C.W. Ex Rel. Wood v. Textron, Inc.

In the

United States Court of Appeals

For the Seventh Circuit

____________________

No. 14-3448

C.W. and E.W., by Guardians and Next Friends

ADELE A. WOOD and JASON A. WOOD,

Plaintiffs-Appellants,

v.

TEXTRON, INC.,

Defendant-Appellee.

____________________

Appeal from the United States District Court for the

Northern District of Indiana, South Bend Division.

No. 3:10 CV 87 — Philip P. Simon, Chief Judge.

____________________

ARGUED MAY 18, 2015 — DECIDED AUGUST 26, 2015

____________________

Before KANNE and SYKES, Circuit Judges, and Ellis, District

Judge.*

KANNE, Circuit Judge. Government regulators and scien-

tists agree: exposure to vinyl chloride poses serious health

*TheHonorable Sara L. Ellis, of the United States District Court for the

Northern District of Illinois, sitting by designation.

2 No. 14-3448

risks to humans. Vinyl chloride is a known carcinogen, mu-

tagen, and genotoxin.1 But in what quantity and for how

long must a human—in this case, two infant children—be

exposed to vinyl chloride before those health risks material-

ize? The experts for C.W. and E.W., the minor children of Ja-

son and Adele Wood, attempted to answer these difficult

questions in this toxic-tort case.

Unfortunately for the Woods, their attempts fell short.

The district court excluded each of the appellants’ experts,

observing they did not use reliable bases to support their

opinions. Having excluded the appellants’ experts, the dis-

trict court then granted summary judgment in favor of Tex-

tron. It found that, without the experts’ opinions, the appel-

lants could not prove general and specific causation—

required elements under Indiana law in a toxic-tort case.

Although we disagree with the district court’s rationale re-

garding causation, we nevertheless affirm.

I. BACKGROUND

A. Preliminary History

Textron began operations at its fastener manufacturing

plant in Rochester, Indiana, in 1954. The Torx plant, as it

came to be known, proved to be successful; it remained in

operation through 2006. During its operations, however, the

1 For the sake of clarity (primarily our own), we define scientific terms as

the need arises. This occasion presents such a need. In reverse order: a

genotoxin is a poisonous substance that damages DNA; a mutagen is

something that is capable of causing mutations to DNA; and a carcino-

gen is something that causes cancer. MedicineNet.com Home Page, avail-

able at search.medicinenet.com (last visited Aug. 5, 2015).

No. 14-3448 3

plant released vinyl chloride—a toxic gas. That vinyl chlo-

ride eventually seeped into the ground water, contaminating

nearby residential wells.

One of those wells belonged to the Woods. Both Textron

and the Indiana Department of Environmental Management

performed testing on the Woods’ well. Their tests revealed

varying levels of vinyl chloride—from 5.00 and 8.40 parts

per billion to 8.60 and 9.00 parts per billion.2

Once the Woods learned that this toxic substance had

contaminated their well, they understandably left immedi-

ately. Jason and Adele believed the health risks to their chil-

dren were simply too high to remain at the Rochester house.

But in the Woods’ opinion, there was more at stake than the

future risk of cancer; there was the present risk of illness.

While living at the Rochester house, C.W. and E.W. experi-

enced gastrointestinal issues (vomiting, bloody stools), im-

munological issues, and neurological issues.

The Woods adopted their son, C.W., when he was eleven

weeks old. He came home on May 11, 2007. The Woods

adopted their daughter, E.W., when she was eleven days old.

She came home on April 25, 2008. Both children were

younger than two years old when the entire family left the

Rochester house in November 2008. Their illnesses coincided

with their time spent in that house.

After the Woods moved from that house, C.W.’s and

E.W.’s health improved. But the parents’ concerns did not

abate. Fearful that vinyl chloride caused C.W.’s and E.W.’s

2The appellants’ experts later estimated that C.W. and E.W. ingested

water contaminated by vinyl chloride at 3 parts per billion.

