                           STATE OF MICHIGAN

                            COURT OF APPEALS



TERI WALTERS and KIM WALTERS,                                         UNPUBLISHED
                                                                      January 29, 2015
               Plaintiffs-Appellants,

v                                                                     No. 319016
                                                                      Eaton Circuit Court
DONALD S. FALIK, D.D.S., d/b/a FALIK                                  LC No. 12-000658-NH
FAMILY DENTISTRY, ROBERT C. FALIK,
D.D.S., and JANE DOE,

               Defendants-Appellees.


Before: MURPHY, P.J., and METER and SERVITTO, JJ.

PER CURIAM.

        Plaintiff Teri Walters (hereafter “Walters”) suffered an unintended exposure to
phosphoric acid contained in a dental etching solution supplied by defendants. Plaintiffs
proceeded to file a negligence action against defendants. The trial court granted summary
disposition in favor of plaintiffs on the question of liability, and liability is not at issue in this
appeal. Subsequently, the trial court granted defendants’ motion in limine, precluding the
testimony of plaintiffs’ proposed expert witness, Dr. M. Eric Gershwin, on the issue of causation
and damages. Plaintiffs claimed that the exposure to the phosphoric acid in the etching solution
triggered or caused Wegener’s granulomatosis (WG), an autoimmune disease that Walters was
diagnosed with after the exposure. As reflected in his deposition testimony, Dr. Gershwin was
prepared to testify in support of a causal connection between the exposure to phosphoric acid and
WG. The trial court, exercising its role as gatekeeper, concluded that Dr. Gershwin’s opinion on
causation was not supported by sufficient data and reliable scientific principles, MRE 702. We
reverse and remand for further proceedings.

        On October 20, 2010, Walters went to defendants’ dental office to have a permanent
crown seated, and following the procedure, she was provided with what she believed was a
whitening solution for her teeth. Instead, a receptionist mistakenly gave Walters an etching
solution, which was never intended to be dispensed to patients. An etching solution is used to
“etch” the surfaces of teeth in preparation for the application of dental restoratives, and it
contains phosphoric acid, which is a caustic acid and absolutely not meant to be used for teeth
whitening. Etching solution, when used properly, should only remain on a particular tooth for
about 20 seconds. A product safety data sheet regarding the etching solution indicated that it is
corrosive, can cause chemical burns to the skin, eyes, mouth, and throat, may cause permanent

                                                 -1-
tissue damage, is harmful if swallowed, can irritate the respiratory system, and may cause
swallowing difficulties, vomiting, diarrhea, and possible shock. Etching solution should not be
exposed to moist air or water. Walters refrigerated the etching solution for a few months without
using it, but on February 11, 2011, she spread the etching solution in her dental tray and left the
tray in her mouth overnight in an attempt to whiten her teeth. When she awoke, Walters had a
burning sensation inside of her mouth, including the sides of her tongue and along the gumline.

        Walters went to her doctor on February 24, 2011, and according to the associated medical
record, she complained of burns in her mouth as caused by the etching solution; she was
diagnosed as having a “chemical burn.” On April 5, 2011, Walters again visited her doctor,
complaining of sinus trouble that had been bothersome for a month, along with fullness in one
ear. The medical record documenting the visit indicated that the examination revealed raw and
swollen “[n]asal mucosa, septum, [and] turbinates.”1 Walters was diagnosed with sinusitis and
prescribed an antibiotic. She saw her doctor again on April 14, 2011, complaining of sinus
congestion and a very full feeling in her ears, which was at times painful. The medical record
documenting the visit indicated that Walters had been previously prescribed two different
antibiotics for the sinus problems, which were ineffective, that she was “[p]ositive for ear pain,
congestion, . . . and sinus pressure,” and that her examination revealed “[m]ucosal edema and
rhinorrhea.” Walters was diagnosed with acute sinusitis. On May 4, 2011, Walters saw an ear,
nose, and throat doctor (ENT) to be evaluated for chronic sinusitis. The associated ENT record
indicated that Walters reported a sinus infection that had been present for approximately 45 days,
continual plugging and fullness in her left ear, and ongoing sinus pain and pressure. The
physical examination revealed “dryness and crusting on the anterior septum on the left side” and
“fairly significant swelling in the ethmoid area bilaterally with drainage.” Following numerous
procedures and evaluations at a hospital, Walters was diagnosed in June 2011 with WG, which
has been explained and described as follows:

               [WG] is a primary vasculitis of the small blood vessels [inflammation of
       the blood vessels] in which a characteristic feature is production of antineutrophil
       cytoplasmic antibodies (ANCAs), usually targeted to proteinase 3 (PR 3). The
       symptoms, histology, and pathogenesis go through two phases. In the first phase,
       the disease is confined to the airways, causing sinusitis, otitis media, tracheal
       stenosis and/or pulmonary nodules. Histology usually shows granulomatous
       lesions. The second phase starts when the disease extends to other organs . . . .

              The pathogenesis of WG and other vasculitides associated with ANCAs
       remains unclear, but probably involves an interaction between a genetic
       susceptibility and environmental factors. [Hamidou, Audrain, Ninin, Robillard,




1
 A “turbinate” is “a small curved bone that extends horizontally along the lateral wall of the
nasal passage.” Webster’s New College Dictionary (2005).


                                                -2-
       Muller, and Bonneville, Staphylococcus aureus, T-cell repertoire, and Wegener’s
       granulomatosis, 68 Joint Bone Spine (June 2001), p 373.2]

        Before we examine Dr. Gershwin’s deposition testimony, we will review the medical and
scientific articles and literature relating to WG in order to provide context for Dr. Gershwin’s
testimony.

       In Mahr, Neogi, and Merkel, Epidemiology of Wegener’s granulomatosis: Lessons from
descriptive studies and analyses of genetic and environmental risk determinants, 24 Clinical and
Experimental Rheumatology (Supp 41, 2006), pp S-82, S-85 to S-87, the authors stated:

              The etiology of WG remains unknown. Based on a growing number of
       epidemiologic investigations carried out during the last 15 years, current
       understanding is that of a complex disease resulting from the interplay among
       multiple genetic and environmental risk factors.

                                                 ...

               Analytic epidemiology aims to identify the determination of disease
       occurrence with putative risk factors commonly falling into 2 major categories:
       genetics and environment. In that context, the term “environment” is generally
       used to designate all non-genetic variables . . . .

                                                 ...

               Genetic predisposition to WG is suggested by ethnic variation . . . and by
       reports of familial aggregation . . . .

                                                 ...

               [S]tudies are consistent in finding positive associations between crystalline
       silica exposure and risk of WG . . . and exposure to silica. . . . Exposure to
       industrial pollutants such as mercury, lead, and cadmium had been found among
       patients with WG but these associations were weak or statistically non-significant.
       Another study revealed exposure to pesticides, particulate matter, or fumes as
       potential risk factors for WG.

        ANCA-associated vasculitides comprise WG and “environmental factors have been
considered important in the development of ANCA, including: silica exposure, bacterial
infection [and] in particular Staphylococcus aureus, viral infection . . ., and exposure to drugs
such as propylthiouracil.” Chen and Kallenberg, The environment, geoepidemiology and ANCA-
associated vasculitides, 9 Autoimmunity Reviews (2010), pp A293-A294; see also



2
  All medical and scientific articles and literature cited in this opinion were submitted to and filed
in the trial court for purposes of the motion in limine.


                                                 -3-
Staphylococcus aureus, T-cell repertoire, and Wegener’s granulomatosis, 68 Joint Bone Spine at
373 (“The many environmental factors capable of inducing the production of ANCAs or
triggering true vasculitis include toxic substances (silica), drugs . . . , and others.”). “A case-
control study carried out at the National Institutes of Health (NIH) revealed an association with
exposure to fumes or particulates and pesticides in patients with WG compared with healthy or
rheumatic disease controls” and “exposure to metal and welding fumes has been reported to
increase the risk of . . . WG . . . .” Lane, Watts, Bentham, Innes, and Scott, Are Environmental
Factors Important in Primary Systemic Vasculitis?, 48 Arthritis & Rheumatism #3 (March
2003), pp 814-815. “A history of high solvent exposure at any time was associated with . . .
WG.”       Id. at 818.      In Duna, Cotch, Galperin, Hoffman, and Hoffman, Wegener’s
granulomatosis: role of environmental exposures, 16 Clinical and Experimental Rheumatology
(November-December 1998), p 669, the authors stated that while the etiology of WG remained
unknown, “[t]he predominant involvement of the airways and the presence of neutrophilic
alveolitis at disease onset have led us to postulate that an inhaled agent may trigger the onset of
WG.” In their study, the authors found that, as between WG and certain control groups,
“[s]tatistically significant differences occurred [greater in the WG group] in regard to . . .
vocational exposure to fumes or particulate materials . . ., residential exposure to particulate
materials from construction . . ., and occupational exposure to pesticides[.]” Id. The authors also
noted that one of several indicators reflecting the onset of WG is sinusitis of more than two
months’ duration. Id. at 670.

