REVISED, September 8, 1998
UNITED STATES COURT OF APPEALS
for the Fifth Circuit
_____________________________________
No. 95-20492
_____________________________________
BOB T. MOORE; SUSAN MOORE,
Plaintiffs-Appellants
Cross-Appellees,
VERSUS
ASHLAND CHEMICAL INC.; ASHLAND OIL INC.,
Defendants-Appellees
Cross-Appellees,
AND
DOW CORNING CORPORATION; CDC SERVICES, INC.,
Defendants.
______________________________________________________
Appeals from the United States District Court
for the Southern District of Texas
______________________________________________________
August 14, 1998
Before KING, JOLLY, HIGGINBOTHAM, DAVIS, JONES, SMITH, DUHÉ,
WIENER, BARKSDALE, EMILIO M. GARZA, DeMOSS, BENAVIDES, STEWART,
PARKER, and DENNIS, Circuit Judges.*
W. EUGENE DAVIS, Circuit Judge:
In this toxic tort case, we consider whether the district
court abused its discretion in excluding the opinion of a physician
*
POLITZ, Chief Judge, is recused.
on the causal relationship between Plaintiff's exposure to
industrial chemicals and his pulmonary illness. We find no abuse
of discretion and affirm.
I.
Bob T. Moore was employed as a delivery truck driver for
Consolidated Freightways, Inc. (“Consolidated”), a motor freight
company. On the morning of April 23, 1990, Moore delivered several
drums of chemicals manufactured by Dow Corning Corp. (“Dow”) to
Ashland Chemical Inc.’s (“Ashland”) terminal in Houston. When
Moore opened the back door of his trailer, he smelled a chemical
odor that caused him to suspect that a drum was leaking. Moore and
the Ashland plant manager, Bart Graves, identified two leaking
drums and removed them from the trailer. Mr. Graves contacted Dow
and requested cleanup instructions and a copy of the material
safety data sheet (“MSDS”) for the spilled chemicals. The MSDS
identified the contents of the leaking drum and health hazards
associated with the contents.1 The MSDS stated that the chemical
1
The MSDS provided, in part, as follows:
MATL NAME: DOW CORNING(R) 1-2531 RELEASE COATING
. . . .
SECTION II - HAZARDOUS INGREDIENTS AS DEFINED IN 29 CFR
1910.1200 . . .
TOLUENE . . .
SOLVENT NAPHTHA, PETROLEUM, LIGHT ALIPHATIC . . .
ISOBUTYLISOBUTYRATE
PROPYLENE GLYCOL METHYL ETHER . . .
SECTION III - EFFECTS OF OVEREXPOSURE
. . .
INHALATION: SHORT VAPOR EXPOSURE MAY CAUSE DROWSINESS
AND IRRITATE NOSE AND THROAT. VAPORS MAY INJURE BLOOD,
2
solution included hazardous ingredients, most notably Toluene. It
warned that depending upon the level and duration of the exposure
to fumes from the chemicals, irritation or injury to various
organs, including the lungs, could result.
After Moore and Graves obtained cleanup instructions, they put
the leaking drums into larger salvage drums. Moore and another
Consolidated employee then proceeded to place absorbent material on
the spilled chemicals, sweep them up, and dispose of them. The men
were engaged in this cleanup for forty-five minutes to an hour.
After the cleanup, Moore returned to the Consolidated terminal. At
trial, he testified that about an hour after finishing the cleanup,
he began experiencing symptoms, including dizziness, watery eyes,
and difficulty in breathing. However, Moore was able to drop off
another Consolidated trailer as requested by his supervisor.
When he completed this delivery, Moore returned to
Consolidated's terminal and told his supervisor that he was sick.
The supervisor sent Moore to the company doctor. The next day,
Moore saw his family physician. After two to three weeks of
treatment by the family physician, Moore placed himself under the
care of a Dr. Simi, a pulmonary specialist. Dr. Simi released
Moore to return to work on the 11th day of June, 1990. After
working several days, Moore terminated his employment due to
LIVER, LUNGS, KIDNEYS, AND NERVOUS SYSTEM. DEGREE OF EFFECTS
DEPENDS ON CONCENTRATION AND LENGTH OF EXPOSURE.
. . .
COMMENTS: PROLONGED TOLUENE OVEREXPOSURE MAY INJURE
BLOOD, LIVER, LUNGS, KIDNEYS, AND NERVOUS SYSTEM AND MAY AGGRAVATE
EXISTING EYE, SKIN, AND RESPIRATORY DISORDERS.
3
difficulty breathing. On three occasions in the summer of 1990,
Moore also consulted Dr. Daniel E. Jenkins, a pulmonary specialist.
Dr. Jenkins diagnosed Moore's condition as reactive airways
dysfunction syndrome (“RADS”), an asthmatic-type condition. In
November of 1990, Moore consulted another pulmonary specialist, Dr.
B. Antonio Alvarez, who became his primary treating physician. Dr.
Alvarez confirmed Dr. Jenkins’s diagnosis and treated Moore for
RADS.
Moore reported to his physicians that he had smoked
approximately a pack of cigarettes a day for approximately twenty
years, and he continued to smoke at the time of trial. He also
reported that on April 23, 1990, when he was exposed to the Dow
chemical, he had just returned to work following a bout with
pneumonia. Moore also related a history of childhood asthma to his
treating physician.
Moore and his wife filed suit against Ashland Chemical, Inc.,
Ashland Oil, Inc., and others, primarily on grounds that Ashland
was negligent in insisting that Moore expose himself to vapors
created by the chemical spill. More specifically, Moore complained
that Ashland’s employee, Bart Graves, should have permitted Moore
to return to Consolidated's terminal where other employees could
have cleaned up the spill. He also complained that Graves did not
permit him to use a respirator during the cleanup. Ashland removed
the suit to federal court on the basis of diversity jurisdiction.
After extensive discovery and motion practice dealing
particularly with whether Moore's expert physicians, Dr. Jenkins
4
and Dr. Alvarez, would be permitted to testify, the case proceeded
to trial before a jury. At the conclusion of the trial, the jury
answered the following interrogatory in the negative: "Do you find,
from a preponderance of the evidence, that the negligence, if any,
of the person named below proximately caused the injury in
question: . . . (b) Ashland Chemical, Inc. and/or Ashland Oil,
Inc.” Thereafter, the district court entered a take nothing
judgment against Moore. On appeal, a divided panel of this Court
concluded that the district court had erred in refusing to allow
Dr. Jenkins, one of Moore's experts, to give an opinion on the
cause of Moore's illness, and reversed the district court's
judgment and remanded the case for a new trial. Moore v. Ashland
Chem., Inc., 126 F.3d 679 (5th Cir. 1997). We granted rehearing to
consider this case en banc and to clarify the standards district
courts should apply in determining whether to admit expert
testimony.
II.
In this appeal we focus on the trial court's refusal to permit
one of Moore's medical witnesses, Dr. Daniel E. Jenkins, to give an
opinion on the cause of Moore's illness. Some factual and
procedural background is necessary to understand the arguments of
the parties.
Moore sought to call two medical witnesses, Dr. Jenkins and
Dr. Antonio Alvarez. Dr. Jenkins, a well-qualified medical
specialist, was certified by the American Board of Internal
Medicine in 1947. He also had special training and taught in the
5
fields of pulmonary disease, allergy, and environmental medicine.2
Dr. Jenkins saw Moore on three occasions. He examined Moore,
performed a series of tests, and reviewed Moore's medical records.
He concluded that Moore was suffering from RADS. Based upon his
examination and tests, Dr. Jenkins expressed the opinion that
Moore's RADS had been caused by Moore’s exposure to vapors from the
chemical spill at Ashland’s facility in April of 1990. We will
discuss later in more detail the reasons Dr. Jenkins assigned for
his opinion. Generally, he relied upon the MSDS, which warned that
exposure to the Toluene solution could be harmful to the lungs, his
examination and test results, and the close, temporal connection
between Moore's exposure to the Toluene solution and the onset of
symptoms.
Dr. Alvarez, who was a former student of Dr. Jenkins, agreed
with Dr. Jenkins about the cause of Moore's RADS. Dr. Alvarez was
Moore's primary treating physician. In addition to the reasons
relied on by Dr. Jenkins, Dr. Alvarez supported his theory of
causation with a report of a study on RADS co-authored by Dr.
Stuart Brooks that he found in a medical magazine.3 One case study
2
The Defendants agree that Dr. Jenkins's qualifications are
outstanding. He served residencies in internal medicine,
tuberculosis, and chest disease and allergy, and was certified by
the American Board of Internal Medicine in 1947. After serving as
Chief Resident in Medicine and Assistant Professor of Medicine and
Physician in Charge of the Tuberculosis and Chest Unit at the
University of Michigan Medical School from 1943 to 1947, he spent
forty-four years on the faculty at Baylor Medical School. In 1991,
he went into practice in Houston with a group of physicians
specializing in respiratory ailments.
3
Stuart M. Brooks, M.D. et al., Reactive Airways Dysfunction
Syndrome (RADS), 88 CHEST 376 (1985).
6
in the report involved a clerk who was exposed to a Toluene mixture
in a small, enclosed room for two and one-half hours. Dr. Jenkins
initially stated in his deposition that he knew of no reported
literature that supported his causation opinion. During his in
limine testimony outside the presence of the jury at trial, Dr.
Jenkins, for the first time, pointed to the Brooks study relied on
by Dr. Alvarez.