4 No. 14-3448

conditions (and mindful of the known cancer risks), Jason

and Adele sued Textron on behalf of their children in Fulton

County Circuit Court. There, they advanced a three-count

complaint, alleging negligence, negligence per se, and negli-

gent infliction of emotional distress.3 The crux of these Indi-

ana tort-law claims was that Textron exposed C.W. and E.W.

to vinyl chloride, which caused their illnesses and substan-

tially increased their risk of cancer and other adverse health

effects. Just one week after the filing of the complaint, Tex-

tron successfully removed the case to federal court. 28 U.S.C.

§§ 1332, 1441, 1446. The appellants then filed a Second

Amended Complaint, this time in federal court, to add a

fourth count for willful and wanton misconduct.

The case proceeded through discovery and the marshal-

ing of experts until, nearly four years after the appellants

filed their original complaint, Textron filed a motion in

limine to exclude the appellants’ three expert witnesses. As

we noted above, that motion was successful; the district

court granted it in its entirety. The district court then found

that, without the experts, the appellants could not prove

general or specific causation. It granted summary judgment

in favor of Textron on all of the appellants’ claims.

Before we turn our attention to the experts, we note that

there are a number of contested facts that are not at issue in

this appeal. For example, this appeal is not about whether, or

with what frequency, Jason and Adele used bottled instead

of tap water to make formula for their infant children. Nor is

3 In their Second Amended Complaint, the appellants added a fourth

count for willful and wanton misconduct.

No. 14-3448 5

this appeal about whether Jason and Adele’s reverse-

osmosis-water-filtration system sufficiently guarded the

children against unacceptable levels of vinyl chloride.

Instead, this appeal is about whether the district court

abused its discretion in excluding the appellants’ experts

based on the reliability of their methodology, and if it did not

abuse its discretion, whether we should affirm its grant of

summary judgment in favor of Textron. See Anderson v. Liber-

ty Lobby, Inc., 477 U.S. 242, 248 (1986) (“Only disputes over

facts that might affect the outcome of the suit under govern-

ing law will properly preclude the entry of summary judg-

ment.”).

B. The Experts

Because our jurisdiction is based on diversity of citizen-

ship, we apply federal procedural law and state substantive

law. Allen v. Cedar Real Estate Grp., LLP, 236 F.3d 374, 380 (7th

Cir. 2001) (citing Erie R.R. v. Tompkins, 304 U.S. 64, 78 (1938)).

The parties do not dispute that Indiana substantive law ap-

plies here. To prove their toxic-tort claims under Indiana law,

the appellants needed to present evidence of general and

specific causation. 7-Eleven, Inc. v. Bowens, 857 N.E.2d 382,

389 (Ind. Ct. App. 2006). General causation examines wheth-

er the substance—in this case, vinyl chloride—“had the ca-

pacity to cause the harm alleged[.]” Id. (emphasis added).

Specific causation, by contrast, examines whether the sub-

stance did, in fact, cause the harm alleged. Id. (emphasis

added). To satisfy this bifurcated burden, the plaintiffs of-

fered the testimony of three experts: (1) Dr. James G.

Dahlgren; (2) Dr. Vera S. Byers; and (3) Dr. Jill E. Ryer-

Powder.

6 No. 14-3448

Both parties agree that these experts are well-qualified.

So we can set that issue to the side. The dispute before us

concerns the reliability of the methodology they employed in

generating their expert opinions. The following section high-

lights their methodology as well as the district court’s ra-

tionale in rejecting it. We begin with Dr. Dahlgren.

1. Dr. James G. Dahlgren

Dr. Dahlgren offered opinions on both general and spe-

cific causation, testifying that, in his judgment, vinyl chlo-

ride can cause and did cause the children’s illnesses. He also

opined that it is highly likely that both children will develop

cancer at some point in the future. He based these opinions

on a differential etiology4 and the fact that levels of vinyl

chloride detected in the appellants’ water supply exceeded

the regulatory levels set by the United States Environmental

Protection Agency (“EPA”) and the Indiana Department of

Environmental Management, among other government

agencies. Dr. Dahlgren also based his opinions on timing, or

in his words, “temporality.” In his view, the fact that the ap-

pellants’ symptoms began after exposure to vinyl chloride

4 “Etiology is the study of causation.” Myers v. Ill. Cent. R.R. Co., 629 F.3d

639, 644 (7th Cir. 2010) (citations omitted). A differential etiology is a

process-of-elimination approach to determining a subject’s cause of inju-

ry. Under this method, an expert “considers all relevant potential causes

of the symptoms and then eliminates alternative causes.” Federal Judicial

Center, Reference Manual on Scientific Evidence 214 (1994). Although the

parties and the district court below refer to this method as a “differential

diagnosis,” that term is really a misnomer. A “diagnosis” is concerned

only about naming the condition or ailment, not establishing its cause.

