HARTLE et al v. FIRSTENERGY GENERATION CORPORATION

Filing 171

MEMORANDUM OPINION regarding Daubert motions to exclude testimony of Michael Gochfeld, Peter Valberg, James Smith, and Allister Vale. Signed by Chief Judge Joy Flowers Conti on 3/5/2014. (blr)

IN THE UNITED STATES DISTRICT COURT
FOR THE WESTERN DISTRICT OF PENNSYLVANIA
Hartle et al.,
Plaintiffs,
Civil Action No. 08-1019

v.
FirstEnergy Generation Corp.,
Defendant.

MEMORANDUM OPINION
CONTI, Chief District Judge

I.

Introduction
Before the court are expert challenges filed by plaintiffs Michael and Jessica

Hartle and their minor daughter, “GH” (collectively “plaintiffs”), and defendant
FirstEnergy Generation Corporation (“FirstEnergy” or “defendant”). This case
involves FirstEnergy’s Bruce Mansfield Power Plant (“Bruce Mansfield”), a coal-fired
electric generating facility located along the Ohio River in Shippingport,
Pennsylvania. The plaintiffs allege that on July 22, 2006, Bruce Mansfield discharged
air pollution in the form of “black rain,” a dark-colored sooty material that fell to the
ground near the plant. The plaintiffs allege that GH was playing outside during the
black rain event and was exposed to toxins—particularly thallium, arsenic, and other
hazardous metals—in the sooty residue, which caused her to suffer alopecia1 and
other adverse health effects.
The parties conducted extensive fact and expert discovery in this case and two
other cases consolidated for discovery purposes (Patrick v. FirstEnergy Generation
Corp., Civil No. 08-1025, and Price v. FirstEnergy Generation Corp., Civil No. 081

Alopecia is a medical condition involving hair loss. In this case, GH became
completely bald, a condition known as alopecia totalis. (Gehris Dep. 23:23–25:1,
June 19, 2009, ECF No. 108-15.)

1

1030). This memorandum opinion addresses the parties’ motions to exclude the
expert testimony of Michael Gochfeld, MD (“Gochfeld”), ECF No. 106; Peter Valberg,
PhD (“Valberg”), ECF No. 120; James S. Smith, PhD (“Smith”),2 ECF No. 102; and
Allister Vale, PhD (“Vale”), ECF No. 122. These experts opine on toxicology and
medical issues related to the causation of GH’s medical conditions. The motions to
exclude these experts are fully briefed, and the court heard testimony and argument
on October 16, 2013.

II.

Legal Standards
Federal Rule of Evidence 702 governs the admissibility of expert testimony and

states:
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 specialized
knowledge will help the trier of fact to understand the
evidence or to determine a fact in issue;
(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 reliably applied the principles and
methods to the facts of the case.
FED. R. EVID. 702. Under the seminal case of Daubert v. Merrell Dow
Pharmaceuticals, Inc., 509 U.S. 579 (1993), district courts must act as gatekeepers to
3

“ensure that any and all scientific testimony or evidence admitted is … reliable.” Id. at
2

Smith also rendered opinions, challenged by defendant, in the Patrick and Price
cases. These motions are not at issue in the present memorandum opinion.

3

While Daubert applied exclusively to scientific testimony, see Daubert, 509 U.S. at
590 n.8, the Supreme Court subsequently extended the district court’s gatekeeper
function to all expert testimony. Kuhmo Tire Co. v. Carmichael, 526 U.S. 137, 147
(1999).

2

589. The United States Cou of Appea for the Th Circuit explained th Rule 702
urt
als
hird
hat
“embodies a trilogy of restr
rictions” tha expert test imony must meet for ad
at
dmissibility:
qualification, reliability and fit. Schneid ex rel. Es
r
d
der
state of Schneider v. Frie 320 F.3d
ed,
396, 404 (3d Cir. 2003). The party off
T
fering the expert testimony has the burden of
e
establishing each of these requiremen by a prep
nts
ponderance of the evid
dence. In re
63
999).
TMI Litig., 193 F.3d 613, 66 (3d Cir. 19

