basis, we affirmed the district court’s calculation, but reduced the damages of two plaintiffs: one because she did not primarily reside on the property and the other because she had negotiated for a lesser rent price because o f the
nuisance. Id. at 571

– 72. So long as the residents establish the emissions constituted a nuisance on each property (fact of harm), reasonable inferences may be used to approximate damages. See id. GPC argues that class certification will deny it t he fair opportunity to contest whether individual homeowners have suffered injury or33 damage. We disagree . The plaintiffs have proposed a formula for damages. GPC can contest the appropriateness of that formula before the jury. If a special jury verdict is entered approving this formula and that verdict is supported by substantial evidence, then potentially this formula can be used in subsequent claims administration by the court while preserving GPC’s due process and jury trial rights. If no damage
for mula is approved, then there would have to be subsequent individual trials on damages. Either way, GPC’s rights would be protected

. A possibility that the class includes some uninjured residents will

not bar certification at this time . Requiring plaintiffs to show every member of the class was exposed to contaminants at a high enough level
to be co nsidered a nuisance would “ask[ ] the court to make a class

certification ruling based on the merits of the case, something we have uniformly rejected.” Comes , 69 6 N.W.2d at 325 (declining to require plaintiffs prove “ each class member actually paid some portion of a passed

- on overcharge ” in an antitrust claim). Evidence plaintiffs suffered
contamination at sufficient levels to recover for nuisance “goes to proof of damages, rather than to common liability issues.” Luttenegger , 671 N.W.2d at 440 (holding that court did not have to make case

- by

- case determination of whether fee charged was improper at certification stage). “[T]he fact that a potential cl ass action involves individual damage claims does not preclude certification when liability issues are
common to the class.” Id. (quoting Iowa Trust , 519 N.W.2d at 792 ). GPC’s objections at this stage to Dr. Rosenfeld’s model are likewise unavailing. Assertions that “methods are flawed and incapable of calculating injury and damages to the class as a whole constitute [] a challenge going directly to the merits of the case and should not be resolved at this pre liminary stage.” Anderson Contracting , 776 N.W.2d at34

855

. At the certification stage, “[c]alculations need not be exact”; they must simply “be consistent” with liability, making just and reasonable inferences that are not speculative. Comcast Corp. v. B ehrend , 569 U.S.

_

__, ___, 133 S. Ct. 1426, 1433 (2013). Moreover, GPC’s defense that
D r. Rosenfeld’s study is “unrepresentative or inaccurate” is “itself common to the claims made by all class members.” Bouaphakeo , 577 U.S. at ___, 136 S. Ct. at 1047. Class certification is supported by many cases applying equivalent
rules. In Sterling v. Velsicol Chemical Corporation , the United States Court of Appeals for the Sixth Circuit addressed the propriety of a class
action in a mass tort case alleging stric t liability, common law negligence, trespass, and nuisance theories . 855 F.2d 1188, 1194 (6th Cir. 1988).
The d efendant allegedly deposited ultrahazardous material into a landfill, polluting ground water used by neighboring residents. Id. at 1193. In affirming class certification, the Sixth Circuit stated, In complex, mass, toxic tort accidents, where no one set of operative facts establishes liability, no single proximate cause equally applies to each potential class member and each defendant, and individual issues outnumber common issues, the district court should properly question the appropriateness of a class action for resolving the controversy. However, where the defendan t’s liability can be determined on a class

- wide basis because the cause of the disaster is a single course of conduct which is identical for each of the plaintiffs, a class action may be the best suited vehicle to resolve such a controversy. In the inst ant case, each class member lived in the vicinity of the landfill and allegedly suffered damages as a result of ingesting or otherwise using the contaminated water. Almost identical evidence would be required to establish the level and duration of chemica l contamination, the causal connection, if any, between the plaintiffs’ consumption of the contaminated water and type of injuries allegedly suffered, and the defendant’s liability.
Id. at 1197