Id.; see also Happel v. Walmart Stores, Inc., 602 F.3d 820, 825 n.7 (7th Cir.

2010).

No. 14-3448 7

and lessened after removal helps demonstrate that vinyl

chloride is the cause.

As for Dr. Dahlgren’s differential etiology, it is largely

based on the findings (or lack thereof) of other doctors who

have examined C.W. and E.W. To be sure, Dr. Dahlgren con-

ducted physical examinations of both C.W. and E.W. He also

reviewed their medical records. But his differential etiology

is silent on these matters. According to Dr. Dahlgren, “[t]he

scientific studies … demonstrate that damage to the immune

system and the nervous system are known to be caused by

[vinyl chloride] exposure. The thorough evaluations by the chil-

drens’ [sic] doctors have not found an alternative explanation … .”

(emphasis added).

Thus, to accept Dr. Dahlgren’s approach to differential

etiology, one must accept both the scientific studies upon

which Dr. Dahlgren relied and the care taken by the doctors

who examined C.W. and E.W. One must also accept that vi-

nyl chloride should be ruled in as a possible cause at all—a

point we address below.

The district court found Dr. Dahlgren’s methodology to

be unreliable. Citing Cunningham v. Masterwear Corp., 569

F.3d 673, 674–75 (7th Cir. 2009), it first found that Dr.

Dahlgren could not rely on regulatory exceedances to

demonstrate causation. Second, the district court found that

Dr. Dahlgren failed to connect the dots between the scientific

studies that he analyzed and the opinions that he offered.

This is a Joiner problem. In Gen. Elec. v. Joiner, 522 U.S. 136,

138 (1997), the Supreme Court decided to apply the abuse of

discretion standard in reviewing the admission or exclusion

of expert testimony. Affirming the district court’s exclusion

of the experts there, the Court held that “nothing in either

8 No. 14-3448

Daubert or the Federal Rules of Evidence requires a district

court to admit opinion evidence which is connected to exist-

ing data only by the ipse dixit of the expert. A court may con-

clude that there is simply too great an analytical gap be-

tween the data and the opinion proffered.” Id. at 146 (cita-

tions omitted).

In the case before us, the district judge found fault in the

studies that Dr. Dahlgren relied upon. “These articles … fail

to establish that [vinyl chloride] at the dose and duration

present in this case could cause the problems that the

[p]laintiffs have experienced or claim that they are likely to

experience.” C.W. v. Textron, 2014 U.S. Dist. LEXIS 34938, at

*53 (N.D. Ind. Mar. 17, 2014) (“Textron I”). The district judge

then rejected Dr. Dahlgren’s efforts to apply those studies to

this case. Id. at *45 (“The problem again, however, is that …

Dahlgren fails to bridge [the] gap by explaining how he is

able to extrapolate” from those studies).

2. Dr. Vera S. Byers

Like Dr. Dahlgren, Dr. Byers also offered opinions on

both general and specific causation. In her view, exposure to

vinyl chloride can cause and did cause the children’s illnesses.

She traced the children’s exposure to vinyl chloride to their

ingestion of contaminated drinking water, inhalation of va-

pors from bathing, and dermal contact. She then linked that

exposure to their gastrointestinal and immune-system prob-

lems. “The GI problems suffered by both children,” Dr.

Byers wrote, “are consistent with the adverse events associ-

ated with vinyl chloride exposure.” As for the appellants’

immune-system issues, she noted that C.W. and E.W. have a

“very similar pattern of elevated … immune complexes … .