        With respect to the apparent link between pesticides and WG, plaintiffs submitted
scientific articles and literature regarding phosphorous and pesticides, showing that various
forms of phosphorous are common components of pesticides. Centers for Disease Control and
Prevention, Organophosphorus Insecticides: Dialkyl Phosphate Metabolites, Biomonitoring
Summary, National Biomonitoring Program (July 2013), p 1 (“Organophosphorus insecticides . .
. have accounted for a large share of all insecticides used in the United States.”); GoodGuide,
Organophosphate Pesticides: Dialkyl Phosphate Metabolites, Scorecard (2011), p 1
(“Organophosphate pesticides account for about half of the insecticides used in the United
States.”); Betteridge, Thompson, Baker, and Kemp, Photoelectron Spectra of Phosphorus
Halides, Alkyl Phosphites and Phosphates, Organo-Phosphorus Pesticides, and Related
Compounds, 44 Analytical Chemistry #12 (October 1972), p 2005.

        We now turn to Dr. Gershwin’s deposition testimony. He testified that “we know that
autoimmunity, including [WG], occurs from a combination of genetic susceptibility and
environmental factors.” When Dr. Gershwin was asked about environmental factors or
chemicals in relation to autoimmunity, he observed that “[i]f we’re referring to [WG], for
example, we know that materials that alter the mucosal airway, whether it’s superantigens,
whether it’s silica exposure, whether it’s chemicals and certain hydrocarbons and solvents and
pesticides[,] have been shown to be associated with patients who develop [WG].” Dr. Gershwin
conceded that there was no literature that specifically indicated that phosphoric acid causes or
contributes to WG. But he noted that one must look to “mechanisms of action” and “depend by
analogy on the science which has already been done and peer reviewed on environmental agents,
including the epidemiological data on solvents, hydrocarbons, agricultural products, [and] silica




                                                -4-
in ANCA-positive patients.”3 He also stated a few times that there would be no studies in which
a person was experimentally exposed to phosphoric acid, as to conduct such testing would be
unethical.

        Dr. Gershwin testified that many solvents and pesticides contain phosphorus or
phosphates, and he accurately noted a couple of times that silicon and phosphorus are next to
each other on periodic table of elements (numbers 14 and 15 respectively), although he did not
elaborate on the relevancy of this fact, simply implying a similarity in properties.4 Dr. Gershwin
then testified:

              Well, many of the hydrocarbons contain phosphates as well. I already
       explained to you what the periodic table is. And incidentally, it’s not really the
       phosphates that are the basis of my opinion. It’s the phosphoric acid and what
       happens when it goes in solution, and I think that’s what’s critical. . . . Mrs.
       Walters presented with an acute onset, . . . with a very high-titer ANCA . . . . We
       had an advantage on her in understanding etiology that we won’t have in people
       that have a more chronic exposure. Because, in fact, the silica exposure data
       shows it’s not necessarily the duration of exposure as it is the intensity of an
       exposure. And of course, in the eight hours she had a very intense exposure.

                                               ...

                So Mrs. Walters was exposed [o]n . . . February 11th, thereabouts. Her
       first sort of signs are about three or four weeks later. Even though temporal
       association by itself should not be the only criteria in this case, it is the perfect
       criteria for a primary immune response. Meaning if I were to immunize you with
       an antigen and ask how long it would take you to make a primary IGG
       [immunoglobulin] response, the time period in which she manifested the sinus
       symptoms is absolutely out of a textbook of immunology.