.35

Other federal courts have affirmed class certification i n tort actions brought by neighboring property owners over pollution to avoid the “duplicative litigation” of individual lawsuits

. Gintis v. Bouchard Transp.
Co. , 596 F.3d 64 , 67 (1st Cir. 2010) ; see Olden , 383 F.3d at 508 (affirming certification based in part on “common argument that the class’s properties are regularly covered in cement dust, causing minor property damage” ); Mejdrech v. Met

- Coil Sys. Corp. , 319 F.3d 910, 911 (7th Cir. 2003) (affirming certification becau se “[t]he questions whether
Met

- Coil leaked TCE in violation of law and whether the TCE reached the soil and groundwater beneath the homes of the class members are common to all the class members”); Navelski v. Int’l Paper Co. , ___ F. Supp. 3d ___, ___, 2017 WL 1132569, at *18 (N.D. Fla. Mar. 25, 2017) (affirming certification of nuisance and negligence claims from dam collapsing “[b]ecause in this case, every aspect of liability can be resolved on a classwide basis, it would be neither efficient nor fair to anyone, including Defendant, t o hold over 300 trials to hear the same evidence and decide the same liability issues”); Mejdreck , 2002 WL 1838141, at *7 (stating “it would be wholly inefficient to try thousands of separate cases that would allege the same misconduct and provide the same proof of such” in negligence and nuisance pollution claims); LeClercq v. Lockformer Co. , No. 00 C 7164, 2001 WL 199840, at *7 (N. D. Ill. Feb. 28, 2001) (noting proof “ would be identical” as to “history of operations, the spillage, the impact on the land, soil, and water, [and] possible remedies”
and “ [ r ] epetitive discovery for individual cases on the same core issues would be wasteful”); Cook v. Rockwell Int’l Corp. , 181 F.R.D. 473, 480 (D. Colo. 1998) ( “Signifi cant elements of Plaintiffs’ ca s e in chief

. . . will be presented through the testimony of five experts. This testimony will apply to the class es as a whole.” ); Boggs , 141 F.R. D. at 67 ( “If these36 claims were tried separately, the amount of repetition would be manifestly unjustified. To the extent that each claim of each plaintiff depends upon proof concerning the history of operations at the plant, the nature, timing , extent and cause of emissions, .

. . that proof would be virtually identical in each case.” ); Bates v. Tenco Servs., Inc. , 132 F.R.D. 160, 1 64 (D.S.C. 1990) ( “The common questions in this suit will be the cause of the ground water contamination, the defendants’ liability, and the alleged effects of jet fuel contamination on the neighborhood and the people who have lived there.” ); Wehner v. Syntex Corp. , 117 F.R.D. 641, 645 (N.D. Cal. 1987) ( “Significant judicial economies are served by trying the common issues [of contamination].” ); cf. Jackson v. Unocal Corp. , 262
P.3d 874 , 890 (Colo. 2011) (en banc) ( concluding , in a state court case, common issues of asbestos contamination predominated despite individual damages issues ); 7

- Eleve n Inc. v. Bowens , 857 N.E.2d 382 , 395 (Ind. Ct. App. 2006) ( “Although these concerns [of individual issues] may be legitimate, we cannot conclude that the y outweigh the economies of time, effort, and expense that will be achieved by allowing the class action to proceed on the issues defined by the trial court.” ); Claborne v.
Hous . Auth. of New Orleans , 165 So. 3d 268 , 284 (La. Ct. App. 2015) ( “We
also recognize that the risk in trying some 2900 individual cases could
result in non

- uniformity and inconsistent adjudications on the common
issues.” ) ; Doyle v. Fluor Corp. , 199 S.W.3d 784 , 789

– 90 (Mo. Ct. App. 2006) ( “Although individual questions of damages or individual defenses may remain after the common issues here are resolved, the need for individualized proof .