A. Qualification
An expert witness’s qualification stems fro his or her “knowl
om
ledge, skill,
experience, training, or ed
ducation.” FED. R. EVID. 702. The w
witness ther
refore must
have “specialized expertis ” Schneid
se.
der, 320 F.3 d at 405. The court of appeals
interprets the qualification requireme “‘liberal ly,’ holding that ‘a broa range of
n
ent
ad
knowledge, skills, and train
ning qualify an expert as such.’” Cal
lhoun v. Yam
maha Motor
Corp., U.S.A., 350 F.3d 316 321 (3d Cir. 2003) (quoting In re Paoli R.R. Yard PCB
6,
C
.
Litig., 35 F.3d 717, 741 (3d Cir. 1994) When e valuating an expert’s qua
d
)).
alifications,
district courts should not insist on a ce
i
ertain kind of degree or background Robinson
d.
v. Hartzell Propeller Inc., 326 F. Supp. 2d 631, 667 (E.D. P 2004). A expert’s
Pa.
An
qualifications are determin with resp to each matter addressed in th proposed
ned
pect
he
testimony. Calhoun, 350 F. at 322 (“ expert may be generally qualifie but may
.3d
“An
ed
lack qualifications to testif outside hi area of e xpertise.”). “While the background,
fy
is
education, and training may provide an expert with genera knowledge to testify
m
al
about general matters, mor specific knowledge is required to support mo specific
re
k
s
ore
opinions.” Id.

B. Reliability
In Daubert, the Supr
reme Court stated that the district court’s gatek
keeper role
requires “a preliminary assessment of whethe r the reasoning or methodology
a
underlying the testimony is … valid and of whet her the reasoning or methodology
i
a
properly can be applied to the facts in issue.” Daubert, 509 U.S at 592–93. While the
S.
Court noted in Daubert th district courts were permitted t undertak a flexible
hat
to
ke
3

inquiry into the admissib
bility of exp
pert testimony under R
Rule 702, th court of
he
appeals has enumerated the following eight factors that a district court may examine:
e
e
y
1. whether a method consists of a testable hypothesis;
c
2. whether the method has been subjected to peer review ;
d
3. the known or poten rate of error;
ntial
e
4. the existence and maintenance of standard controlling the techni
m
e
ds
ique’s
operation;
5. whether the method is generally accepted;
d
y
6. the relationship of the tech
o
hnique to methods which have been
established to be rel
liable;
7. the qualifications of the expert witnes testifying based on the
ss
n
methodology; and
8. the non-judicial use to which the method has been put.
es
t
In re Paoli R.R Yard PCB Litigation , 35 F.3d 717, 7 n.8 (3d Cir. 1994) (
L
742
(“Paoli II”).
This list of fac
ctors is a “c
convenient starting poin but is “neither exha
s
nt,”
austive nor
applicable in every case.” Kannankeril v. Terminix Int’l, Inc., 128 F.3d 802, 806–07 (3d
K
v
Cir. 1997).
Under these factors, experts are not per mitted to engage in a “
e
“haphazard,
intuitive inquiry,” but must explain the research and methodo
t
e
ology they em
mployed in
suf
fficient detail in order to allow the ot
o
ther party’s e
expert to test that hypot
thesis. Oddi
v. Ford Motor Co., 234 F.3 136, 156 (3d Cir. 2000). Where an expert f
3d
fails to use
standards to control his or her analysis “no ‘gateke
s,
eeper’ can assess the rela
ationship of
[the expert’s] method to other metho known to be reliabl and the n
m
o
ods
le
non-judicial
uses to which it has been pu ” Id. at 15
ut.
58.
“The evidentiary req
quirement of reliability is lower than the merits s
f
standard of
correctness.” Paoli II, 35 F.3d at 744. “A long as an expert’s sc
As
cientific testi
imony rests
upon ‘good grounds, based on what is known,’ it should be tested by the adversary
s
e
process—competing exper testimony and activ cross-examination—r
rt
y
ve
rather than
exc
cluded from jurors’ scru
utiny for fea that they will not grasp its comp
ar
plexities or
4

satisfactorily weigh its inad
dequacies.” United States v. Mitchell, 365 F.3d 215, 244 (3d
U
Cir. 2004) (quoting Ruiz-T
Troche v. Peps Cola of P. R. Bottling Co., 161 F.3d 77, 85 (1st
si
d
Cir. 1998)).

C. Fit
The Rule 702 require
ement that testimony “h
help the trier of fact to u
understand
the evidence or to determ
mine a fact in issue” is called the “fit” requir
rement. Fit
requires that there be a “connection between the s cientific research or test result to be
presented and particular disputed fact
d
tual issues in the case.” Paoli II, 35 F at 743.
n
F.3d
“‘Fit is not alw
ways obvious and scient
s,
tific validity for one purpose is not necessarily
scientific valid for other unrelated purposes.’” Id. (quotin Daubert, 509 U.S. at
dity
r,
ng
591). The standard for fit is “not that high,” although it is “higher than bare
f
t
relevance.” Id. at 745.