Dr. Jenkins admitted that Moore was his first RADS patient
with a history of exposure to Toluene. He had conducted no
research on this subject. Dr. Jenkins had previously treated other
patients whose RADS he attributed to exposure to chemicals that
were known to irritate the airways. However, he conceded that the
chemicals involved with these previous patients were stronger and
more irritating than the Toluene solution to which Moore was
exposed. Dr. Jenkins made no attempt to explain how any of the
other chemicals that he believed caused RADS in his earlier
patients had properties similar to the Dow Toluene solution.
The district court, after reviewing Dr. Jenkins’s deposition
and listening to his in limine testimony, decided to exclude his
causation opinion. The court did permit Dr. Jenkins to testify
about his examination of Moore, the tests he conducted, and the
diagnosis he reached. The only feature of Dr. Jenkins's testimony
the court excluded was his opinion that the Toluene solution caused
Moore's RADS. The district court concluded that Dr. Jenkins had no
scientific basis for this opinion, that it was not sufficiently
reliable under Fed. R. Evid. 702, and that it would be inconsistent
7
with the court's gatekeeper role under Daubert to admit this
opinion.
The district court decided to admit Dr. Alvarez's causation
opinion even though it was essentially identical to Dr. Jenkins's
proffered opinion. The district court was apparently convinced
that Dr. Alvarez's opinion linking the RADS to Moore's exposure to
the Toluene solution was more reliable than Dr. Jenkins's opinion
because Dr. Alvarez had been the treating physician, and also
because he had relied from the outset on the Brooks study and
therefore had some support from the scientific literature for his
conclusion. In view of the verdict, the Defendants do not
challenge the district court's decision to admit Dr. Alvarez's
opinion. Thus, the propriety of this ruling is not presented to us
for review.
The single defense expert, Dr. Robert Jones, was the third
medical witness to testify. Based upon his review of the medical
records, Dr. Jones concluded that Moore did not have RADS; rather,
according to Dr. Jones, Moore suffered from a form of bronchial
asthma. Dr. Jones further testified that the evidence in the case
was insufficient to allow him to conclude that Moore's exposure to
Toluene caused his pulmonary problems. Dr. Jones’s conclusion was
reinforced by Moore's medical history, which included conditions
that Dr. Jones thought were much more likely triggering agents for
RADS. These conditions included Moore's history as a heavy smoker
for approximately twenty years, his history of asthma, and his
recent bout with pneumonia. Dr. Jones also testified that the
8
scientific literature revealed that Toluene and similar substances
have a low potential for causing lung injury except when
encountered in such high dosages that the person is overcome and
passes out.
With this background, we now turn to the issue presented by
this appeal: whether the district court erred in excluding Dr.
Jenkins's causation testimony.
III.
A.
Fortunately, the Supreme Court recently resolved a
disagreement among the circuits about the standard for reviewing a
district court's admission or exclusion of expert testimony. In
General Electric Co. v. Joiner, 118 S. Ct. 512 (1997), the Court
held that we should review such decisions for an abuse of
discretion. In evaluating whether the district court abused its
discretion in excluding Dr. Jenkins's testimony on causation, the
Supreme Court's decisions in Daubert v. Merrell Dow
Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786 (1993), and
Joiner control our analysis.
In Daubert, the lower courts considered the admissibility of
expert testimony on medical causation. The expert witnesses sought
to testify that ingestion of Bendectin, a prescription anti-nausea
drug, by several mothers caused birth defects in their children.
The lower courts excluded the evidence on the basis that the
experts’ methodology was not generally accepted in the scientific
community and had not been subjected to peer review. The Supreme
9
Court, speaking through Justice Blackmun, first concluded that the
“Frye doctrine,”4 requiring that a theory be generally accepted in
the scientific community before it can be the basis of an expert's
opinion, was not a controlling principle in federal trials.
Daubert, 509 U.S. at 589, 113 S. Ct. at 2794. Justice Blackmun
then turned to Rule 702 of the Federal Rules of Evidence5 and the
proper test for admissibility of scientific evidence.
That the Frye test was displaced by the Rules of
Evidence does not mean, however, that the Rules
themselves place no limits on the admissibility of
purportedly scientific evidence. Nor is the trial judge
disabled from screening such evidence. To the contrary,
under the Rules the trial judge must ensure that any and
all scientific testimony or evidence admitted is not only
relevant, but reliable.
The primary locus of this obligation is Rule 702,
which clearly contemplates some degree of regulation of
the subjects and theories about which an expert may
testify. "If scientific, technical, or other specialized
knowledge will assist the trier of fact to understand the
evidence or to determine a fact in issue" an expert "may
testify thereto." The subject of an expert's testimony
must be "scientific . . . knowledge." The adjective
"scientific" implies a grounding in the methods and
procedures of science. Similarly, the word "knowledge"
connotes more than subjective belief or unsupported
speculation. The term "applies to any body of known
facts or to any body of ideas inferred from such facts or
accepted as truths on good grounds." Webster's Third New
International Dictionary 1252 (1986). Of course, it
would be unreasonable to conclude that the subject of
scientific testimony must be "known" to a certainty;
4
Frye v. United States, 293 F. 1013 (D.C. Cir. 1923).
5
Fed. R. Evid. 702 provides:
If scientific, technical, or other specialized
knowledge will assist the trier of fact to understand the
evidence or to determine a fact in issue, a witness
qualified as an expert by knowledge, skill, experience,
training, or education, may testify thereto in the form
of an opinion or otherwise.
10
arguably, there are no certainties in science. But, in
order to qualify as "scientific knowledge," an inference
or assertion must be derived by the scientific method.
Proposed testimony must be supported by appropriate
validation--i.e., "good grounds," based on what is known.
In short, the requirement that an expert's testimony
pertain to "scientific knowledge" establishes a standard
of evidentiary reliability.
Daubert, 509 U.S. at 589-90, 113 S. Ct. at 2794-95 (emphasis in
original) (internal citations omitted).
The Court stated further that:
Rule 702 further requires that the evidence or
testimony "assist the trier of fact to understand the
evidence or to determine a fact in issue." This
condition goes primarily to relevance. "Expert testimony
which does not relate to any issue in the case is not
relevant and, ergo, non-helpful."
Id. at 591, 113 S. Ct. at 2795 (citation omitted). The Court then
proceeded to enumerate a five-factor, non-exclusive, flexible test
for district courts to consider when assessing whether the
methodology is scientifically valid or reliable. These factors
include: (1) whether the expert's theory can be or has been tested;
(2) whether the theory has been subject to peer review and
publication; (3) the known or potential rate of error of a
technique or theory when applied; (4) the existence and maintenance
of standards and controls; and (5) the degree to which the
technique or theory has been generally accepted in the scientific
community. Id. at 593-95, 113 S. Ct. at 2796-97.6
6
The panel majority took the position that because Dr.
Jenkins's causation opinion was not predicated on "hard science,"
it was therefore not subject to Daubert's standards for
admissibility. We disagree. Daubert and Joiner both involved
questions of medical causation. As one of the scientists who filed
an amicus brief, Professor Alvan R. Feinstein, stated: "In other
words, determining the etiology of a disease--its cause--involves
11
The Supreme Court concluded by pointing out that important
differences exist between truthseeking in the courtroom and in the
laboratory:
Scientific conclusions are subject to perpetual revision.
Law, on the other hand, must resolve disputes finally and
quickly. The scientific project is advanced by broad and
wide-ranging consideration of a multitude of hypotheses,
for those that are incorrect will eventually be shown to
be so, and that in itself is an advance. Conjectures
that are probably wrong are of little use, however, in
the project of reaching a quick, final and binding legal
judgment--often of great consequence--about a particular
set of events in the past. We recognize that, in
practice, a gatekeeping role for the judge, no matter how
flexible, inevitably on occasion will prevent the jury
from learning of authentic insights and innovations.
Daubert, 509 U.S. at 597, 113 S. Ct. at 2798-99. The Court
remanded the case to permit the lower courts to evaluate their
rulings in light of the multi-factor, flexible test it had just
announced.
Procedurally, Daubert instructs us that the district court
must determine admissibility under Rule 702 by following the
directions provided in Rule 104(a).7 Rule 104(a) requires the
the same scientific exercise, whether the decision is made by a
clinician, an epidemiologist, or other scientist." Brief of Dr.
Feinstein,
Sterling Professor of Medicine and Epidemiology at the Yale
University School of Medicine and author and co-author of more than
375 peer-reviewed articles and five scientific texts, including
Clinical Judgment.
In any event, in this Circuit an opinion is governed by Fed.
R. Evid. 702 and Daubert, even though the opinion is not grounded
in "hard science,” assuming such a distinction exists. In Watkins
v. Telsmith, Inc., 121 F.3d 984 (5th Cir. 1997), we rejected the
position that application of the Daubert factors is unwarranted in
cases where expert testimony is based solely on experience or
training. Id. at 988-90.
7
Fed. R. Evid. 104(a) provides:
12
judge to conduct preliminary fact-finding and to make a
“preliminary assessment of whether the reasoning or methodology
underlying the testimony is scientifically valid and of whether
that reasoning or methodology properly can be applied to the facts
in issue.” Daubert, 509 U.S. at 592-93, 113 S. Ct. at 2796.
Thus, the party seeking to have the district court admit
expert testimony must demonstrate that the expert's findings and
conclusions are based on the scientific method, and, therefore, are
reliable. This requires some objective, independent validation of
the expert's methodology. The expert's assurances that he has
utilized generally accepted scientific methodology is insufficient.