. . does not defeat the predominance of the common
issues.” ); Freeman v. Blue Ridge Paper Prods., Inc. , 229 S.W.3d 694 , 706 (Tenn. Ct. App. 200 7) ( concluding class action is superior becau se of single course of conduct)

.37

Still other courts have decline d to certify a class action for
nuisance claim s because of the individualized nature of determining contamination on each property. See Gates v. Rohm & Haas Co. , 655 F.3d 255, 272 (3d Cir. 2011) (“[G]iven the potential difference in contamination on the properties, common issues do not predominate.”);
Powell v. Tosh , No. 5:09

- CV

- 00121, 2013 WL 4418531, at * 8 (W.D. Ky. Aug. 2, 2013) (“[E]ach Plaint iff’s experience as to the intensity and duration (or lack thereof) of the hog odor is susceptible to marked
variation. Fu rther, each named Plaintiff’s .

. . property is situated uniquely with respect to the barns in question.”); Fisher v. Ciba Specialty
Chem s . Corp. , 238 F.R.D. 273, 307 (S.D. Ala

. 2006) (“[B]oth the existence
of contamination and the risk of future contamination will have to be proven on a property

- by

- property basis.”); see also Ga

. - Pac. Corp. v.
Carter , 265 S.W.3d 107, 114 (Ark. 2007) (“[I]t is evident, from the property owners’ claims and from the sheer nature of a claim for private nuisance, that individual issues exist in the instant case as to whether and to what extent Georgia

– Pacific’s operation of its waste water treatment system caused consequences to, and constituted an unreasonable interference with, the property owners’ use and enjoyment of their property.”). 5

5 Courts have also declined to certify nuisance pollution cases when the plaintiffs failed to show a method of proving classwide harm. See, e.g. , Burkhead v. Louisvill e Gas & Elec. Co. , 250 F.R.D. 287, 299 (W.D. Ky. 2008) (“Plaintiff s have alleged that Defendant’s operations result in extensive emissions, but what remains missing is any evidence that the cause of the entire class’s damages could be determined in a single proceeding.”); St. Joe Co. v. Leslie , 912 So. 2d 21, 24 (Fla. D ist. Ct. App. 2005) (“ Appellees failed to prove how the class represen tatives could prove their own .

. . nuisance claims, thereby proving the claims of the unnamed members.”); Ga

. - Pac

. Consumer Prods., LP v. Ratner , 762 S.E.2d 419, 423 (Ga. 2014) (reversing order to certify air pollution class because members had not presented “evidence by which the plaintiffs might be able to prove [ harm ] on a classwide basis” such as scientific evidence about how much pollution mo ved through the air). By contrast, the plaintiffs here have offered expert testimony and a common method for proving their claims against GPC

.38 GPC relies on a decision by the Eighth Circuit filed after the class
certification order here. See Ebert, 823 F.3d at 475, 481. In Ebert , the district court certified a class action against General Mills brought by neighboring property owners arising from groundwater contamination

. Id. at 476. The defendant had disposed of hazardous chemicals by burying perforated drums of trichloroethylene (TCE) on its land. Id . at 475. “[T]he plaintiffs claim[ed]

. . . TCE vapors migrated into the surrounding residential area, threatening the health of the residents and diminishing the value of their property.” Id. The Eighth Circuit panel agreed the “standardized conduct of alleged contamination and the remedies sought by the class are common to all plaintiffs.” Id. at 478.
Yet the appellate court reversed the certification order after concluding
that i ndividual issues predominated : To resolve liability there must be a determination as to whether vapor contamination, if any, threatens or exists on each individual proper ty as a result of General Mills’ actions, and, if so, whether that contamination is wholly, or actual ly, attributable to General Mills in each instance. Accordingly, accompanying a determ ination regarding General Mills’ actions, there likely will be a property

- by

- property assessment of additional upgradient (or other) sources of contamination, whether un ique conditions and features of the property create the potential for vapor intrusion, whether (and to what extent) the groundwater beneath a property is contaminated, whether mitigation has occurred at the property, or whether each individual plaintiff ac quired the property prior to or after the alleged diminution in value.