III.

Discussion
A. Defendant’s Mo
otion to Pre
eclude the Expert Opinions of Gochf
feld
Plaintiffs’ expert Go
ochfeld is a physician. He examined GH in 2008 and

concluded that her hair los was caused by exposure to thallium and arsen In 2012,
t
ss
d
m
nic.
Gochfeld reviewed his file and additio
onal docume
ents that became availab after the
ble
original examination and prepared an expert repo dated July 12, 2012 (“Gochfeld
p
n
ort
Rep.”). Gochfeld opined th “chemica exposure from soot, including th
hat
al
hallium and
arsenic, were responsible for [GH’s] alopecia.” (G
a
Gochfeld Rep. 2, ECF N 108-1.)
No.
Gochfeld submitted a rebu
uttal report dated Dece mber 3, 2012 (“Gochfeld Rebuttal
Rep.”), addressing the reports submitted by other ex
xperts.
Defendan challenges the reliabili of Gochfeld’s opinions on three g
nt
ity
grounds: (1)
Gochfeld failed to determine the level of thallium exposure needed to cau alopecia
d
use
and the dose received by GH; (2) Gochfeld fail ed to rule out alopecia areata, an
d
a
autoimmune condition, as the cause of GH’s hair loss and failed to a
s
account for

5

conditions inconsistent with thallium poisoning; and (3) Gochfeld solely relied upon
the temporal relationship between GH’s exposure and the hair loss.

1. No Calculation of Dose of Thallium Received by GH
Defendant argues that a determination of dose received is a requirement for
proving causation in a toxic-tort case. (ECF No. 107, at 8 (citing McClain v. Metabolife
Int’l, Inc., 401 F.3d 1233, 1241 (11th Cir. 2005).) Gochfeld admitted that he did not
calculate the dose of thallium received by GH and could not do so based on “the very
meager information available.” (Gochfeld Dep. 146:18–147:1, Feb. 19, 2013, ECF No.
108-5.) Gochfeld did not offer an opinion about the threshold dose of thallium
required to cause alopecia in humans. (ECF No. 148, at 10.) Plaintiffs respond that
there is no requirement that a plaintiff present evidence of the precise dose received
in every case. (Id. at 9.) For example, plaintiffs point out, where concentrated pool
chemicals spilled on to a plaintiff ’s face, the inability of the medical expert to identify
the specific dose did not render his opinion unreliable. Best v. Lowe’s Home Ctrs., Inc.,
563 F.3d 171, 178 (6th Cir. 2009).
This case is not as obvious as chemicals spilled on a face. Nevertheless,
Gochfeld’s failure to identify a precise thallium exposure does not render his opinions
inadmissibly unreliable. In Kannankeril v. Terminix International, Inc., 128 F.3d 802
(3d Cir. 1997), the district court excluded the plaintiffs’ medical expert for failing to
determine the plaintiffs’ exact degree of exposure to pesticide. Id. at 808. The Court of
Appeals for the Third Circuit reversed, finding that the expert had sufficient
knowledge of exposure from his review of the defendant’s pesticide application
records and holding that “all factual evidence of the presence of the chemicals in the
residence should be relevant in forming an expert opinion of causation.” Id. at 808–
09. The expert’s lack of direct test results for the dose received was a matter for the
trier of fact to weigh in determining the expert’s credibility. Id. at 809 (admonishing

6

trial judges to “be careful not to mistake credibility questions for admissibility
questions”).
Gochfeld performed a “differential diagnosis,” a technique that involves ruling
out alternative causes for symptoms “by a systematic comparison and contrasting of
the clinical findings.” Id. at 807 (internal quotation marks omitted). Differential
diagnosis involves “the testing of a falsifiable hypothesis[,] … has widespread
acceptance in the medical community, has been subject to peer review, and does not
frequently lead to incorrect results.” Paoli II, 35 F.3d at 758.
Gochfeld heavily relied on the timing of the hair loss relative to the alleged
thallium exposure. In certain circumstances, “the reporting of symptoms can be in
itself diagnostic of exposure to a specific substance, particularly in evaluating acute
effects.” Bernard D. Goldstein & Mary Sue Henifin, Reference Guide on Toxicology, in
REFERENCE MANUAL ON SCIENTIFIC EVIDENCE 633, 671 (3d ed. 2011). Alopecia is a
strong indication of thallium exposure. Defendant’s expert Vale testified that
“alopecia develops in virtually everyone who is poisoned with thallium.” (Vale Dep.
115:17–18, Apr. 19, 2013, ECF No. 148-9.) Gochfeld found that GH’s hair loss began
two or three weeks after the black rain event. (Gochfeld Rep. 2, ECF No. 108-1.) In
light of the strong temporal connection between exposure and symptoms and
Gochfeld’s differential diagnosis ruling out alternative causes, his inability to calculate
a thallium dose for GH does not render his diagnosis inadmissibly unreliable.