Given that these two children are genetically unrelated, the

No. 14-3448 9

most probable cause of this acquired immune complex com-

plement activation is the Vinyl Chloride exposure.” Dr.

Byers admitted that she knew little about C.W.’s and E.W.’s

family medical histories. She further opined that both chil-

dren are now at a heightened risk level for developing can-

cer.

Like Dr. Dahlgren, Dr. Byers based her opinion, in part,

on a differential etiology. For E.W., Dr. Byers ruled in:

 Congenital structural abnormalities

 Infectious agents including viral

 Degenerative

 Neoplastic

 Toxicity including allergies or in this case exposure

to vinyl chloride

 Metabolic disorders

 Psycho-social issues

She then ruled out each alternative explanation until siding

with vinyl chloride as the specific cause.5 To buttress her

conclusion, Dr. Byers also relied on timing. “Vinyl Chloride

exposure is the most probable cause of [E.W.’s] acute symp-

toms[,]” she opined. “Both children suffered these symp-

toms, most seriously by [E.W.], and both childrens’ [sic]

symptoms subsided when the exposure ceased.”

Once again, to accept Dr. Byers’s approach, one must ac-

cept as relevant the scientific studies upon which Dr. Byers

relied. One must also accept that vinyl chloride should be

5 Dr. Byers’s report does not discuss a differential etiology for C.W.

10 No. 14-3448

ruled in as a possible cause in the first place. The district

court accepted neither. It excluded Dr. Byers based on her

attenuated studies and on her failure to adequately extrapo-

late from them.

3. Dr. Jill E. Ryer-Powder

That brings us to Dr. Ryer-Powder. In her initial report of

August 17, 2011, she addressed the issue of general causa-

tion. Dr. Ryer-Powder claimed that the children’s exposure to

vinyl chloride was “at levels sufficient to cause harm” dur-

ing the applicable time period. She further claimed that this

same level of exposure was “sufficient to present an unac-

ceptable risk of cancer in the future.” Like Dr. Byers, she tied

the appellants’ exposure to ingestion, inhalation, and dermal

contact with vinyl chloride.

For largely the same reasons the district court excluded

the testimony of Doctors Dahlgren and Byers, the district

court also excluded the testimony of Dr. Ryer-Powder. For

example, Dr. Ryer-Powder relied on regulatory exceedances

to formulate her opinion as to causation: “One means by

which the health risks from exposures to chemicals can be

assessed is by comparison to government standards and

regulations.” She found that in this case, the Woods’ drink-

ing water exceeded the standards set by relevant govern-

ment agencies. So in her view, that meant vinyl chloride was

within the realm of possible causes for the appellants’ inju-

ries.

Dr. Ryer-Powder also relied on attenuated studies con-

cerning much higher exposure levels of vinyl chloride than

the ones experienced here. As with Doctors Dahlgren and

Byers, the district court found that she did not do the neces-

No. 14-3448 11

sary work of extrapolating from those studies to C.W. and

E.W. In sum, the district court found that Dr. Ryer-Powder

did not offer a reliable basis to support her proffered opin-

ion.

With this overview in mind, we turn to the merits.

II. ANALYSIS

A. Principles of Law

1. Admissibility of Expert Testimony

Federal Rule of Evidence 702 and Daubert v. Merrell Dow

Pharmaceuticals., Inc., 509 U.S. 579 (1993), govern the admis-

sion of expert testimony in federal courts, even when our ju-

risdiction rests on diversity. See Wallace v. McGlothan, 606

F.3d 410, 419 (7th Cir. 2010) (holding “standards for admit-

ting expert evidence” are “matters that fall on the procedural

side of the Erie divide,” and are thus governed by federal

law) (citations omitted). Daubert itself commenced as a state

court action before it was removed to the Southern District

of California on diversity grounds. 509 U.S. at 582.

Rule 702 provides:

A witness who is qualified as an expert by

knowledge, skill, experience, training, or education

may testify in the form of an opinion or otherwise

if: (a) the expert’s scientific, technical, or other spe-

cialized knowledge will help the trier of fact to un-

derstand the evidence or to determine a fact in is-

sue; (b) the testimony is based on sufficient facts or

data; (c) the testimony is the product of reliable

principles and methods; and (d) the expert has reli-

ably applied the principles and methods to the facts

of the case.