Id. at 479

. Ebert is distinguishable. Tracking the migration of contaminated groundwater in that case involved more complex variables than GPC’s smokestack pollution blanketing its Mu scatine neighborhood with airborne particulates. And the Ebert plaintiffs sought recovery for
diminution in property values, raising valuation issues unique to each39
property. Id. at 479; see also Mel Foster Co. Props., Inc. v. Am. Oil Co. , 427 N.W.2d 171 , 176 (Iowa 1988) (noting measure of damages in nuisance case for diminution of value is “the market value of [the] property immediately before contamination and the market value of that property after the contamination”). By contrast, the class members h ere are not seeking recovery for any reduction in their property values, but rather for their shared experiences with GPC’s smoke, odor , and dust.
W e hold that the district court did not abuse its discretion in rejecting GPC’s predominance objection to c lass certification. O ur class action rules do not require that the residents present “common proof on
each element of the claim. Rather, we have repeatedly noted that the existence of individual issues is not necessarily fatal to class
certification.” Comes , 69 6 N.W.2d at 322 (quoting Howe , 656 N.W.2d at 289). Individual issues concerning contamination from other sources or the amount of chemicals present on a particular property may affect damage calculations, but such concerns do not overwhelm common issues of liability. GPC’s priority of location is conceded, and c ommon proof will be required on GPC’s course of conduct , its emissions during the relevant time period, its knowledge of emissions, and at what level emissions interfere with a normal pers on in the community’s enjoyment
of his or her property. These common questions of liability are at the
heart of the residents’ claims.
B. Whether Certifying the Class Offends Due Process. We next
address GPC’s contention that the class certification violates its due

process rights . “Civil litigation deprives the litigants of property

— the plaintiff of her cho se in action, the defendant of money damages if it
loses

— and thus must accord the litigants due process of la w.” Newberg § 11:21 (footnote omitted) . “A defendant in a class action has a due40 process right to raise individual challenges and defenses to claims, and a
class act i on cannot be certified in a way that eviscerates this right or
masks individual issues.” Carrera v. Bayer C orp. , 727 F.3d 300, 307 (3d Cir. 2013). Extrapolation raises due process concerns because it provides a full trial, and opportunity to be heard, for some plaintiffs but not for others and, correlatively, because it enables the defendant to contest damage s through individualized affirmative defenses against some plaintiffs but not al l. Newberg § 11:21. GPC asserts the residents’ plan to extrapolate harm to surrounding properties from testimony of twenty to thir ty representative class
members violates due process by masking individual issues. GPC argues it must be allowed to pursue individual factors that might reduce certain class members’ damages, such as the members’ knowledge of the air pollution upon moving to the community. GPC relies on In re Fibreboard Corp. , 893 F.2d 706 (5th Cir. 1990). In Fibreboard , the district court
certified a class of over 3000 asbestos claims. Id. at 707 . To assess damages, it proposed to try a small, limited segment of claims in full, then extrapolate fro m those individualized awards to an omnibus award
for the class. Id. at 708

– 09. From those witnesses, the jury would extrapolate damages to the class as a whole. Id. at 709. The Fifth Circuit, in granting mandamus to prevent trial, recognized that such extrapolation violated the defendant’s rights by masking differences in causation, types of injury, fact of injury, and exposure. Id. at 711.
Fibreboard is inapposite. In Fibreboard , the claims presented were
more diverse than here

. P laintiffs suffer ed different personal injuries, from different causes, over different periods of time. Here , the residents are not claiming personal injuries. Rather, they seek recovery for the41

lo ss of use and enjoyment of their property caused by GPC’s emission s. The district court has not limited the number of witnesses GPC can present, nor its exploration of individual defenses. Moreover, the Supreme Court has indicated inferences from representative proof are permissible in certain circumstances. In Dukes , t he Court rejected the use of testimony from a sample of 120 Wal