2. Failure to Exclude an Autoimmune Cause for the Hair Loss and Account
for Conditions Inconsistent with Thallium Poisoning
Defendant argues that Gochfeld failed to consider the conclusions of other
physicians who treated or examined GH. (ECF No. 107, at 10.) Dr. Michael Speca, Dr.
Robert Stiegel, Dr. Matthew Zirwas, and Dr. Robin Gehris each diagnosed GH with
alopecia areata, an autoimmune condition. Defendant argues that Gochfeld did not
adequately respond to this alternative hypothesis, making his differential diagnosis
scientifically unreliable. (Id. at 11.) Although “[a] medical expert’s causation conclusion
7

should not be excluded because he or she has failed to rule out every possible
alternative cause of a plaintiff ’s illness,” the expert must rule out plausible alternative
causes. Heller v. Shaw Indus., Inc., 167 F.3d 146, 156 (3d Cir. 1999).
Gochfeld noted that an autoimmune condition is a plausible cause for GH’s hair
loss, but he adequately considered it and ruled it out. (Gochfeld Rebuttal Rep. 5, ECF
No. 108-18.) Gochfeld cited a peer reviewed study indicating that alopecia areata is
rare before age three (GH was thirty-four months old at the onset of the hair loss).
(Id.) Tests found that GH had no biomarkers for an autoimmune condition. (Id. at 8.)
These factors, combined with the onset of symptoms at the time consistent with a
toxic cause, led Gochfeld to rule out an autoimmune basis. (Id.) The disagreement of
other experts is a matter for the jury to resolve. Gochfeld’s opinion will not be
excluded on this basis.
Defendant argues that, aside from hair loss, GH did not experience symptoms of
thallium poisoning, which typically include severe abdominal pain, vomiting, nausea,
bloody diarrhea, and discolored lines on the nails of fingers and toes. (ECF No. 107,
at 14; see Gochfeld Dep. 59:10–61:14, ECF No. 108-5.) Additionally, defendant argues
that GH’s pattern of hair regrowth—starting two years after it was first lost and not
completely regrown for five or six years—was inconsistent with a diagnosis of
thallium poisoning. (ECF No. 107, at 15–16.) Plaintiffs point to evidence that GH’s
hair began regrowing a year and a half after the alleged exposure, which is consistent
with thallium toxicity. (ECF No. 148, at 16; Gochfeld Rep. 2, ECF No. 108-1.) This
disputed fact is for the jury to resolve. The lack of additional symptoms is a matter of
weight, not admissibility.

3. Reliance on the Temporal Relationship Between Exposure and Symptoms
Defendant argues that Gochfeld’s opinion is unreliable because it relies solely on
the temporal relationship between the alleged exposure and GH’s hair loss. (ECF No.
107, at 16.) This argument is supported by case law. See Buzzerd v. Flagship Carwash

8

of Port St. Lucie, Inc., 669 F. Supp. 2d 514, 530 (M.D Pa. 2009) (excluding an opinion
F
5
D.
that rested “almost exclu
usively on the tempor al connection” between plaintiffs’
t
n
reported symptoms and all
leged exposu
ure); Roche v. Lincoln Prop. Co., 278 F. Supp. 2d
744, 764 (E.D. Va. 2003) (“An opinio based primarily, if n solely, on temporal
on
not
n
proximity does not meet Daubert stand
s
D
dards.”).
In Heller, the Court of Appeals fo the Third Circuit affirmed the exc
o
or
clusion of a
causation opinion “largely” based upon the temporal relationship be
u
etween the
plaintiff ’s illness and the in
nstallation of defendant’s product. H
o
Heller, 167 F at 157–
F.3d
58. The court of appeals noted that a stronge r temporal link could support a
s
t
conclusion of causation. Id. at 158 (“[W
W]hen the temporal relationship is st
trong and is
part of a standard differen
ntial diagnos it would fulfill many of the Da
sis,
d
aubert/Paoli
factors.”). In this case, the link betwee thallium t
en
toxicity and hair loss is strong, the
temporal proximity betw
ween sympto
oms and t he alleged exposure su
upports the
dia
agnosis, and other cause have been ruled out as part of a differential diagnosis.
es
n
l
Gochfeld’s opinions meet the standa for ad missibility. Defendant’s motion to
t
ard
preclude Gochfeld’s opinion will be de
ns
enied.