12 No. 14-3448

Fed. R. Evid. 702. Under this rule, expert testimony must not

only assist the trier of fact. It must also demonstrate suffi-

cient reliability—a key concern of the district court below. Id.

The district court is the gatekeeper of expert testimony.6

We stress that “the key to the gate is not the ultimate cor-

rectness of the expert’s conclusions. Instead, it is the sound-

ness and care with which the expert arrived at her opin-

ion[.]”Schultz v. Akzo Nobel Paints, LLC, 721 F.3d 426, 431 (7th

Cir. 2013) (citations omitted).

Daubert provides several guideposts for determining reli-

ability. These guideposts examine (1) whether the scientific

theory has been or can be tested; (2) whether the theory has

been subjected to peer-review and/or academic publication;

(3) whether the theory has a known rate of error; and (4)

whether the theory is generally accepted in the relevant sci-

entific community. Schultz v. Akzo Nobel Paints, LLC, 721 F.3d

426, 431 (7th Cir. 2013) (citing Daubert, 509 U.S. at 593–94).

Importantly, this list is neither exhaustive nor mandatory.

Chapman v. Maytag Corp. (In re Chapman), 297 F.3d 682, 687

(7th Cir. 2002). In some cases it may also be appropriate to

examine, as the district court did here, whether there is “too

great an analytical gap between the data and the opinion

proffered.” Joiner, 522 U.S. at 146. Ultimately, reliability is

determined on a case-by-case basis. Ervin v. Johnson & John-

son, 492 F.3d 901, 904 (7th Cir. 2007).

6 We stress that “the key to the gate is not the ultimate correctness of the

expert’s conclusions. Instead, it is the soundness and care with which the

expert arrived at her opinion[.]”Schultz v. Akzo Nobel Paints, LLC, 721

F.3d 426, 431 (7th Cir. 2013) (citations omitted).

No. 14-3448 13

2. Standard of Review

We employ a two-step standard of review in cases chal-

lenging a district court’s admission or exclusion of the testi-

mony of an expert. First, we review de novo a district court’s

application of the Daubert framework. United States v. Brum-

ley, 217 F.3d 905, 911 (7th Cir. 2000). If the district court

properly adhered to the Daubert framework, then we review

its decision to exclude (or not to exclude) expert testimony

for abuse of discretion. Id. (citing Walker v. Soo Line R.R. Co.,

208 F.3d 581, 590 (7th Cir. 2000)).

B. The District Court’s Adherence to Daubert

The district court properly adhered to the Daubert

framework. The court began its exhaustive review of the ap-

pellants’ three proposed experts by accurately outlining the

Daubert framework. Textron I, 2014 U.S. Dist. LEXIS 34938, at

*6–10. During that outline, the court aptly noted the need for

flexibility in applying Daubert, particularly given “the vari-

ous types of potentially appropriate expert testimony.” Id. at

*9 (citing Deputy v. Lehman Bros., Inc., 345 F.3d 494, 505 (7th

Cir. 2003)) (additional citations omitted).

The court then conducted an in-depth review of the rele-

vant studies that the experts relied upon to generate their

differential etiology. Textron, supra, at *11–53. This careful

approach stands in stark contrast to other cases where we

concluded that courts did not adhere to the Daubert frame-

work. See, e.g., Metavante Corp. v. Emigrant Sav. Bank, 619 F.3d

748, 760 (7th Cir. 2010) (declining to apply abuse of discre-

tion standard where the district court’s one-sentence expert

determination did not satisfy Daubert); Naeem v. McKesson

Drug Co., 444 F.3d 593, 608 (7th Cir. 2006) (same). And on a

14 No. 14-3448

much larger scale, the district court’s approach follows the

same path blazed by the Supreme Court in Joiner. 522 U.S. at

145 (reviewing four epidemiological studies advanced by the

respondent in support of the experts’ conclusions).