               And because her disease began with her sinus symptoms and then became
       this incredible immunological storm that crescendoed into her upper airway
       issues, her failures, her respiratory distress . . . .

                                               ...




3
  The literature indicated that not all patients with active WG have ANCAs present. Wegener’s
granulomatosis: role of environmental exposures, 16 Clinical and Experimental Rheumatology
at 673. However, with respect to Walters, Dr. Gershwin testified that she “had a very high-titer
ANCA.”
4
  Dr. Gershwin did indicate that “they have a number of interesting properties, including
isoelectric focusing and so forth.” We appreciate that the particular arrangement of the elements
on the periodic table is based on various properties of the elements.


                                               -5-
              So you then go back to the primary immune response, you have
       phosphoric acid, an[] intense exposure, incredible electrophilic agent that is not
       supposed to be exposed to water. She puts it in her mouth, and she leaves it there.
       And now you present when she finally is evaluated with a very high-titer ANCA.
       You don’t usually have that scenario.

                                                ...

                [W]hen I look at the potency and the chemistry of the phosphoric acid in
       the etching solution, it’s just above and beyond anything that I can even compare
       it to. I mean, this was an incredible inflammatory insult. . . . [When] we look at
       Mrs. Walters and we look at the chemistry of what she was exposed to, the time
       period of her clinical presentation, the safety data sheets [for the etching solution],
       the data that’s already available on environmental factors, this is a very important
       case for the medical literature.

                                                ...

               [We] really have a plausible scientifically acceptable mechanism of action.

                                                ...

              So I think what happened is phosphoric acid hits water, disassociates,
       produces an incredible inflammatory response, including neutrophil. That’s why
       she had the symptoms she had. The neutrophils enter the area, they marginate
       acutely as they are supposed to, they degrade, the myeloperoxidase neutrophilic
       antigens get released, she mounts an immune response, she boosts it, and that’s
       why she has . . . WG.

        Dr. Gershwin further testified that sinusitis does not cause WG; rather, sinusitis is a
manifestation, sign, and symptom of WG. He opined that Walters “would not have got [WG]
had it not been for the etching solution.” Dr. Gershwin clarified that he could not state that she
would not have suffered WG in the future, given her predisposition to WG and the possibility of
another type of environmental exposure; however, he emphasized that Walters would not have
suffered WG when she did but for the exposure to the etching solution. Dr. Gershwin opined
that WG would reduce Walters’ life span by ten 10 years.

         Defendants filed a motion in limine to preclude Dr. Gershwin’s testimony. They argued
that there was no scientific support for his conclusion that the etching solution is an
environmental catalyst that, along with Walters’ alleged predisposition to WG, caused the onset
of her WG. Defendants additionally contended that Dr. Gershwin’s testimony regarding a causal
connection between the etching solution / phosphoric acid and WG failed to meet the test for
reliability under MCL 600.2955. The trial court granted the motion, ruling that Dr. Gershwin’s
testimony was not reliable under MRE 702 and not supported by the scientific and medical data.
The trial court noted a few times that the articles and literature expressed that the etiology or
cause of WG remained unclear and unknown. The trial court also concluded that the scientific
and medical data relied on by plaintiffs failed to show a connection between phosphorus,
phosphates, or phosphoric acid and the chemicals and environmental factors that had been
                                                -6-
identified in literature as being associated with WG; and even that association was tenuous.
Plaintiffs appeal by leave granted.

       In Chapin v A & L Parts, Inc, 274 Mich App 122, 126-127; 732 NW2d 578 (2007), this
Court set forth the applicable standard of review and the general principles that are implicated
when examining the admissibility of expert testimony:

                 This Court reviews for an abuse of discretion a trial court's determination
         of the qualifications of a proposed expert witness. This Court likewise reviews for
         an abuse of discretion a trial court's decision whether to admit evidence, although
         admission of legally inadmissible evidence is necessarily an abuse of
         discretion. The interpretation of an evidentiary rule is reviewed de novo in the
         same manner as the examination of the meaning of a court rule or a statute. Rules
         of evidence are construed in the same way as statutes.