B. Plaintiffs’ Moti to Limit the Testimo of Valberg
ion
t
ony
Valberg, a toxicologi submitte an exper report dated Octobe 22, 2012
ist,
ed
rt
er
(“Valberg Rep.”). Valberg calculated GH’s potentia exposure to thallium b
c
al
based upon
the parties’ air dispersion models and a chemical analysis of the black ra residue.
d
ain
Based upon information th GH eng
hat
gaged in pica behavior—the eating o nonfood
a
of
sub
bstances such as dirt—
—Valberg ap
pplied the a
analysis of a U.S. Env
vironmental
Protection Agency repor entitled “World Tr ade Center Indoor En
rt
nvironment
Assessment” (“WTC Asse
essment”). (V
Valberg Re p. 6, ECF No. 121-2.) The WTC
Assessment contains input parameters for pica ac tivity, which Valberg con
t
nservatively
applied. (Id. at 7.) Valberg calculated GH’s “reasona maximum dose” of thallium to
c
G
able
be 0.00057 mg (or 0.00004 mg/kg). (I at 14.) Valberg compared this to the lowest
44
Id.
o

9

recorded dose of thallium known to cause alopecia, 310 mg or 4.4 mg/kg, which is
approximately 100,000 times larger than GH’s maximum dose. (Id.) Valberg
concluded “there is no evidence” that pollution from Bruce Mansfield caused GH’s
alopecia. (Id. at 16.)
Plaintiffs attack Valberg’s report on three grounds. First, there is no scientifically
known minimum threshold dose of thallium that causes alopecia in humans, and the
310 mg referenced by Valberg is “misleading, unfairly prejudicial and entirely
speculative.” (ECF No. 121, at 6–7.) Second, Valberg calculated exposure solely based
upon hand-to-mouth ingestion of soil and ignored dermal absorption and inhalation
as exposure pathways. (Id. at 8.) Third, the WTC Assessment was designed for indoor
use, and has not been validated for outdoor use. (Id. at 10–11.) The court concludes
that these arguments either lack merit or are matters of credibility or weight, not
admissibility. Valberg’s opinions meet the threshold for admissibility.
With respect to the dose of thallium required to cause alopecia, Valberg’s report
identifies 310 mg as the “lowest estimate of actual thallium intake (as opposed to an
indirect measurement of blood or urine)” known to cause alopecia in an adult.
(Valberg Rep. 14, ECF No. 121-2.) The court does not find this statement misleading,
speculative, or unfairly prejudicial. Valberg’s report does not suggest that this amount
“is the lowest ‘required’ dose for alopecia,” as asserted by plaintiffs. (ECF No. 121, at
6.) Plaintiffs can elicit testimony regarding the limitations of the 310 mg figure on
cross-examination, reducing any risk for confusion by the jury.
Valberg’s failure to include inhalation and dermal absorption pathways in his
exposure estimate does not render his opinion inadmissibly unreliable. Valberg
concluded that ingestion, particularly for a pica child, would be the “largest
contributor to dose.” (Valberg Rep. 5, ECF No. 121-2.) Due to the size of the particles,
only a “very small” amount of material could be expected to reach the body by
inhalation. (Id.) Because thallium is an inorganic metal, there would be little dermal