According to the appellants, however, the district court

imposed an unachievable requirement that “published liter-

ature exist on the topic of vinyl chloride poisoning in small

children.” It did so, allegedly, despite the Supreme Court’s

admonition that “[p]ublication (which is but one element of

peer review) is not a sine qua non of admissibility.” Daubert,

509 U.S. at 593. The argument that the district court errone-

ously inflated the importance of publications is unavailing.

The appellants misread the district court’s decision. The

district court imposed no such requirement. Instead, it fault-

ed the appellants’ experts for failing to adequately extrapo-

late from the studies they had. To be sure, the district court

also rejected some of the studies as too attenuated from the

appellants’ case. But its rejection of these studies is not tan-

tamount to a requirement of absolute precision. Instead, its

rejection is a recognition of an analytical gap too wide to be

bridged.

Take, for example, the rejected study that analyzed the

carcinogenic effect of vinyl chloride on lab rats.7 Cesare Mal-

toni, et al., Carcinogenity Bioassays of Vinyl Chloride Monomer:

A Model of Risk Assessment on an Experimental Basis, 41 Envtl.

Health Persp. 3 (1981). This study found no statistically sig-

7For the sake of economy, we pull two studies as a representative sam-

ple of the whole—one that deals with animals and one that deals with

humans.

No. 14-3448 15

nificant increase in the number of tumors developed by rats

that were fed 0.03 milligrams of vinyl chloride per kilogram

of bodyweight, (0.03 mg/kg), of vinyl chloride per day (4 to 5

days per week, for 59 weeks), over the control group of rats

that were fed only olive oil. Id. at 16, 21. Remarkably, 0.03

mg/kg is ten times higher than the amount the appellants

allegedly ingested—Dr. Ryer-Powder estimates they ingest-

ed 0.003 mg/kg. And the rats ingested it over a period of

time much longer, at least in rat years, than the children’s

exposure here. Given these facts, Dr. Ryer-Powder’s conclu-

sion that this study shows that C.W. and E.W. are now at an

increased risk of developing cancer was an inferential leap

that the district court was rightly unwilling to make.

This second rejected study, which analyzed the effect of

vinyl chloride on French workers, fares no better. See Steven

J. Smith, et al., Molecular Epidemiology of p53 Protein Mutations

in Workers Exposed to Vinyl Chloride, 147 Am. J. Epidemiology

302 (1998). It drew from a group of adults over the course of

five years. Id. at 302. Yet C.W. and E.W. were exposed to vi-

nyl chloride for less than seventeen and seven months, re-

spectively. As for the levels of exposure, the workers were

divided into exposure groups with the average level set at

3,735 parts per million. Id. at 304. That amount is over 1,000

times greater than the 3 parts per billion to which the chil-

dren were exposed. Nevertheless, Dr. Byers offered it in

support of her opinion that the children are at an increased

risk of developing cancer.

In rejecting these studies and others like it, the district

court properly exercised its role as gatekeeper under Daub-

ert. And the district court acknowledged that studies need

not be precisely analogous to meet the Daubert reliability

16 No. 14-3448

standard. Textron I, supra, at *53 (“I am mindful that an ex-

pert’s opinion does not have to be unequivocally supported

by epidemiological studies in order to be admissible under

Daubert.”) (internal quotations and citations omitted). Ac-

cordingly, it is entitled to deferential review in the second

stage of our analysis.

C. The District Court’s Exclusion of the Experts’ Testimony

Under the second step in our analysis, we apply the

abuse of discretion standard of review. Brumley, 217 F.3d at

911. This standard demands that we “not disturb the district

court’s findings unless they are manifestly erroneous.” Laps-

ley v. Xtek, Inc., 689 F.3d 802, 809 (7th Cir. 2012) (citations

omitted). A deferential standard, it flows from the “wide lati-

tude and discretion” that district courts enjoy when deciding

whether to admit or exclude expert testimony. Ervin, 492

F.3d at 904 (quoting Wintz by & Through Wintz v. Northrop

Corp., 110 F.3d 508, 512 (7th Cir. 1997)).