                Before a trial court may admit any expert testimony, the trial court is
         required by MRE 702[5] to ensure that each aspect of an expert witness's
         proffered testimony—including the data underlying the expert's theories and the
         methodology by which the expert draws conclusions from that date—is reliable.
         While the exercise of this gatekeeper role is within a court's discretion, a trial
         judge may neither abandon this obligation nor perform the function inadequately.
         The plain language of MCL 600.2955(1)[6] establishes the Legislature's intent to


5
    MRE 702 provides:
                 If the court determines that 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 if
         (1) the testimony is based on sufficient facts or data, (2) the testimony is the
         product of reliable principles and methods, and (3) the witness has applied the
         principles and methods reliably to the facts of the case.


6
    MCL 600.2955(1) provides:
                 In an action for the death of a person or for injury to a person or property,
         a scientific opinion rendered by an otherwise qualified expert is not admissible
         unless the court determines that the opinion is reliable and will assist the trier of
         fact. In making that determination, the court shall examine the opinion and the
         basis for the opinion, which basis includes the facts, technique, methodology, and
         reasoning relied on by the expert, and shall consider all of the following factors:

                 (a) Whether the opinion and its basis have been subjected to scientific
         testing and replication.



                                                 -7-
       assign the trial court the role of determining . . . whether proposed scientific
       opinion is sufficiently reliable for jury consideration. The United States
       Supreme Court emphasized that the inquiry is flexible and focused solely on
       principles and methodology rather than ultimate conclusions, and its overarching
       subject is the scientific validity—and thus the evidentiary relevance and
       reliability—of the principles that underlie a proposed submission. [Citations,
       quotation marks, and alteration brackets omitted.]

       In Chapin, this Court recognized the “Sir Bradford Hill” (SBH) methodology for
examining causation, which methodology goes beyond just using epidemiological data and is
primarily intended to determine cause and effect. Id. at 133. The SBH methodology contains
nine criteria: strength of association; temporality (cause must precede effect); biologic or
response gradient (basic toxicological knowledge); consistency; specificity, biological
plausibility; coherence; experimental evidence; and analogy. Id. at 133-134.

        Here, Dr. Gershwin’s opinion that Walters’ exposure to the phosphoric acid in the
etching solution caused her WG was predicated on: (1) the caustic nature of phosphoric acid; (2)
phosphoric acid being a WG-triggering environmental factor or chemical; (3) the intensity and
duration of the phosphoric acid exposure (overnight while Walters slept); (4) the area of
exposure (inside the mouth where moisture exists); (5) the textbook timing of the presentation of
an immune response in relationship to the date of exposure and the overall chronology of events;
(6) the incredible extent of the immune response (a very high-titer ANCA); (7) the manifestation
              (b) Whether the opinion and its basis have been subjected to peer review
       publication.

              (c) The existence and maintenance of generally accepted standards
       governing the application and interpretation of a methodology or technique and
       whether the opinion and its basis are consistent with those standards.

              (d) The known or potential error rate of the opinion and its basis.

              (e) The degree to which the opinion and its basis are generally accepted
       within the relevant expert community. As used in this subdivision, “relevant
       expert community” means individuals who are knowledgeable in the field of
       study and are gainfully employed applying that knowledge on the free market.

               (f) Whether the basis for the opinion is reliable and whether experts in
       that field would rely on the same basis to reach the type of opinion being
       proffered.

               (g) Whether the opinion or methodology is relied upon by experts outside
       of the context of litigation.




                                               -8-
and duration of a classic WG symptom, sinusitis; (8) Walters’ predisposition to WG; and (9) the
medical and scientific literature, directly or by analogy. Dr. Gershwin’s analysis employed many
of the criteria associated with the SBH methodology; it was a cause and effect methodology.
        With respect to the caustic nature of phosphoric acid, this was established by the product
safety data sheet regarding the etching solution, which indicated that it is corrosive, can cause
chemical burns, permanent tissue damage, swallowing difficulties, vomiting, diarrhea, and
possible shock, is harmful if swallowed, can irritate the respiratory system, and that it should not
be exposed to moist air or water. Given that Walters slept overnight with a dental tray in her
mouth that was filled with the etching solution, there is no dispute regarding the intensity,
duration, and location of the exposure. There also does not appear to be any dispute concerning
the claimed textbook timing or chronology of the presentation of an immune response in
relationship to the date of exposure, nor as to Walters’ very high-titer ANCA. Next, the medical
and scientific literature cited above supports the proposition that sinusitis can be a manifestation
of the onset of WG, especially where it is of long duration, as was the case with Walters.