10

absorption. (H Tr. 105:2
Hr’g
2–15, Oct. 16 2013, ECF No. 162.) The WTC A
6,
Assessment
did not consider dermal ab
d
bsorption of metal to b e a relevant exposure pa
f
athway. (Id.
105:12–13.) The court find that Valbe exclude d inhalation and dermal absorption
ds
erg
after a reasoned analysis Whether Valberg’s failure to include these exposure
s.
a
e
pathways leads to a faulty conclusion is a credibi
y
ility determination for t jury, or
the
goes to the weight to be af
fforded to th testimony by the jury and is not a matter of
he
y,
adm
missibility.
The WTC Assessmen was design for ind oor dust exp osure. (Valberg Rep. 6.,
nt
ned
ECF No. 121-2.) Valberg te
estified that
f
[t]he heart of the [WTC Assessment] method is child
behavior, how do they tou surfaces and how they touch
uch
s
their mouths subsequentl to that. … Whether [GH] is
ly
indoors or out
tdoors is re
eally not rele
evant to her behavior.
And, in fact, if anything, indoor exp
,
posures typically have
greater contact of children with surf aces and children with
t
n
their mouths.
(Hr’g Tr. 117:18–118:1, EC No. 162.) Valberg als made a n
CF
)
so
number of co
onservative
estimates with respect to GH’s pica behavior, doubling the fraction o material
of
transferred from surface to skin and doubling the frequency of hand
d
d-to-mouth
eve
ents. (Valberg Rep. 14, ECF No. 121-2.) The court concludes that the WTC
Assessment is sufficiently reliable in this cont
y
n
text in light of the co
onservative
approaches testified to by Valberg. The jury can c onsider the application o the WTC
V
e
of
Assessment in weighing Va
alberg’s testim
mony.
Plaintiffs’ motion will be denied.
l

C. Defendant’s Mo
otion to Pre
eclude the Te
estimony of Smith
Smith prepared an expert report dated De cember 3, 2012 (“Smith Rep.”), to
t,
h
rebut the report submitted by Valberg. Smith relie d on the work of Jeffery F
Foran, who
prepared an expert report for plaintiffs but subse quently withdrew from th case due
f
s,
he
to a change in his emplo
oyment. (Sm
mith Rep. 2, 7, ECF N 104-4.) Smith also
No.
reviewed field notes and deposition te
d
estimony. (I at 2.) Smith criticize Valberg’s
Id.
ed
11

report on a variety of grounds, particularly Valberg’s use of the WTC Assessment and
failure to consider the inhalation and dermal absorption pathways, which Smith
opined “are likely to significantly add to [GH’s] arsenic and thallium exposure.” (Id. at
6.) By including a dermal absorption pathway, Smith found a six-fold increase from
Valberg’s estimated thallium dose. (Hr’g Tr. 8:1–7, Oct. 16, 2013, ECF No. 162.) Smith
calculated an upper and lower bound for GH’s thallium exposure, concluding that it
was between 3.3 mg and 0.02 mg. (Id. at 8:21–10:4.) Smith testified that both the
upper and lower bound figures are within the range that could cause alopecia in
humans. (Id. at 10:17–11:5.) Smith concluded that GH’s alopecia was “more likely
than not … caused by her exposure to thallium in deposited soot.” (Smith Rep. 11,
ECF No. 11-4.)
Defendant challenges Smith’s report on four grounds: (1) Smith lacked the
requisite degree of certainty for his opinions to be admissible; (2) Smith failed to
determine the level of thallium exposure necessary to cause hair loss in humans; (3)
Smith’s attempt to calculate the exposure of GH is unreliable; and (4) Smith failed to
conduct a differential diagnosis and rule out other potential causes of GH’s alopecia.
As set forth below, the court finds that Smith’s testimony meets the threshold for
admissibility.

1. Requisite Degree of Certainty
Defendant points to a number of equivocal statements in Smith’s deposition
testimony. (ECF No. 103, at 4–6.) For example, Smith testified that GH “may have
been” exposed to contaminants. (Smith Dep. 464:17–20, ECF No. 104-6.) He stated, “I
don’t know that we have the ability to assess accurately the exposure of [GH] to those
contaminants after the fact.” (Id. at 464:20–23.) Smith testified that thallium “could
have caused” GH’s hair loss. (Id. at 469:15–18.)
In diversity cases, federal courts must apply state law with respect to the degree
of certainty required of an expert opinion. Heller, 167 F.3d at 153 n.4. Under

12

Pennsylvania law, “a doctor can give an opinion on the cause of a plaintiff ’s illness if
he or she can do so with a reasonable degree of medical certainty.” Id. To determine
whether an expert has reached an opinion with the requisite degree of medical
certainty, the court must consider the expert’s testimony in its entirety. Hall v. Babcok
& Wilcox Co., 69 F. Supp. 2d 716, 722 (W.D. Pa. 1999).
After reviewing Smith’s report and testimony as a whole, the court concludes
that the equivocal statements in Smith’s deposition testimony do not render his
opinion inadmissibly uncertain. Smith reached the opinions in his report “to a degree
of scientific certainty.” (Smith Rep. 11, ECF No. 104-4.) Smith testified at the Daubert
hearing that he held his opinions to a reasonable degree of certainty. (Hr’g Tr. 10:25–
11:5, 12:14–14:5, ECF No. 162.) Smith testified that his degree of confidence was
better than fifty percent. (Id. at 11:17–20.) See Hall, 69 F. Supp. 2d at 722 (finding
testimony on the whole “sufficiently firm, certain and unequivocal”).