See Daubert v. Merrell-Dow Pharmaceuticals, Inc., 43 F.3d 1311,
1316 (9th Cir. 1995) (on remand). The proponent need not prove to
the judge that the expert's testimony is correct, but she must
prove by a preponderance of the evidence that the testimony is
reliable. See In re Paoli R.R. Yard PCB Litigation, 35 F.3d 717
(3d Cir. 1994); see also 2 STEPHEN A. SALTZBURG ET AL., FEDERAL RULES OF
EVIDENCE MANUAL 1229-40 (7th ed. 1998).
In sum, the law cannot wait for future scientific
investigation and research. We must resolve cases in our courts on
the basis of scientific knowledge that is currently available. The
inquiry authorized by Rule 702 is a flexible one; however, a
scientific opinion, to have evidentiary relevance and reliability,
Preliminary questions concerning the qualification
of a person to be a witness, the existence of a
privilege, or the admissibility of evidence shall be determined by
the court, subject to the provisions of subdivision (b).
13
must be based on scientifically valid principles.
Last term, in General Electric Co. v. Joiner, 118 S. Ct. 512
(1997), the Supreme Court gave us helpful insight into the
application of the Daubert principles. In Joiner, the plaintiff
sued, claiming that his small-cell lung cancer was caused by his
exposure to polychlorinated biphenyls (“PCBs”) in the workplace.
The plaintiff offered expert testimony to establish his causation
theory. The district court ruled that the testimony was
scientifically unreliable and refused to admit the proffered
evidence. The Eleventh Circuit Court of Appeals reversed and held
that the simple abuse of discretion standard of review did not
apply to the ruling; rather, "a particularly stringent standard of
review” applied “to the trial judge’s exclusion of expert
testimony" that resulted in the dismissal of the suit. Joiner v.
General Elec. Co., 78 F.3d 524, 529 (11th Cir. 1996). The Supreme
Court reversed, holding that the usual abuse of discretion standard
generally applied to evidentiary rulings also applied to the
admission or exclusion of expert testimony. General Elec. Co. v.
Joiner, 118 S. Ct. 512 (1997). The Supreme Court's treatment of
several of Joiner's arguments is instructive to both trial courts
and courts of appeals in the area of admissibility of expert
testimony.
The Court emphasized that a district court, while acting as
a gatekeeper for expert evidence, must evaluate whether there is an
adequate "fit" between the data and the opinion proffered. Joiner,
118 S. Ct. at 519. One of the bases for the experts’ causation
14
opinion in Joiner was animal studies on the effects on rats
injected with large doses of PCBs. In analyzing Joiner's argument,
the Court observed that
[r]ather than explaining how and why the experts could
have extrapolated their opinions from these seemingly
far-removed animal studies, respondent chose to proceed
as if the only issue [was] whether animal studies can
ever be a proper foundation for an expert's opinion. Of
course, whether animal studies can ever be a proper
foundation for an expert's opinion was not the issue.
The issue was whether these experts' opinions were
sufficiently supported by the animal studies on which
they purported to rely. The studies were so dissimilar
to the facts presented in this litigation that it was not
an abuse of discretion for the District Court [sic] to
have rejected the experts’ reliance on them.
Id. at 518 (internal quotation and citation omitted).
The Court next considered four published epidemiological
studies on which the proffered experts relied to determine whether
they provided a sufficient basis for the experts’ opinion. The
Court observed that the authors of the first two studies, while
finding that the rate of cancer deaths among former employees at
plants where workers were exposed to PCBs was higher than might
have been expected, nevertheless concluded that "there were
apparently no grounds for associating lung cancer deaths (although
increased above expectations) and exposure in the plant." Joiner,
118 S. Ct. at 518 (citation omitted). The Court concluded that
given that the authors of the article were "unwilling to say that
PCB exposure had caused cancer among the workers they examined,
their study did not support the experts’ conclusion that Joiner's
15
exposure to PCBs caused his cancer." Id. at 518.8 The Court next
referred to the two remaining studies, one of which made no mention
of PCBs and the other in which the PCB-exposed group had also been
subjected to additional potential carcinogens. The Court observed
that the district court was entitled to conclude that these studies
were likewise no help to the experts in supporting their opinions.
Id. at 519.
The Court concluded its discussion of Joiner's arguments as
follows:
Respondent points to Daubert's language that the
"focus, of course, must be solely on principles and
methodology, not on the conclusions that they generate."
He claims that because the District Court's disagreement
was with the conclusion that the experts drew from the
studies, the District Court committed legal error and was
properly reversed by the Court of Appeals. But
conclusions and methodology are not entirely distinct
from one another. Trained experts commonly extrapolate
from existing data. But nothing in either Daubert or the
Federal Rules of Evidence requires a district court to
admit opinion evidence which is connected to existing
data only by the ipse dixit of the expert. A court may
conclude that there is simply too great an analytical gap
between the data and the opinion proffered. That is what
the District Court did here, and we hold that it did not
abuse its discretion in so doing.
Joiner, 118 S. Ct. at 519 (internal citations omitted).
B.
With this background, we turn to the record evidence in this
case to apply the Supreme Court’s directives in Daubert and Joiner,
and to determine whether the district court abused its discretion
8
This analysis by the Supreme Court is particularly relevant
to our case. The Brooks study relied upon by Dr. Jenkins suffered
from the same self-doubts as the studies in Joiner. Dr. Brooks was
unable to reach any conclusions based on his isolated studies.
16
in excluding Dr. Jenkins's testimony.
Dr. Jenkins pointed to the following support for his causation
conclusion: (1) the MSDS from Dow warned that exposure to fumes
from the Toluene solution could cause injury to the lungs; (2)
Moore had an onset of symptoms shortly after his exposure to the
Toluene solution; (3) although Dr. Jenkins did not initially rely
on the Brooks article, when it was called to his attention at trial
by counsel, he did claim to have knowledge of the article and
stated that he had relied on it; (4) his training and experience;
and (5) his examination and test results.
The district court was entitled to conclude that the above
bases for Dr. Jenkins's opinion were individually and collectively
inadequate under Daubert. First, Dr. Jenkins's training and
experience and his examination and tests, items 4 and 5 above,
were obviously important to his diagnosis. However, Dr. Jenkins
gave no reason why these items were helpful in reaching his
conclusion on causation. He admitted that he had never previously
treated a patient who had been exposed to a similar Toluene
solution. Dr. Jenkins was a highly qualified pulmonary specialist,
but, as the Seventh Circuit observed in Rosen v. Ciba-Geigy Corp.,
78 F.3d 316 (7th Cir. 1996), "[u]nder the regime of Daubert a
district judge asked to admit scientific evidence must determine
whether the evidence is genuinely scientific, as distinct from
being unscientific speculation offered by a genuine scientist."
Id. at 318 (internal citation omitted).
With respect to the Brooks article, item 3 above, the authors
17
made it clear that their conclusions were speculative because of
the limitations of the study. Also, in the single study involving
exposure to Toluene fumes, the level and duration of the exposure
was several times greater than Moore's exposure.
The bases for Dr. Jenkins's causation opinion are therefore
reduced to the following: (1) the Dow MSDS from which Dr. Jenkins
could have gleaned that the contents of the drum were irritating to
the lungs at some level of exposure; and (2) the relatively short
time between Moore's exposure to the chemicals and the onset of his
breathing difficulty.
The district court was entitled to find that the Dow MSDS had
limited value to Dr. Jenkins. First, Dr. Jenkins admitted that he
did not know what tests Dow had conducted in generating the MSDS.
Second, and perhaps more importantly, Dr. Jenkins had no
information on the level of exposure necessary for a person to
sustain the injuries about which the MSDS warned. The MSDS made it
clear that the effects of exposure to Toluene depended on the
concentration and length of exposure.
The district court was also correct in viewing with skepticism
Dr. Jenkins’s reliance on the temporal proximity between the
exposure and injury. Cavallo v. Star Enter., 892 F. Supp. 756
(E.D. Va. 1995), aff'd. in part, 100 F.3d 1150 (4th Cir. 1996),
contains a helpful discussion of this issue. In that case, the
plaintiff alleged that she suffered respiratory illness as a result
of exposure to aviation jet fuel vapors. The proffered expert
relied substantially on the temporal proximity between exposure and
18
symptoms. The court concluded that this reliance was "not
supported by appropriate validation" as required by Daubert, and
was “ultimately unreliable.” 892 F.Supp. at 773. The court
observed that although "there may be instances where the temporal
connection between exposure to a given chemical and subsequent
injury is so compelling as to dispense with the need for reliance
on standard methods of toxicology," this was not such a case. Id.
at 773-74. The court pointed out that the plaintiff in Cavallo was
not doused with jet fuel and that there was no mass exposure of jet
fuel to many people who in turn suffered similar symptoms. In the
absence of an established scientific connection between exposure
and illness, or compelling circumstances such as those discussed in
Cavallo, the temporal connection between exposure to chemicals and
an onset of symptoms, standing alone, is entitled to little weight
in determining causation.9
Dr. Jenkins offered no scientific support for his general
theory that exposure to Toluene solution at any level would cause
RADS. Because he had no accurate information on the level of
Moore's exposure to the fumes, Dr. Jenkins necessarily had no
support for the theory that the level of chemicals to which Moore
was exposed caused RADS.10 Dr. Jenkins made no attempt to explain
9
See also Porter v. Whitehall Labs., Inc., 9 F.3d 607 (7th
Cir. 1993); 2 STEPHEN A. SALTZBURG ET AL., FEDERAL RULES OF EVIDENCE MANUAL
1233-34 (7th ed. 1998).