Here, the district court did not abuse its discretion in ex-

cluding the appellants’ experts. The district court’s primary

concern, and ours on appeal, is the failure of the experts to

connect the dots from the studies to the illnesses endured by

the children. This is the Joiner problem to which we referred

earlier. When a district court “conclude[s] that there is simp-

ly too great an analytical gap between the data and opinion

proffered” such that the opinion amounts to nothing more

than the ipse dixit of the expert, it is not an abuse of discre-

tion under Daubert to exclude that testimony. Joiner, 522 U.S.

at 146. That is what happened here.

The appellants counter with a reasonable argument. They

note that there are no studies available on the impact of vi-

No. 14-3448 17

nyl chloride on children. These studies are unavailable be-

cause of the ethical and moral concerns of introducing toxins

to children. This point is well taken and, we note, the district

court recognized as much. Textron I, supra, at *44 (“[I]t’s

wholly unsurprising that Dahlgren was unable to cite a

study at the precise dose and duration that the … children

were subject to, and nothing in the case law says that he

must do so.”).

But there is a scientific end-around to make up for this

dearth in literature. Scientists have developed computer-

based models to extrapolate from animal data to human sub-

jects, and from high doses to lower doses. Bernard D.

Goldtsein & Mary Sue Henifin, Reference Guide on Toxicology

in Federal Manual on Scientific Evidence 646 (3d ed. 2011)

(“The mathematical depiction of the process by which an ex-

ternal dose moves through various compartments in the

body until it reaches the target organ is often called physio-

logically based pharmokinetics or toxicokinetics.”). Gold-

stein and Henifin recognize that “[a]dvances in computa-

tional toxicology” have facilitated this approach. Id. at 646–

47. The EPA recognizes this and other methods of extrapola-

tion as valid approaches to bridging the gap between the

studies and the general public. U.S. Envtl. Prot. Agency, Toxi-

cological Review of Vinyl Chloride 37–63 (2000) (discussing

methods to extrapolate to low doses and to humans, general-

ly). The appellants’ experts do not mention or refer to this

model of extrapolation.

As for the district court’s rejection of the attenuated stud-

ies themselves, that too falls within the ambit of Joiner. See

522 U.S. at 144–45 (“The studies were so dissimilar to the

facts presented in this litigation that it was not an abuse of

18 No. 14-3448

discretion for the District Court to have rejected the experts’

reliance on them.”). The district court’s decision fell within

its wide scope of discretion, and we will not upset it here.

The district court also found fault in the experts’ differen-

tial etiology because, in its view, the etiology was not relia-

ble. We agree. Dr. Dahlgren’s differential etiology does not

present the reliability that Daubert demands. An example is

helpful here. After ruling in the alternative causes of “inher-

itance, allergy, infection or another poison,” Dr. Dahlgren

then ruled them out because, in his view, these causes

“would have been detected by [the appellants’] doctors and

treated accordingly.”

This approach is not the stuff of science. It is based on

faith in his fellow physicians—nothing more. The district

court did not abuse its discretion in rejecting it. As for Dr.

Byers’s differential etiology, it showcases a rigor missing in

Dr. Dahlgren’s. But it nevertheless contains a fatal flaw: rul-

ing in vinyl chloride as a cause in the first place. Without the

benefit of analogous studies and an acceptable method of

extrapolation, Dr. Byers, like the other experts, is forced to

take a leap of faith in pointing to vinyl chloride as having the

capacity to cause the injuries (and risk of injury) to C.W. and

E.W. The district court ably performed its gatekeeper role in

shielding a jury from this leap.

Dr. Ryer-Powder seeks a boost from government regula-

tion. Recall her report: “One means by which the health risks

from exposure to chemicals can be assessed is by compari-

son to government standards and regulation.” But exceed-

ance of government regulation, as we’ve held before, does

not by itself prove causation. See Cunningham, 569 F.3d at 675

(rejecting this approach because the expert would have to

No. 14-3448 19

know “the specific dangers” that caused the regulatory

agency “to pick the safe level it did”). The district court did

not abuse its discretion in rejecting this methodology. To the

extent the experts also based their opinions on the timing of

C.W.’s and E.W.’s injuries, the district court properly rejected

this methodology as well. Ervin, 492 F.3d at 904–05 (7th Cir.