- Mart employees because it found all members of the class were not similarly
situated and the plaintiffs lacked evidence the sample was representative. 564 U.S. at 36 7 , 131 S. Ct. at 25 61

. Bu t f ive years later,
in Bouaphakeo , the Court allowed representative evidence compiled by an expert to establish employee’s average donning and doffing time. 577
U.S. at ___, 136 S. Ct. at 1044

– 45 . Explaining this difference, the Court stated,
The underl ying question in Wal

- Mart , as here, was whether the sample at issue could have been used to establish liability in an individual action. Since the Court held that the employees were not similarly situated, none of them could have prevailed in an individua l suit by relying of depositions detailing the ways in which other employees were discriminated against by their particular store manager s
. . . . In contrast, the study here could have been sufficient to sustain a jury finding as to hours worked if it w ere introduced in each employee’s individual action. While the experiences of the employees in Wal

- Mart bore little relationship to one another, in this case each employee worked in the same facility, did similar work, and was paid under the same policy.

. . . [U]nder these circumstances the experiences of a subset of employees can be probative as to the experiences of all of them.

Id. at ___, 136 S. Ct. at 104 8 . We have allowed testimony from community residents in nuisance actions to prove the “normal person”
standard. The plaintiffs plan to call witnesses from throughout the neighborhood

. GPC is free to call additional witnesses. As we have42 already discussed, this class action can proceed in a manner that preserves GPC’s due process rights to contest harm and damages suffered by individual class members.
If proof of i ndividual defenses becomes unmanageable, the district

court has discretion to bifurcate the trial, create additional subclasses, or decertify the class

. [B]ifurcation enabl es the common issue of liability to be resolved in an aggregate proceeding but reserves the assessment of individual damages for some subsequent, more individualized processing. Courts have therefore held that bifurcation assists certification by respondi ng to due process conce rns. Newberg § 11:10 (footnote omitted)

. At this stage of the case, GPC has not shown the class certification order violates its due process rights.
IV
. Disposition. For these reasons, we affirm the district court’s order cer tifying
th is class action.
DISTRICT COURT CLASS CERTIFICATION ORDER AFFIRMED. All justices concur except Appel, J., who concurs specially.43

# 15

– 1942, Freeman v. Grain Processing Corp.
APPEL , Justice (concurring specially). I concur in the generally thorough majority opinion in this case. I write separately , however, to emphasize the difference between Iowa law and federal law on the question of class certification. Iowa is one of two states that have adopted a version of the
Uniform Class Actions Act. Thomas D. Rowe, Jr., State and Foreign
Class

- Actions Rules and Statutes: Differences from

— and Lessons for?

— Federal Rule 23 , 35 W. St. U. L. Rev. 147, 150 (2007)

. One of the purposes of the Uniform Class Actions Act was to create a more generous standard for class certification because “federal courts have severely restricted the availability of class actions in their forum.” Irving Scher, Opening State Courts to Class Actions: The Uniform Class Actions Act , 32 Business Lawyer 75, 86 (1976). Consistent with the Uniform Class Actions Act upon which they are based, Iowa courts have consistently
stated “ [ o ] ur class

- action rules are remedial in nature and should be
liberal ly construed to favor the maintenance of class actions.” Comes v

. Microsoft Corp. , 696 N.W.2d 318, 320 (Iowa 2005); accord Anderson Contracting, I nc. v. DSM Copolymers, Inc. , 776 N.W.2d 846, 848 (Iowa 2009); Lucas v

. Pioneer, Inc

. , 256 N.W.2d 167, 175 (Iowa 1977). In light of this legislative history and our caselaw, federal class action precedent is of limited value in determining class certification under Iowa law.