10
Given the paucity of facts Dr. Jenkins had available about
the level of Moore's exposure to the Toluene solution, his
causation opinion would have been suspect even if he had scientific
support for the position that the Toluene solution could cause RADS
in a worker exposed to some minor level of the solution. Under
19
his conclusion by asserting that the Toluene solution had
properties similar to another chemical exposure to which RADS had
been scientifically linked. Several post-Daubert cases have
cautioned about leaping from an accepted scientific premise to an
unsupported one. See Wheat v. Pfizer, Inc., 31 F.3d 340, 343 (5th
Cir. 1994); see also Braun v. Lorillard Inc., 84 F.3d 230, 235 (7th
Cir. 1996); Daubert, 43 F.3d at 1319; Cavallo, 892 F. Supp. at 769.
To support a conclusion based on such reasoning, the extrapolation
or leap from one chemical to another must be reasonable and
scientifically valid. See Daubert, 43 F.3d at 1319-20; Cavallo,
892 F. Supp. at 769.
In the end, Dr. Jenkins was relegated to his fall-back
position that any irritant to the lungs could cause RADS in a
susceptible patient. Dr. Jenkins cited no scientific support for
this theory. None of Daubert's factors to assess whether the
opinion was based on sound scientific principles was met. Dr.
Jenkins's theory had not been tested; the theory had not been
subjected to peer review or publication; the potential rate of
error had not been determined or applied; and the theory had not
been generally accepted in the scientific community. In sum, Dr.
Jenkins could cite no scientific support for his conclusion that
exposure to any irritant at unknown levels triggers this asthmatic-
type condition. Under the Daubert regime, trial courts are
Daubert, "any step that renders the analysis unreliable . . .
renders the expert's testimony inadmissible. This is true whether
the step completely changes a reliable methodology or merely
misapplies that methodology." In re Paoli R.R. Yard PCB
Litigation, 35 F.3d 717, 745 (3d Cir. 1994) (emphasis in original).
20
encouraged to exclude such speculative testimony as lacking any
scientific validity.
The district court was also entitled to conclude that Moore's
personal habits and medical history made Dr. Jenkins's theory even
more unreliable. Moore had been a moderate to heavy smoker for
twenty years. In addition, he had just recovered from pneumonia
shortly before his contact with the chemicals. Finally, Moore had
suffered from asthma (a condition very similar to RADS) in his
youth.
In sum, the district court did not abuse its discretion in
finding that the “analytical gap” between Dr. Jenkins's causation
opinion and the scientific knowledge and available data advanced to
support that opinion was too wide. The district court was entitled
to conclude that Dr. Jenkins's causation opinion was not based on
scientific knowledge that would assist the trier of fact as
required by Rule 702 of the Federal Rules of Evidence.
CONCLUSION
Daubert and its progeny give the district court discretion to
"keep the gate" for the purpose of admitting or excluding opinion
testimony. In this case, the district court did not abuse that
discretion in concluding that the causation evidence proffered by
Dr. Jenkins should be excluded. It was within the judge’s
discretion to conclude that Dr. Jenkins’s testimony was not
grounded in science as required by Daubert and its progeny, and,
therefore, was not sufficiently reliable for the jury to consider.
We therefore affirm the judgment of the district court.
21
AFFIRMED.
KING, Circuit Judge, concurs in the result reached by the majority.
ENDRECORD
22
BENAVIDES, Circuit Judge, specially concurring:
Although I join both the reasoning and result of the
majority opinion, I write separately to reiterate that, under
General Electric Co. v. Joiner, ___ U.S. ___, 118 S. Ct. 512
(1997), the issue before us is whether the magistrate judge
abused her discretion in excluding the testimony of Dr. Jenkins.
While I believe this case to be a close one, I must agree that
the magistrate judge acted within her discretion in excluding Dr.
Jenkins’s proffered testimony. It does not follow from this,
however, that she would have abused her discretion by admitting
the proffered testimony. On the contrary, had she admitted the
testimony, I would likewise be of the opinion that she acted
within her discretion. I do not read the majority opinion to
require otherwise.
ENDRECORD
DENNIS, Circuit Judge, with whom PARKER and STEWART, Circuit
Judges, join, dissenting:
I respectfully dissent.
The majority en banc opinion (1) conflicts with the view of
other circuits, a state court of last resort, and scholarly
commentary, in holding that (a) a clinical medical expert cannot
express an opinion as to a causal relationship between a chemical
compound and a plaintiff’s disease, although the opinion is based
on the sound application of generally accepted clinical medical
methodology, unless the causal link is confirmed by hard
scientific methodology as per the Daubert factors11, see Daubert
v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 593-94
(1993); (b) the temporal relationship between chemical exposure
and symptoms of disease are to be accorded little weight by
courts in assessing an expert’s determination of causation with
either clinical medical or hard science methodology; (c) even
when an expert has hard scientific support for a general causal
relationship between a chemical compound and a particular
disease, his opinion of a specific causal relationship between
11
Evidently, the majority interprets the final Daubert factor,
“general acceptance,” to mean acceptance within a relevant “hard
scientific” community. For it is undisputed that the methods and
techniques used by Dr. Daniel Jenkins to determine that Mr. Moore’s
RADS had been caused by his exposure to the chemical compound, i.e.
history taking, physical examinations, differential etiology
(conducting tests to eliminate other diagnoses and causes of the
patient’s disease), and review of other physicians’ reports were
generally accepted within the doctor’s own clinical medical
disciplines of pulmonary and environmental medicine.
24
the compound and an individual’s disease is “suspect” unless the
expert also has scientifically accurate data as to the level of
that person’s exposure to the chemical compound; (2) conflicts
with Supreme Court decisions by conducting a de novo trial of the
preliminary assessment hearing on the record, substituting its
own erroneous ruling and reasons for those of the district court,
and disregards the district court’s errors of law, clearly
erroneous factual findings, and abuse of discretion.
1.
After Daubert, federal courts have become balkanized on
important questions that confront federal trial judges daily,
e.g., whether Daubert applies outside the field of hard science;
if so, whether Daubert’s gatekeeping function applies to the
admission of any or all of the other types of expert testimony;
if so, whether application of the Daubert “factors” is required
in the admission of any or all testimony based on knowledge not
derived by hard scientific methodology. Even before the present
en banc circuit opinion there was a clear and present need for
the Supreme Court to clarify whether and, if so, how, Daubert
applies to expert testimony based on knowledge derived by
disciplines or sources other than the hard sciences. E.g., 29
Charles A. Wright and Victor J. Gold, FEDERAL PRACTICE AND PROCEDURE
§6266 (1997); 2 Michael H. Graham, HANDBOOK OF FEDERAL EVIDENCE
§702.5, pp.22-26 (Supp. 1998).
25
(a)
The majority opinion represents an eccentric additional
fragmentation of the Daubert picture that underscores the need
for Supreme Court guidance. This circuit now takes the position
that a clinical medical expert, correctly using and applying
generally accepted clinical medical methodology, may not express
an opinion as to whether a particular chemical compound caused,
aggravated, or contributed to a person’s disease or disorder
unless that opinion is corroborated by hard scientific
methodology that passes muster under a rigid application of the
Daubert factors.
The majority’s rule applies even to single plaintiff
negligence actions that do not involve substances alleged to
cause diseases in large numbers of persons or diseases having
long latency periods. The en banc majority opinion emanates from
a case in which a single plaintiff claims to have developed a
reactive airways disorder as a result of a defendant’s negligence
in causing him to clean up a spillage of a chemical compound
without taking any safety precautions. The defendant refused to
provide the plaintiff with a respirator or to measure the air
contamination with a safety meter although the defendant had both
devices ready at hand. The plaintiff was required to work in and
around an enclosed 28-foot trailer for about an hour in cleaning
up the spilled chemical compound.
Unlike many toxic torts situations, in Mr. Moore’s case
there was not a long latency period between the onset of symptoms
26
and the chemical compound gases that were alleged to have caused
his illness. The onset of the plaintiff’s respiratory disease
occurred less than an hour after his exposure during his clean up
of the chemical compound. He immediately sought emergency
medical treatment, which included being given oxygen, and he has
been under treatment for his respiratory disease ever since.
The particular circumstances of the plaintiff’s inhalation
injury, combined with the fact that so few humans have ever been
subjected to a similar exposure to the chemical compound
involved, obviously impacted on the manner in which the plaintiff
could prove causation. The quantity of persons who sustain this
type of exposure was simply too small for a plaintiff to be able
to provide epidemiological, animal testing or other hard
scientific evidence linking the particular chemical compound to
reactive airways disease. See Zuchowicz v. United States, 140
F.3d 381, 385-86 (2nd Cir. 1998)(described infra.).
Although the en banc majority recognizes that cases
involving chemical compounds which have not been subjected to
hard scientific testing must be timely resolved and cannot await
the fortuity of relevant scientific experimentation, the majority
nevertheless insists that every admissible medical causation
opinion in a chemical injury case must have a hard science,
Daubert factor related basis. If such hard scientific data is
not available, the majority decrees, a plaintiff must face trial
or the defendant’s summary judgment motion without a medical
27
causation expert witness.12
12
In Daubert, the Court stated:
Scientific conclusions are subject to
perpetual revision. Law, on the other hand,
must resolve disputes finally and quickly.
The scientific project is advanced by broad
and wide-ranging consideration of a multitude
of hypotheses, for those that are correct will
eventually be shown to be so, and that in
itself is an advance. Conjectures that are
probably wrong are of little use, however, in
the project of reaching a quick, final and
binding legal judgment--often of great
consequence--about a particular set of events
in the past. We recognize that, in practice,
a gatekeeping role for the judge, no matter
how flexible, inevitably on occasion will
prevent the jury from learning of authentic
insights and innovations. Daubert, 509 U.S.
at 597.