        On the issue of the role of environmental factors and genetic influences relative to
causation, as reflected above, the medical and scientific literature did indeed indicate that the
etiology of WG remains unclear and unknown. However, when read in context, this proposition
was clearly meant to indicate that a “definitive” or “absolutely certain” etiology is unclear and
unknown. In Staphylococcus aureus, T-cell repertoire, and Wegener’s granulomatosis, 68 Joint
Bone Spine at 373, the authors stated that “[t]he pathogenesis of WG and other vasculitides
associated with ANCAs . . . probably involves an interaction between a genetic susceptibility
and environmental factors.” (Emphasis added.) In Epidemiology of Wegener’s granulomatosis:
Lessons from descriptive studies and analyses of genetic and environmental risk determinants,
24 Clinical and Experimental Rheumatology at S-82, S-85 to S-87, the authors, while
acknowledging that the “etiology of WG remains unknown,” nonetheless stated that “[b]ased on
a growing number of epidemiologic investigations carried out during the last 15 years, current
understanding is that of a complex disease resulting from the interplay among multiple genetic
and environmental risk factors.” (Emphasis added.) Those authors also indicated that “studies
are consistent in finding positive associations between crystalline silica exposure and risk of
WG.” (Emphasis added.) In The environment, geoepidemiology and ANCA-associated
vasculitides, 9 Autoimmunity Reviews at A293-A294, the authors stated that “environmental
factors have been considered important in the development of ANCA.” (Emphasis added.) And
in Wegener’s granulomatosis: role of environmental exposures, 16 Clinical and Experimental
Rheumatology at 669, the authors noted that while the etiology of WG remained unknown, “[t]he
predominant involvement of the airways and the presence of neutrophilic alveolitis at disease
onset have led us to postulate that an inhaled agent may trigger the onset of WG.”

       Accordingly, while not definitive, there is medical and scientific literature indicating that
the probable or likely cause of WG is a combination of environmental and genetic factors. We
observe that plaintiffs, in order to succeed, are not required to definitively establish a causal link
between the exposure and WG.7 Moreover, the inquiry regarding whether proposed scientific


7
 “To establish a prima facie case of negligence, a plaintiff must prove four elements: (1) a duty
owed by the defendant to the plaintiff, (2) a breach of that duty, (3) causation, and (4) damages.”

                                                 -9-
opinion is sufficiently reliable for a jury to consider “is flexible and focused solely on principles
and methodology rather than ultimate conclusions[.]” Chapin, 274 Mich App at 126-127
(emphasis added). The trial court here made an error of law in analyzing the question of the
admissibility of Dr. Gershwin’s testimony by effectively requiring plaintiffs to establish
causation and their case prior to trial and to do so definitively. And the trial court further erred
by failing to take into consideration Dr. Gershwin’s legitimate reliance on the nature, duration,
intensity, and location of the exposure, the temporal proximity of the immune response to the
date of exposure, and the duration and nature of an expected manifestation of WG, i.e., a lengthy
battle with sinusitis, which all played a role in Dr. Gershwin’s overall analysis.

        With respect to the lack of medical or scientific literature specifically connecting an
exposure to phosphoric acid with WG, there was literature, cited above, reflecting the prevalence
of phosphates in pesticides and showing a statistically significant association between pesticides
and the development of WG. Organophosphorus Insecticides: Dialkyl Phosphate Metabolites,
Biomonitoring Summary, National Biomonitoring Program, at 1; Are Environmental Factors
Important in Primary Systemic Vasculitis?, 48 Arthritis & Rheumatism at 814-815; Wegener’s
granulomatosis: role of environmental exposures, 16 Clinical and Experimental Rheumatology
at 669. Also, while not expressly stated, it appears that Dr. Gershwin’s view was that phosphoric
acid is comparable to silica, which has been linked to WG, in the context of environmental
factors that cause WG. Regardless, the lack of a specific study looking at direct exposures to
phosphoric acid is understandable considering the ethical dilemma posed by conducting such a
study. And we find our situation analogous to that in Chapin, where “a number of
epidemiological studies had analyzed mesothelioma among automobile brake mechanics and
failed to show an association between asbestos-based automobile brake products and
mesothelioma.” Chapin, 274 Mich App at 135. This Court, nonetheless, allowed the plaintiffs’
expert to testify about a causal link between exposure to asbestos-based automobile brake
products and mesothelioma, considering all of the SBH criteria supporting causation. Id. at 140.
The Chapin panel ruled:

              This case does not present a situation involving questionable or absent
        epidemiological evidence coupled with questionable or absent other evidence, or



Case v Consumers Power Co, 463 Mich 1, 6; 615 NW2d 17 (2000). The causation element
encompasses both cause in fact and proximate or legal cause. Id. at n 6. “The cause in fact
element generally requires showing that ‘but for’ the defendant’s actions, the plaintiff’s injury
would not have occurred.” Skinner v Square D Co, 445 Mich 153, 163; 516 NW2d 475 (1994).
It is not sufficient to proffer “a causation theory that, while factually supported, is, at best, just as
possible as another theory.” Id. at 164. A “plaintiff must present substantial evidence from
which a jury may conclude that more likely than not, but for the defendant's conduct, the
plaintiff's injuries would not have occurred.” Id. at 164-165 (emphasis added). But “litigants do
not have any right to submit an evidentiary record to the jury that would allow the jury to do
nothing more than guess.” Id. at 174. The Skinner Court further observed that “‘[t]he evidence
need not negate all other possible causes’” and absolute certainty on causation is not required.
Id. at 166, quoting 57A Am Jur 2d, Negligence, § 461, p 442.


                                                  -10-
       coupled with an “expert” who actually lacks the requisite qualifications.[8] Rather,
       this is a case involving strong and undisputed support for . . . [plaintiffs’ expert’s]
       position, coupled with fairly consistent yet potentially questionable contradictory
       evidence, depending on which expert is to be believed. Although clearly not
       universally accepted, and although unsupported by epidemiological studies that
       may or may not be flawed, . . . [his] opinion is certainly objective, rational, and
       based on sound and trustworthy scientific literature. [Id.]

       As indicated, in Chapin, there were studies that actually showed no correlation between
exposure to asbestos-based automobile brake products and mesothelioma, yet the expert was
allowed to testify, and here there is no indication that there exist any studies showing that
phosphoric acid does not cause WG. Furthermore, as in Chapin, there was other unquestionable
cause-and-effect evidence showing a link between the exposure and WG; plus, there are
epidemiological studies generally supporting Dr. Gershwin’s opinion. We also note that
defendants do not counter Dr. Gershwin’s assertion that when phosphoric acid comes into
contact with moisture, such as it did inside Walters’ mouth, it produces an incredible
inflammatory response. Again, the product safety data sheet regarding the etching solution
provided that it should not be exposed to moist air or water, is harmful if swallowed, and can
cause respiratory distress. We are not prepared to preclude Dr. Gershwin’s testimony simply
because there is not a specific study showing that exposure to phosphoric acid causes WG.

        In sum, Dr. Gershwin’s testimony was based on sufficient facts or data, it was the product
of reliable principles and methods, and Dr. Gershwin applied the principles and methods reliably
to the facts of the case, MRE 702. The trial court erred in granting defendants’ motion in limine.
The trier of fact will ultimately be free to weigh Dr. Gershwin’s opinion on causation and accept
or reject it. See Chapin, 274 Mich App at 140 (“[D]eciding this case at an evidentiary hearing,
depriving the jury of the opportunity to fulfill its proper role as fact-finder, would be
inappropriate.”).

        Reversed and remanded for further proceedings consistent with this opinion. We do not
retain jurisdiction. Having fully prevailed on appeal, plaintiffs are awarded taxable costs under
MCR 7.219.

                                                              /s/ William B. Murphy
                                                              /s/ Deborah A. Servitto




8
 There is no dispute that, as found by the trial court, Dr. Gershwin is highly qualified to give an
opinion in this area of medicine; his CV is extremely impressive.


                                                -11-