2. Failure to Determine the Dose of Thallium Needed to Cause Alopecia
Defendant asserts that, although Smith reviewed animal tests, agency studies,
and case studies, his analysis was insufficient on the issue of “thallium effects in
humans from subacute or acute exposure.” (ECF No. 103, at 7.) Defendant quoted the
Court of Appeals for the Eleventh for the proposition that “‘[t]he link between an
expert’s opinions and the dose-response relationship is a key element of reliability in
toxic tort cases.’” McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1241 n.6 (11th Cir.
2005). While the court agrees with this proposition, it notes that the Eleventh Circuit
clarified that “[o]ne should not conclude from this analysis that to pass Daubert
muster an expert must give precise numbers about a dose-response relationship.
Some ambiguity about individual responses is expected.” Id. The expert at issue in
McClain provided no evidence about a dose-response relationship for ephedrine and
gave only vague testimony about individual variations, leaving “a muddle of
ambiguity that undermine[d] his opinions.” Id. at 1241.

13

Smith, on the other hand, did consider the amount of thallium necessary to
cause alopecia in humans. Smith reviewed two animal testing studies that showed
alopecia could develop in rats at thallium intakes of 1.2 mg/kg per day and 0.3 mg/kg
per day. (Smith Rep. 8, ECF No. 104-4.) Smith also considered case studies of
thallium-induced alopecia in humans—the same cases relied upon by Valberg. (Id. at
7, 9.) Any inadequacies in Smith’s testimony due to extrapolating from animal testing
data or applying the case studies may be tested through the adversary process. See
Mitchell, 365 F.3d at 244.

3. Unreliable Methodology in Calculating GH’s Thallium Dose
Defendant argues that Smith’s calculation of GH’s thallium dose is unreliable
because he (1) ignored actual soil sample results, (2) used an exposure period longer
than that supported by the facts, (3) unrealistically assumed that GH ate ten grams of
pure soot per day, (4) improperly assumed that 100 percent of thallium contacted was
absorbed through the skin, and (5) failed to account for clearance of thallium from
the body. Plaintiffs argue that these assumptions were reasonable and based on
Smith’s risk assessment experience. (ECF No. 149, at 13.)
Soil samples from the property where GH was allegedly exposed showed no
detectable levels of thallium. (Hr’g Tr. 41:3–8, Oct. 16, 2013, ECF No 162.) These
samples were taken in November 2011, more than five years after the alleged
exposure. Although Smith testified that thallium metal can persist in soil, (id. at
41:25–42:7), the court does not fault Smith for excluding this data so far removed
from the time of the incident. Plaintiffs reasonably argue that since the soot was
deposited in clumps, it may have been concentrated in some locations and not others.
(ECF No. 149, at 20–21.) The 2011 sampling is not necessarily probative of the
conditions in July 2006.
Defendant challenges Smith’s use of a fourteen-day exposure period, arguing
that it has no basis in the facts and is “essentially random.” (ECF No. 103, at 13.)

14

Smith noted that the washing of surfaces around the property may have acted to
concentrate the deposited metals. (Smith Rep. 3, ECF No. 104-4.) Since thallium does
not degrade in the environment, GH could have been exposed to the contaminants
over an extended period. (Id.) The court finds that Smith’s assumption of a fourteenday exposure has a least some factual basis. Whether a prolonged fourteen-day
exposure is likely is a matter for the jury to determine in weighing Smith’s testimony
in light of the facts surrounding the black rain event and subsequent clean up.
Smith made a number of additional assumptions in reaching his upper-bound
estimate of 3.3 mg of thallium. (Hr’g Tr. 54:22–25, Oct. 16, 2013, ECF No 162.) He
assumed that GH ate ten grams of soot per day, that 100 percent of thallium on the
skin was absorbed, and that no thallium was eliminated or “cleared” from the body
during the exposure period. He admitted that these assumptions were designed to be
“health protective” and produced “an unrealistically high estimate.” (Id. at 69:6–9,
78:10–79:3.) GH’s “actual exposure is likely to be less” than Smith’s upper-bound
estimate. (Id. at 54:25–55:1.) The layers of “health protective” assumptions in the
upper-bound estimate produce an exaggerated result. This upper-bound estimate
could be misleading to the trier of fact and is not helpful.
Smith calculated a lower-bound estimate based upon the WTC Assessment
methodology used by Valberg. (Smith Rep. 7, ECF No. 104-4.) Smith applied the
WTC Assessment methodology with a fourteen-day exposure period and dermal
contact exposure pathway, and he computed a dose 0.02 mg. (Id.) Smith testified that
this lower-bound estimate was still within the range of thallium exposure that could
cause alopecia. (Hr’g Tr. 10:25–11:2, Oct. 16, 2013, ECF No. 162.) Smith may testify
that this estimate is the lower bound and the likely exposure was higher. If the
defendant “opens the door” about the upper bounds, Smith will be able to testify
about the upper bound he reported, although he must acknowledge it is unrealistic.