The majority en banc opinion quotes this passage at page 12
and proceeds to stand it on its head on page 13, interpreting the
Supreme Court’s words as supporting the majority’s proposition that
although hard scientific proof of medical causation will not always
be available in chemical injury cases, the cases must be quickly
resolved; therefore, in chemical injury cases, if the plaintiff can
produce only clinical medical experts whose opinions are based
solely on well accepted clinical medicine methodology, they must
face trial without a medical causation expert witness.
The Daubert Court neither expressed nor implied such a
draconian rule. Being confronted with a case involving the
admissibility of hard science epidemiological expert opinions, not
generally accepted in that field, proffered to prove that Bendectin
could have caused birth defects in children whose mothers used the
drug, the Court concluded that the evidence could not be excluded
under the Frye rule which was superseded by the Federal Rules of
Evidence, but that the trial judge as gatekeeper must determine
that the hard science evidence proffered is not only relevant but
also reliable as based on a sound application of the methodology of
the expert’s discipline and suggested several ways, based on basic
elements of hard science methodology, that a party who proffers an
expert who proposes to testify to a hard scientific opinion can
show that the opinion is reliable or, reciprocally, that a court
can use to test the opinion’s reliability.
These ways of testing or showing reliability of hard
scientific opinions have become known as the “Daubert factors.”
But the Court did not intend to require that these gauges of
reliability be applied monolithically to all expert testimony.
28
The majority opinion creates a schism between this court and
other circuits and a state court of last resort and disregards
the teachings of federal evidence law scholars.
The Second, Fourth, and Third Circuits have held that a
clinical physician may, consistently with Daubert, express an
opinion, based on clinical medical methodology generally accepted
within that discipline, that a particular toxic substance caused
the patient’s disease or death, without hard scientific
corroboration under an inflexible application of the Daubert
factors.
The Second Circuit in McCullock v. H.B. Fuller Co., 61 F.3d
1038 (2nd Cir. 1995), rejected the defendant’s argument for
exclusion of a clinical physician’s opinion, as scientifically
unfounded, that glue fumes caused the plaintiff’s respiratory
symptoms and throat polyps. The doctor’s opinion was based
When the expert does not propose to testify to an opinion based on
hard scientific methodology, the Court indicated that the
reliability of his opinion should be assessed according to the
methodology of the expert’s own discipline. The Daubert court did
not indicate, and this court is not called upon to decide, what a
trial court should do if it is confronted by proffers of experts
who propose to testify to directly conflicting opinions as to
medical causation, one based on hard scientific methodology and the
other based on clinical medical methodology. In such a case, it is
likely that the trial court should find the clinical medical
expert’s opinion unreliable if it fails to take into account and
distinguish the hard scientific expert’s opinion and its basis in
hard scientific data, if the court finds the latter to be reliable.
The Daubert Court did no suggest, however, that the Federal Rules
of Evidence authorize a federal court to formulate a rule, as the
en banc majority has done, that, in effect, bars a clinical
physician from expressing an opinion as to the probable chemical
causation of a disease in a specific individual until the existence
of a general causal relationship has been confirmed by the use of
hard scientific methodology.
29
entirely upon his use of clinical medical methodology, without
any hard science or strict Daubert factor related basis. The
doctor could not point to a single piece of medical literature
that said that glue fumes cause throat polyps. In describing the
doctor’s use of clinical medical methodology as vouching for the
reliability of his opinion, the court stated:
[Dr.] Fagelson based his opinion on a range of factors,
including his care and treatment of McCullock; her
medical history (as she related it to him and as
derived from a review of her medical and surgical
reports); pathological studies; review of Fuller’s
MSDS; his training and experience; use of a scientific
analysis known as differential etiology (which requires
listing possible causes, then eliminating all causes
but one); and reference to various scientific and
medical treatises. Disputes as to the strength of his
credentials, faults in his use of differential etiology
as a methodology, or lack of textual authority for his
opinion, go to the weight, not the admissibility, of
his testimony. Id. at 1044.
In Zuchowicz v. United States, 140 F.3d 381 (2nd Cir. 1998),
the Second Circuit reaffirmed its holding in McCullock. The
Zuchowicz court approved the admission of a pulmonary medical
expert’s opinion that a negligent overdose of Danocrine had been
responsible for the pulmonary disease related death of the
plaintiff’s wife. The doctor based his opinion on the temporal
relationship between the overdose and the start of the disease,
the deceased’s apparent good health prior to the overdose, and
the differential etiology method of excluding other possible
30
causes. Id. at 385. He also testified that Mrs. Zuchowicz’s
illness was similar in onset, timing and course of development to
other cases of pulmonary diseases known to have been caused by
other classes of drugs. Id. at 385-86. There had been no
scientific tests to determine the effects of dosages at the level
received by Mrs. Zuchowicz, and the doctor’s opinion as to
medical causation, based solely on clinical medical methodology,
was not confirmed by any hard science or strict Daubert factor
evidence. See also Ambrosini v. Labarraque, 101 F.3d 129, 138
(D.C. Cir. 1996)(stating that the fact that a case may be the
first of its type should not prevent a plaintiff’s doctor from
testifying as to causation).
Similarly, the Fourth Circuit in Benedi v. McNeil-P.P.C.,
Inc., 66 F.3d 1378, 1384 (4th Cir. 1995), upheld the plaintiff’s
recovery for severe liver damage resulting from his use of Extra-
Strength Tylenol contemporaneously with alcohol due to the
manufacturer’s negligent failure to warn. The Court of Appeals
rejected McNeil’s argument that the medical causation testimony
of the plaintiff’s clinical physicians based on the methodology
of their discipline, such as the microscopic appearance of his
liver, the Tylenol found in his blood, the history of several
days of using Tylenol and alcohol, the liver enzyme blood level,
and the lack of evidence of a viral or other cause of liver
failure, was unreliable because they did not have or rely on
epidemiological data. The Benedi court stated: “We will not
declare [the clinical medicine] methodologies invalid and
31
unreliable in light of the medical community’s daily use of the
same methodologies in diagnosing patients.” Id.; see also,
Maryland Casualty Co. v. Therm-O-Disc, Inc., 137 F.3d 780, 785
(4th Cir. 1998)(“[T]his circuit has taken the position that the
Daubert court ‘was not formulating a rigid test or checklist,’
and was ‘relying instead on the ability of federal judges to
properly determine admissibility.’”)(citing and quoting Benedi,
66 F.3d at 1384)).
The Third Circuit in In Re Paoli R.R. Yard PCB Litigation,
35 F.3d 717 (3rd Cir. 1994) held that a clinical physician’s
methodology of differential diagnosis was sufficiently reliable
to support the admissibility of that expert’s opinion that
polychlorinated biphenyls (PCBs) caused specific plaintiffs’
illnesses. The Paoli court, heeding Daubert’s admonition that
the inquiry as to whether a particular technique or method is
reliable is a flexible one, id. at 742, reasoned that
“differential diagnosis can be considered to involve the testing
of a falsifiable hypothesis (e.g. that PCBs caused a plaintiff’s
cancer) through an attempt to rule out alternative causes,” and
although it “involves assessing causation with respect to a
particular individual[,][t]his merely makes it a different type
of science than science designed to produce general theories; it
does not make it unreliable science.” Id. at 758. Moreover, the
Paoli court concluded that a clinical physician’s performance of
standard diagnostic techniques provides prima facie evidence that
a doctor has considered alternative causes and has attempted to
32
test his or her initial hypothesis as to cause. Id.
The Court of Criminal Appeals of Texas, a state court of
last resort, in Nenno v. State, 1998 WL 331283 (Tex. Crim. App.
June 24, 1998)(“This opinion has not been released for
publication in the permanent law reports. Until released, it is
subject to revision or withdrawal.”), in reviewing the
defendant’s capital murder conviction and death sentence, held
that the trial court did not err in finding reliable and
admitting the state’s future dangerousness expert’s opinion that
the defendant would be a threat to society. The expert, an FBI
agent who specialized in studying the sexual victimization of
children, based his opinion on his study of over 1,000 cases,
personal interviews with inmates convicted of child sex offenses,
examination of inmates’ psychological records, and study of the
facts of the offenses involved. The Nenno court rejected the
defendant’s argument that the expert’s opinion was not reliable
because it did not rely on criteria substantially identical to
the Daubert factors. Instead, the Nenno court concluded that
“the four factors listed in Daubert do not necessarily apply
outside of the hard science context; instead methods of proving
reliability will vary, depending upon the field of expertise.”
Id. at *11 (citing the panel opinion in the present case, Moore
v. Ashland Chemical, Inc., 126 F.3d 679, 685-689 (5th Cir.
1997)).
Although the Nenno decision did not involve the testimony of
a clinical physician as to cause of disease in a specific person,
33
the court relied directly upon the Moore panel decision and its
underlying principle that the reliability of an expert witness’s
opinion ordinarily should be judged by whether it is soundly
grounded in the methodology of the expert’s discipline. Thus,
Nenno, which permits experts to predict the future causation of
criminal harm by a specific person without the support of any
hard scientific, strict Daubert factor type methodology, is at
odds with the premise of the present en banc majority opinion.
In similar manner, additional federal circuit decisions
conflict in principle with the en banc majority opinion’s
insistence on an inflexible, unthinking application of the
Daubert factors to expert opinions based on knowledge and
methodology outside the realm of hard science. E.g., Tyus v.
Urban Search Management, 102 F.3d 256, 263 (7th Cir.
1997)(“Social science testimony, like other expert testimony . .