2007) (“The mere existence of a temporal relationship be-

tween taking a medication and the onset of symptoms does

not show a sufficient causal relationship.”).

In sum, the district court did not abuse its discretion in

excluding the appellants’ experts. We now turn to the final

question on appeal: whether that exclusion was fatal to the

appellants’ toxic-tort case.

D. Summary Judgment

We review a district court’s grant of summary judgment

de novo. Hanover Ins. Co. v. N. Bldg. Co., 751 F.3d 788, 791 (7th

Cir. 2014). Summary judgment is appropriate where the ad-

missible evidence reveals no genuine issue of any material

fact. Fed. R. Civ. P. 56(c).

Given the complex nature of this case, and considering

the appellants make no argument that their case can survive

without the excluded experts,8 this final issue can be re-

solved more simply. With no experts to prove causation—be

it general or specific, see Bowens, 857 N.E.2d at 389—the ap-

8 Before the district court, the appellants’ argued that the opinions of

their treating physicians, Doctors Claude Ruffalo and Jerrod Feldman,

along with Textron’s expert, Dr. Thomas McHugh, were sufficient to es-

tablish causation to survive summary judgment. Textron II, supra, at *5–6.

These arguments are not advanced here.

20 No. 14-3448

pellants cannot prove their toxic-tort case under Indiana law.

Accordingly, we hold that summary judgment in this case

was proper.

Before concluding, however, we must part ways with the

district court’s rationale in granting summary judgment. For

we think the court unnecessarily foreclosed an issue better

left open for future litigants in other cases. The district court

held that differential etiology “cannot be used to support

general causation.” C.W. v. Textron, 2014 U.S. Dist. LEXIS

141593, at *11 (N.D. Ind. Oct. 3, 2014) (“Textron II”). It reiter-

ated this holding in a footnote: “Differential [etiology] is

admissible only insofar as it supports specific causation,

which is secondary to general causation … .” Id. at *12 n.3.

We disagree with the district court’s categorical exclusion

of differential etiology as a method to establish general cau-

sation. Indiana recognizes the important role that differential

etiology plays in toxic-tort cases. Hannan v. Pest Control

Servs., 734 N.E.2d 674, 682 (Ind. Ct. App. 2000). And there

may be a case where a rigorous differential etiology is suffi-

cient to help prove, if not prove altogether, both general and

specific causation.9 The Second Circuit already takes this ap-

9 The Federal Rules of Evidence contemplate using one piece of evidence

to help prove multiple facts in issue. That is why, in appropriate circum-

stances, Rule 105 allows a district court to restrict the scope of evidence

and instruct a jury accordingly. Fed. R. Evid. 105. For this reason, among

others, at least one scholar believes differential etiology “should be ad-

missible on general causation.” Edward J. Imwinkelreid, The Admissibility

and Legal Sufficiency of Testimony About Differential Diagnosis (Etiology): Of

Under–and Over–Estimations, 56 Baylor L. Rev. 391, 406 (2004) (“[A]n etio-

logical opinion expressly addressing specific causation is also relevant to

general causation; a plausible finding that a factor was the cause in a

(continued…)

No. 14-3448 21

proach. See Ruggiero v. Warner-Lambert Co., 424 F.3d 249, 254

(2d Cir. 2005) (“There may be instances where, because of

the rigor of differential diagnosis performed, the expert’s

training and experience, the type of illness or injury at issue,

or some other … circumstance, a differential diagnosis is suf-

ficient to support an expert’s opinion in support of both gen-

eral and specific causation.”). And we adopt it today.

III. CONCLUSION

For the foregoing reasons, the district court properly ap-

plied the Daubert framework to the appellants’ experts. It did

not abuse its discretion in excluding their testimony. With-

out expert testimony to prove general and specific causation,

the appellants could not prove their case. Although we disa-

gree with the district court that differential etiology can nev-

er be used to establish general causation, we nevertheless

AFFIRM its final judgment.

(…continued)

specific case slightly strengthens the inference that the factor in question

is capable of causing illness which the plaintiff developed.”).