15

Plaintiffs are not prese
enting Smith to make a medical diagnosis, and h offers no
h
he
suc opinion. Smith is being presen
ch
nted to rebut Valberg a
and to offer a general
r
causation opinion that GH was expose to an “inc
H
ed
creased risk of harm.” (Id at 26:22–
d.
27:16.) Because Smith is offering a ge
o
eneral opinion and not a medical d
diagnosis or
specific causation opinion the court finds his methodology sufficient reliable,
n,
t
tly
sub
bject to the limitations noted.

4. Failure to Conduct a Diff
fferential Di agnosis
Defendan argues tha Smith’s op
nt
at
pinions are inadmissibl because h failed to
le
he
make a differential diagn
nosis by ruli out ot her causes of GH’s alop
ing
pecia. This
argument is moot. Smith is not testif
m
fying as a medical expert, offering a medical
g
dia
agnosis, or opining as to specific cau
usation. Smith is offering a general o
g
opinion that
exposure to thallium incr
reased GH’s risk of harm. (ECF No. 149, at 2 Hr’g Tr.
24;
26:22–27:16, 29:8–10, Oct. 16, 2013, EC No. 162. )
CF

D. Plaintiffs’ Moti to Limit the Testimo of Vale
ion
t
ony
Vale is a medical do
octor and toxicologist who has clinical exper
rience with
thallium poisoning. Based on his ex
d
xperience and review of expert reports and
deposition test
timony, Vale concluded that “there is no objective evidence that [GH]
e
e
was exposed to thallium (o arsenic) in sufficient amount to give rise to alopecia or
or
i
other features.” (Vale Rep. ¶ 94, ECF No. 136-5.) Plaintiffs o
object to Val opinion
le’s
that GH’s exposure to tha
allium was not sufficie nt to cause alopecia be
ecause Vale
testified he does not know the body burden of t hallium need to cause alopecia.4
w
b
ded
e
(ECF No. 123, at 8.)
The problem is that the amount of thallium that causes alopecia in humans is
t
not scientifically known. The court con
T
ncluded in it analysis of the motion to exclude
ts
n

4

“Body burden” is “th total amo
he
ount of the s
substance in the body.” (Vale Dep.
n
41:1–42:9, Apr. 19, 20 ECF No. 123-2.)
013,

16

Gochfeld that the lack of knowledge about this threshold amount does not preclude
an expert opinion that GH’s hair loss was or was not caused by thallium poisoning.
Vale may opine on the typical symptoms of thallium poisoning. (Vale Rep. ¶¶ 83–90,
ECF No. 136-5.) Vale may also offer an opinion, based on his review of the
documents in this case and his experience with thallium poisoning, that GH was not
suffering from thallium poisoning. (Id. ¶ 94.)
Plaintiffs also object to language in Vale’s report vouching for other experts
without independently verifying their analysis. As the court stated on the record at
the hearing on October 16, 2013, the “vouching” language will be stricken from the
report, and Vale will be precluded from offering such testimony. (Hr’g Tr. 184:11–
185:16, Oct. 16, 2013, ECF No. 162.)

IV.

Conclusion
Defendant’s motion to preclude the testimony of Gochfeld will be denied.

Defendant’s motion to preclude the testimony of Smith will be denied in part. Smith’s
testimony will be subject to the limitations set forth with respect to his upper-bound
estimate. Plaintiffs’ motion to limit the testimony of Valberg will be denied. Plaintiffs’
motion to limit the testimony of Vale will be granted in part and denied in part. An
appropriate order will be entered.

Dated: March 5, 2014

/s/ Joy Flowers Conti
Joy Flowers Conti
Chief United States District Judge

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