. must be tested to be sure that the person possesses genuine
expertise in a field and that her testimony adheres to the same
standards of intellectual rigor that are demanded in her
professional work.” (internal quotation marks and brackets
omitted); Hose v. Chicago Northwestern Transp. Co., 70 F.3d 968,
974 (8th Cir. 1995)(clinical physician’s opinion that patient’s
inhalation of manganese caused patient’s manganese encephalopathy
was reliable although based only on patient history, laboratory
studies of manganese levels in patient’s body and work clothes,
clinical examinations, a series of MRIs, and other doctors’
reports); United States v. Jones, 107 F.3d 1147 (6th Cir.
34
1997)(although Daubert’s gatekeeper function is applicable to all
expert testimony, the Daubert factors do not extend outside the
hard scientific orbit to handwriting experts); see also Tassin v.
Sears, Roebuck and Co., 946 F.Supp. 1241, 1247-48 (M.D. La.
1996)(holding that for an expert’s opinion to be considered
reliable he must use the methodology of experts in his particular
field).
The majority’s opinion requiring a rigid, mechanical
application of the Daubert factors beyond the ambit of the hard
sciences also conflicts with the views of leading scholars,
jurists and practitioners.13 For example, the report of the
13
In addition to the views expressed by commentators and
practitioners, Stephen A. Saltzburg, et al. 2 FEDERAL RULES OF EVIDENCE
MANUAL at 1250-1251 (7th ed. 1998) reports that:
The Advisory Committee on Evidence Rules has made a
determination that Rule 702 should be amended in light of
Daubert and its progeny. The Advisory Committee has
prepared a working draft for an amended 702, which, at
this writing, has yet to receive final approval from the
Committee. The working draft, which is adapted from a
proposal by Professor Michael Graham, reads as follows:
Testimony providing scientific, technical or
other specialized information, in the form of an opinion,
or otherwise, may be permitted if:
(1)the information is based upon adequate
underlying facts, data or opinions;
(2)the information is based upon a
methodology either (a) established to have gained
widespread acceptance in the particular field to which
the explanative theory belongs, or (b) shown to possess
indicia of trustworthiness;
(3)the methodology has been applied
reliably to the facts of the case;
(4) the witness is qualified as an expert
by knowledge, skill, experience, training or education to
provide such information; and
(5) the information will assist the trier
of fact to understand the evidence or to determine a fact
in issue.
While the language set forth above is still in
35
American College of Trial Lawyers on Standards and Procedures For
Determining the Admissibility of Expert Evidence After Daubert,
157 F.R.D. 571 (1994) recognizes that the basic Daubert
requirement that a trial judge determine whether a proffer of
expert testimony is reliable or valid applies to all forms of
expert testimony and that the particular expert at issue should
have her methodology, i.e. the validity of her opinion, judged by
the principles applicable to “that particular field.” Id. at
577. In regard to the specific Daubert factors which the
majority so rigidly applies, the American College of Trial
Lawyers’ report concludes that:
. . . Justice Blackmun’s “general observations” about
the factors that a federal judge ought to consider in
evaluating the soundness of scientific methodology, set
forth in part II-C of his opinion, are specifically
aimed at the evaluation of scientific testimony. Of
course, some of these factors may be highly relevant to
an evaluation of certain types of non-scientific expert
evidence. For example, whether the proffered
development, the Advisory Committee has agreed upon some
general substantive points. First, the gatekeeper
standards of Rule 702 must apply to all expert
testimony..... Second, the reliability standards must
apply not only to the theory or methodology used by the
expert, but also to the application of that theory or
methodology in the specific case.... Third, it does not
pay to get too detailed about the factors that a Trial
Judge should use in assessing reliability.... The risk
of leaving out important reliability factors is
especially great because experts in different fields will
necessarily use different methodologies, and it would be
very difficult to describe an all-inclusive list of
reliability factors that would cover the testimony of all
experts.
36
methodology can be and has been tested may very well be
pertinent to an examination of non-scientific but
“technical” expert evidence. Peer review and
publication may be an important factor with respect to
testimony involving social sciences. And the “general
acceptance” of a methodology within a particular
discipline will be crucial in many cases. The point is
that any one of Justice Blackman’s four factors may or
may not have applicability to proffers of non-
scientific expert evidence. The inquiry to be made
concerns the fundamental principles by which the
validity of a methodology is to be judged in the
particular field of knowledge. Id. (footnotes
omitted)(emphasis added)
Leading federal evidence commentators have noted that the
Daubert opinion is ambiguous and has given rise to a number of
interpretations. E.g. 29 Charles A. Wright and Victor J. Gold,
FEDERAL PRACTICE AND PROCEDURE §6266 (1997). They observe that at its
narrowest Daubert can be read to allow judges to exercise a
signifigant gatekeeping function only in the case of expert
testimony in the hard sciences based on novel theories and
methodologies. Id. at 289. They further state that the broadest
reading of Daubert is that it applies to all reliability issues
presented by all expert testimony. Id. at 290. In rejecting
the broadest view, Wright and Gold state:
This broadest interpretation of Daubert should be
rejected. As noted above, it is inconsistent with both
policy and precedent to make the admissibility of all
expert testimony depend upon a showing that the
37
expert’s testimony is completely reliable in every
respect. Since Daubert does not explicitly take such a
position, and nothing in the Evidence Rules compels it,
it seems unlikely that the Court intended such a
departure from past practice. In overturning Frye, it
is unlikely that the Court in Daubert sought to make
the admission of scientific evidence harder. Id. at
290-91 (footnotes omitted).
Professor Michael Graham contends that Daubert boxes the
courts into working within a structure that has not functioned as
anticipated by the Supreme Court and can fairly be said to not
have functioned well at all. 2 Michael H. Graham, HANDBOOK OF
FEDERAL EVIDENCE, §702.5, pp.22-26 (Supp. 1998). Graham strongly
advises against a rigid application of the Daubert factors and
suggests that:
Until the Daubert box is removed, on balance, it is
suggested that Daubert’s gatekeeping language should be
held by lower courts to apply to “scientific” evidence
only. This interpretation is most consistent with the
plain meaning of the opinion and the clear choice for
liberalization if liberal admissibility is in fact the
goal. Most importantly, nonapplication of judicial
gatekeeping to “technical or other specialized
knowledge” would prevent the hardship incurred by many
plaintiffs in product liability litigation. Such an
interpretation also avoids unthinking application of
the four Daubert factors as well as the alternative
trying process of developing a list of factors for
determining whether a construction worker with 30 years
of reinforced concrete experience is testifying to an
explanative theory that is sufficiently trustworthy.
38
Id. at 25-26.
In Daubert, the Supreme Court stated: “The inquiry
envisioned by Rule 702 is, we emphasize, a flexible one.”
Daubert, 509 U.S. at 594. The en banc majority opinion, however,
heedless of Daubert’s precept, and unmindful of the other
circuits’ unanimous adoption of a flexible approach in applying
the Daubert factors, holds that district courts in this circuit
must unthinkingly and rigidly apply the Daubert factors in
assessing the reliability of a clinical physician’s opinion as to
the causal relationship between an individual’s exposure to a
chemical or substance and that person’s disease or medical
disorder.14 This means, of course, that in cases such as the
14
The panel opinion in the present case, Moore v. Ashland
Chemical Co., Inc., 126 F.3d 679 (5th Cir. 1997), consistently with
the foregoing authorities, concluded that: (1) the basic principles
of the Federal Rules of Evidence recognized in Daubert apply to the
admission or exclusion of every type of expert testimony; (2) a
trial judge, therefore, must assess every proffer of expert
testimony to determine whether it is relevant to the case and a
reliable application of the principles and methodology of that
expert’s discipline; (3) the Supreme Court in Daubert interpreted
“scientific knowledge” under Federal Rule of Evidence 702, for
purposes of that case, to mean knowledge obtained and tested by the
scientific method, i.e., “hard” scientific knowledge; (4)
accordingly, the Daubert court indicated that a trial court should
assess the reliability of expert testimony professedly based on
“hard” scientific knowledge using several factors, the ”Daubert
factors,” which are “hard” science methods or techniques; (5)
clinical medicine (as opposed to research and laboratory medical
science) is not, strictly speaking, a “hard” scientific discipline;
its goals, subject matter, conditions of study, and well developed,
sui generis methodology are quite different from that of purely
“hard” science and its methodology; (6) Consequently, a trial judge
assessing the reliability of the proffer of a clinical physician’s
expert testimony based on clinical medical knowledge, without
purporting to be based on hard scientific methodology, should
determine whether it is a sound application of the knowledge,
principles and methodology of clinical medicine; (7) In the present
39
present one, in which the association between a specific chemical
compound and a particular disease has not yet been, and perhaps
never will be, subjected to hard science investigation, that the
plaintiff will be unable to present any expert testimony that his
or her exposure to the chemical compound was the probable medical
cause of his or her disease.
The en banc majority adopts a mechanistic interpretation of
the Daubert factors that threatens to require the exclusion from
evidence of vast numbers of clinical medical opinions, although
they are generally accepted as trustworthy by physicians
practicing in their fields, and, until the majority’s decision
today, were routinely accepted as reliable by our courts both
before and after Daubert. See Carroll v. Morgan, 17 F.3d 787,
789-90 (5th Cir. 1994). Disturbingly, the majority does not
explain the reasons for its deviation from the other circuits or
its departure from the prior precedent and practice in our
courts. Ironically, the majority’s divergence occurs in a rather
run-of-the-mill setting, a case involving a clinical physician’s
opinion, based on generally accepted clinical methodology, as to
the cause of a non-catastrophic disease following a person’s
episodic and traumatic occupational exposure to a chemical
compound. Unlike Daubert, and other highly publicized toxic
torts cases, the present case does not involve “junk science,” or
case, the district court committed an error of law by rigidly
applying the “Daubert factors” and excluding the expert clinical
physician’s opinion because the doctor did not have any “hard”
scientific data to support his clinical medical opinion.
40
purportedly hard scientific opinions, based on epidemiological
and animal studies not generally accepted in their discipline, as
to the surreptitious causal relationship between drugs or other
substances and catastrophic systemic diseases or disorders such
as cancer and birth defects.
(b)
Having depleted the ranks of medical causation experts
available to plaintiffs suffering non-catastrophic chemical
exposure injuries, the majority adds insult to injury by casting
doubt on the importance of a principal element used by both hard
scientific and clinical medical experts in determining whether
there is a causal relationship between an individual’s exposure
to a substance and his or her disease viz., the temporal
relationship between the person’s exposure and the development of
symptoms or signs of disease. The majority asserts that in the
absence of an established scientific connection between exposure
and illness or compelling circumstances, the temporal connection
between exposure to chemicals and an onset of symptoms is
entitled to little weight in determining causation. Maj. Op. at
p. 19. This dictum conflicts with the great weight of
scientific and judicial authority.
In the sphere of hard science, the opinion of an expert who
opines that exposure to a compound caused a person’s disease is
“based on an assessment of the individual’s exposure, including
the amount, the temporal relationship between the exposure and
41
disease, and exposure to other disease-causing factors.” Federal
Judicial Center, REFERENCE MANUAL ON SCIENTIFIC EVIDENCE, p. 205
(1994)(emphasis added). The temporal relationship may either
support or contradict causation. “In most acute injuries, there
is a short time period between cause and effect. However, in
some situations, the length of basic biological processes
necessitates a longer period of time between initial exposure and
the onset of observable disease.” Id. at 207. Moreover,
temporal relationship is one of the seven factors that an
epidemiologist considers in determining whether the association
between an agent and a disease is causal. Id. at 161.
Courts and commentators have also recognized that the fact
that an individual’s symptoms followed an appropriate time after
exposure is an important consideration in determining causation.
E.g., Kannankeril v. Terminix Int’l., Inc., 128 F.3d 802, 805,
809 (3rd Cir. 1997); Zuchowicz, 140 F.3d at 385 (affirming the
admissibility of an expert whose “conclusion was based on the
temporal relationship between the overdose and the start of
disease and the differential etiology method of excluding other
possible causes.”); 1 Margie Searcy-Alford, A GUIDE TO TOXIC TORTS
§10.03[2], p.10-69 (1998)(“The fact that the symptoms follow an
appropriate time after exposure does not prove causation, but it
is an important consideration.”); Stephen A. Saltzburg et al.,
FEDERAL RULES OF EVIDENCE MANUAL at 1233-1234 (7th ed. 1998); see
Benedi v. McNeil-P.P.C., Inc., 66 F.3d 1378, 1384 (4th Cir.
1995); 3 Stuart M. Speiser et al., THE AMERICAN LAW OF TORTS §11.27,
42
at 465 (1986).
The district court case relied on by the majority, Cavallo
v. Star Enter., 892 F.Supp. 756 (E.D. Va. 1995), is
distinguishable in numerous respects and does not support the
majority’s assertion that temporal relationship is entitled to
“little weight” in the absence of compelling circumstances. In
Cavallo, the plaintiff’s exposure occurred in the open parking
lot of a shopping mall during a five minute period at a distance
of 500 feet from the source of the jet fuel fumes, the chemical
substance at issue; she did not seek medical assistance until
nine days later for her symptoms that resulted in an initial
diagnosis of “conjunctivitis, or eye redness;” her experts did
not have even a rough idea of the amount of her exposure; and
there was no showing that the fumes the plaintiff inhaled from
the defendant’s alleged negligent spillage were actually more
dense than the ordinary daily atmosphere in the shopping mall
near defendant’s petroleum distribution, mixing and transfer
terminal. Significantly, Cavallo’s experts did not have a
material safety data sheet (MSDS) or full knowledge of some of
the chemicals inhaled and, more importantly, they did not
reliably use or apply the methodology of their own disciplines.
In sum, the Cavallo court ruled the experts’ opinions
inadmissible because their opinions were based almost exclusively
on a very tenuous temporal and spatial connection between
exposure and symptoms and because they significantly departed
from the accepted toxicology methodology, while the defendant’s
43
toxicology expert followed the generally accepted methodology of
that discipline. Id. at 763, 773. Moreover, the Cavallo court
never said that, in the absence of compelling circumstances, a
temporal relationship is “entitled to little weight.” Instead,
that court merely observed that there may be instances where the
temporal connection is so compelling as to dispense with the need
for toxicologists to rely on the standard methodology of their
discipline. Id. at 773.
(c)
As a coup de grace to inhalation injury claimants, the
majority indicates that, if a plaintiff’s expert does not have
scientifically accurate measurements of the level of the
plaintiff’s exposure, “his causation opinion [will be] suspect
even if he ha[s] scientific support for the position that the
[chemical compound] could cause [the plaintiff’s disease].”
Maj. Op. p.19 n.9. The majority downplays the lethal swath of
its new rule by suggesting that it applies here because of “the
paucity of the facts Dr. Jenkins had available about the level of
Mr. Moore’s exposure.” But the truth is that Dr. Jenkins had
better information about the nature of the substances, the level
of exposure, and its duration than experts in most inhalation
accident cases.15 “Only rarely are humans exposed to chemicals
15
As explained by the panel opinion:
From Moore’s history that Dr. Jenkins had taken, he
had information that before the exposure Moore was in
good health, that two 400 pound drums of the chemicals
had begun leaking in the back of Moore’s truck at some
44
in a manner that permits a quantitative determination of adverse
outcomes. [] Human exposure occurs most frequently in
occupational settings where workers are exposed to industrial
chemicals like lead or asbestos; however, even under these
circumstances, it is usually difficult, if not impossible, to
quantify the amount of exposure.” Federal Judicial Center,
REFERENCE MANUAL ON SCIENTIFIC EVIDENCE, p. 187 (1994). Consequently,
the majority’s rule will apply in virtually all inhalation cases
to exclude the opinions of plaintiffs’ experts as to specific
medical causation even if they are fortunate enough to have hard
science data supporting a general causal relationship or
association between the chemical compound and the disease
involved. The majority does not have even a paucity of authority
to support this extra, gratuitous ratcheting down of inhalation
time before his arrival at Ashland, that Moore’s rig
consisted of a diesel tractor and a 28 foot enclosed
trailer, that after the discovery of the leakage upon
arrival at Ashland the drums were allowed to continue to
leak inside the trailer with the doors shut for another
45 minutes until the Ashland supervisor told Moore to
remove them, that at this point the 400 pound drums had
become light enough to allow Moore and others to roll
them manually out onto the dock, that Moore and a co-
employee worked in and around the trailer for about 45 to
60 minutes sprinkling “Absorbo” over the contaminated
areas sweeping the saturated material into shovels,
removing the materials from the trailer, and shoving the
leaking drums into salvage drums, that Moore finished the
cleanup at Ashland about 11:00 a.m., that Moore began to
experience tightness of chest at about 11:45 a.m., that
as his symptoms were continuing to worsen Moore consulted
the company doctor who put him on oxygen and inhalants.”
Moore, 126 F.3d at 702.
From this information, Dr. Jenkins was able to roughly
estimate that Mr. Moore had been exposed to possibly “200 parts per
million or higher” of the chemical compound. Id. at 695.
45
accident victims’ chances of recovery.
2.
The majority has conducted a trial de novo of the district
court’s preliminary assessment of whether the reasoning and
methodology underlying Dr. Jenkins’ testimony was reliable,
substituting its own erroneous judgment and reasoning for that of
the trial judge, rather than reviewing the district court’s
rulings and reasoning for abuse of discretion, General Electric
Co. v. Joiner, 118 S.Ct. 512, 517 (1997), clearly erroneous
factual findings, Bourjaily v. United States, 483 U.S. 171, 181
(1987), and errors of law, Koon v. United States, 518 U.S. 81,
100 (1996)(“A district court by definition abuses its discretion
when it makes an error of law”).
In the district court proceedings, the defendants objected
to the introduction of Dr. Jenkins’ opinion as to the diagnosis
and cause of Mr. Moore’s disease on the grounds that the doctor
lacked hard scientific support that the chemical compound
involved could cause reactive airways disease. The district
court admitted Dr. Jenkins’ opinion that Mr. Moore had reactive
airways disease but excluded Dr. Jenkins’ opinion that the
disease had been specifically caused by exposure to the chemical
compound involved because Dr. Jenkins had not presented any hard
scientific support for a general causal link or association
46
between that particular compound and that particular disease.16
The majority opinion retries the preliminary assessment of
Dr. Jenkins’ proffer de novo and concludes that (1) the district
court was “entitled to conclude” that (a) Dr. Jenkins had not
explained in sufficient detail how his differential diagnosis or
etiology and his training and experience were helpful in reaching
his conclusion on causation; (b) the MSDS had limited value in
supporting Dr. Jenkins’ opinion because he did not know what
tests Dow had conducted in preparing the MSDS or what level of
exposure was necessary for a person to sustain the injuries
warned of in the MSDS; (c) Mr. Moore’s asthma in his youth,
history of smoking and recovery from pneumonia shortly before his
exposure made Dr. Jenkins’ opinion even more unreliable; and (d)
the “analytical gap” between Dr. Jenkins’s causation opinion and
the scientific knowledge and available data advanced to support
that opinion was too wide; and (2) Dr. Jenkins did not explain
precisely how the irritating properties in the compound described
by the MSDS were similar to those in other chemicals or compounds
16
Dr. Jenkins performed a physical examination, took a detailed
medical history, observed Moore on three occasions, reviewed the
MSDS prepared by Dow Corning, and performed a series of tests on
Moore including pulmonary function tests, a bronchodilator test, a
spirometry test, a plethysmographic test, a lung volume
determination, an intrapial gas distribution test, a diffusion
test, an arterial bloods test, a mechanics test, X-rays, and
laboratory tests. Dr. Jenkins reviewed the medical records and
reports of a bronchodilator test performed by Dr. Simi two to three
weeks after the accident that showed severe airways obstruction.
Additionally, Dr. Jenkins reviewed a report of an allergy test
performed by Dr. Alvarez, which ruled out allergic or immunologic
disease and confirmed RADS. Finally, Dr. Jenkins also relied upon
the temporal proximity between the exposure to the chemicals at the
Ashland facility and the onset of symptoms.
47
that had been linked with reactive airways disease.
Dr. Jenkins testified that he did not know what tests Dow
had performed in preparing the MSDS warnings of the hazards of
the chemical compound. The district court commented on this fact
but based its ruling on the lack of hard scientific support for
the doctor’s clinical medical opinion, not on his lack of
knowledge of Dow’s testing. The MSDS was introduced without
objection and referred to in testimony by the experts on both
sides, none of whom professed to have any knowledge of Dow’s
MSDS-related testing. The record clearly demonstrates that Dr.
Jenkins used the MSDS only for the same purpose as did the other
experts, merely as a source of information as to the kinds of
chemicals in the compound to which Mr. Moore had been exposed.
Thus, the district court evidently gave no weight to the experts’
lack of knowledge of Dow’s testing, and if it did find any
relevance in this fact, it would have been clearly erroneous in
doing so. See Moore, 126 F.3d. at 701.
The district court, moreover, did not base its decision on
many of the findings and reasons that the majority now attributes
to it. Neither the defendant nor the district court found any
fault with Dr. Jenkins’ qualifications17, experience, testimony
17
The majority opinion fails to point out that Dr. Jenkins’
qualifications were never an issue at any point in these
proceedings. In fact, Dr. Jenkins was more than eminently
qualified to render an opinion in this matter as a brief summary of
his education, training and experience reveals. Dr. Jenkins
received his medical degree from the University of Texas in 1940,
received training at the University of Michigan Hospital as an
intern, resident in Tuberculosis and Chest Disease and resident in
Allergy in 1940-45, served as Instructor and Chief Resident in
48
regarding the similarity of irritating chemical properties, or
his proper performance of differential etiology to eliminate
alternative causes of Mr. Moore’s disease. Because the defendant
did not object to Dr. Jenkins’ opinion on these grounds or
question him on these points and the district court did not base
its ruling on them, these issues should not be raised sua sponte
by this court. The performance of physical examinations, taking
of medical histories, and employment of reliable laboratory tests
provide significant evidence of a reliable differential diagnosis
and prima facie evidence that a doctor has considered alternative
causes and has attempted to test his or her initial hypothesis as
to cause. See Paoli, 35 F.3d at 759. The failure of the
defendant or the district court to ask for, or the doctor’s
failure to volunteer, further elaboration on how each
differential diagnosis test is designed to eliminate each
alternative cause of disease or a chemistry professor’s exegesis
on the structure and composition of each chemical identified as
having similar irritating properties, does not afford a proper
basis for an appellate trial de novo on the record of the
district court’s preliminary assessment hearing.
Medicine and Assistant of Medicine and Physician in charge of the
Tuberculosis and Chest Unit, University of Michigan Medical School,
1943 to 1947, was certified by the American Board of Internal
Medicine in 1947, served in various capacities as a professor at
Baylor College of Medicine from 1947-91 where from 1947-74 he was
chief of the Pulmonary Disease Section and from 1975-91 chief of
environmental medicine. Additionally, in the course of over fifty
years of practicing medicine, Dr. Jenkins has examined and
evaluated over 100 persons for injuries occurring from exposure to
various chemical compounds in an occupational setting.
49
Likewise, the defendants did not contend, and the trial
judge did not rule, that Dr. Jenkins’ opinion was inadmissible
because of Mr. Moore’s childhood asthma, smoking or pneumonia.
Dr. Jenkins concluded that the exposure to the chemical compound
triggered Mr. Moore’s reactive airways disease after taking these
and all other relevant factors into consideration. The plaintiff
is not required to prove that the exposure was the exclusive
cause of the disease. It is well settled in Texas and elsewhere
that a defendant takes the plaintiff as he finds him. Coates v.
Whittington, 758 S.W.2d 749, 752 (Tex. 1988)(citing Driess v.
Friederick, 11 S.W. 493, 494 (Tex. 1889)); Mondragon v. Austin,
954 S.W.2d 191, 194 (Tex. Ct. App. 1997); see Maurer v. United
States, 668 F.2d 98, 99-100 (2nd Cir. 1981)(“It is a settled
principle of tort law that when a defendant’s wrongful act causes
injury, he is fully liable for the resulting damage even though
the injured plaintiff had a preexisting condition that made the
consequences of the wrongful act more severe than they would have
been for a normal victim. The defendant takes the plaintiff as
he finds him.”); W. Page Keeton, et al., PROSSER AND KEETON ON TORTS
§43 at 291-92 (5th ed. 1984).
The majority’s most blatant addition of its own ex post
facto finding and rationale in an effort to bolster the district
court’s ruling, however, is its erroneous claim that the district
court found “that the ‘analytical gap’ between Dr. Jenkins’s
causation opinion and the scientific knowledge and available data
advanced to support that opinion was too wide.” Maj. Op. p. 21.
50
The district court made no such finding. The term “analytical
gap,” comes from the Supreme Court’s Joiner opinion of 1997, see
118 S.Ct. at 519, and does not appear in the district court’s
1995 ruling in the present case.18 Moreover, as explained above,
18
In General Electric Co. v. Joiner, 118 S.Ct. 512 (1997), the
Supreme Court held that abuse of discretion, rather than the
particularly stringent standard of review applied by the court of
appeals in that case, is the proper standard by which to review a
district court’s decision to admit or exclude scientific evidence.
The plaintiff Joiner proffered expert testimony based on hard
science methodology, animal and epidemiological studies, to prove
that the defendants’ PCBs and related products had caused his lung
cancer. “Joiner’s experts used a ‘weight of the evidence’
methodology to assess whether Joiner’s exposure to transformer
fluids promoted his lung cancer. They did not suggest that any one
study provided adequate support for their conclusions, but instead
relied on all the studies taken together (along with their
interviews of Joiner and their review of his medical records).” Id.
at 521 (Stevens, J. concurring in part and dissenting in part)
(footnote omitted). The district court examined the studies and
excluded the experts’ opinions on the ground that none of the
studies was sufficient alone to show a link between PCBs and lung
cancer.
The Supreme Court held that the district court did not abuse
its discretion in excluding the experts’ testimony on grounds that
the studies upon which the experts relied were not sufficient,
whether individually or in combination, to support their
conclusions. The Supreme Court remarked that “[a] court may
conclude that there is simply too great an analytical gap between
the data and the opinion proffered.” Id. at 519.
In the present case, there was no “analytical gap” between Dr.
Jenkins’ data and his opinion that Mr. Moore’s exposure caused his
disease. In fact, the district court allowed Dr. Alvarez to use
the identical data to express the same opinion. It is easy to see
that the district court’s decision in Joiner was reasonable and not
an abuse of discretion because the plaintiff himself conceded that
there was an analytical gap between each one of his expert’s
studies and the conclusion that PCBs caused his cancer. He argued,
although unsuccessfully, however, that every analytical gap could
be bridged if all of the experts’ studies were considered in
combination. In the present case, the district court excluded Dr.
Jenkins’ opinion simply because he did not have any hard scientific
support for his clinical medical opinion, not because of a gap in
reasoning. Dr. Jenkins’ clinical medical opinion was, in fact,
snugly based on the sound application of the well accepted
methodology of his discipline. Thus, en banc the majority itself
is simply attempting to bridge too great an analytical gap by
51
the district court based its decision on the same erroneous
theory as the majority’s primary rationale, i.e., that a clinical
medical physician cannot express an admissible opinion,
regardless of how soundly he or she relies on and applies well
settled clinical medical methodology, unless the opinion is
further supported by hard science, rigid Daubert factor type
data.
Conclusion
In the final analysis, this case presents the legal question
of the proper interpretation of Federal Rule of Evidence 702 and
Daubert in cases involving expert witness proffers based on
knowledge beyond the realm of hard scientific knowledge. Indeed,
the majority en banc opinion is far too “rulefied” for anyone to
seriously contend that it does not set broad, eccentric
precedents that will profoundly affect the trials and outcomes in
substantial numbers of future cases involving injuries and
diseases alleged to have been caused by exposure to chemical
compounds. The en banc majority, in my opinion, makes several
errors of law, the most serious of which is its holding that a
clinical medical expert, whose opinion is based on a sound
application of the principles and methodology of his or her
discipline, cannot reliably testify as to the causal relationship
between and individual’s exposure to a chemical compound and his
trying to stretch Joiner to cover the present case.
52
or her subsequent onset of symptoms and disease. As a result of
this error of law and others, the en banc opinion subverts the
liberal thrust of the Federal Rules of Evidence and the
principles enunciated in Daubert by locking the gate on causation
evidence derived through the principles and methodology of
clinical medicine.
53