Kannankeril v. Terminix International, Inc. , 128 F.3d 802 ( 1997 )


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  •                                                                                                                            Opinions of the United
    1997 Decisions                                                                                                             States Court of Appeals
    for the Third Circuit
    10-17-1997
    Kannankeril v. Terminix Intl Inc
    Precedential or Non-Precedential:
    Docket
    96-5818
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    Recommended Citation
    "Kannankeril v. Terminix Intl Inc" (1997). 1997 Decisions. Paper 243.
    http://digitalcommons.law.villanova.edu/thirdcircuit_1997/243
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    Filed October 17, 1997
    UNITED STATES COURT OF APPEALS
    FOR THE THIRD CIRCUIT
    No. 96-5818
    CHARLES KANNANKERIL; MARY KANNANKERIL,
    individually and as next friend of Charlene and
    Crystal Kannankeril; CHARLENE KANNANKERIL;
    CRYSTAL KANNANKERIL
    v.
    TERMINIX INTERNATIONAL, INC.; TM SPECIAL
    PARTNERS, INC.; TERMINIX MGP, INC., General Partners
    of the Terminix International Company Limited
    Partnership; TERMINIX INTERNATIONAL; DOW
    CHEMICAL U.S.A.; WHITMIRE RESEARCH
    LABORATORIES, INC.; FORD CHEMICAL & SERVICE,
    INC.; DENNIS BUTTIMORE, c/o Terminix International;
    THE TERMINIX INTERNATIONAL COMPANY
    LIMITED PARTNERSHIP
    Mary Kannankeril, Individually and as
    Next Friend of Charlene Kannankeril,
    Appellant.
    On Appeal from the District Court
    for the District of New Jersey
    (D.C. Civil Action No. 92-cv-03150)
    Argued on July 17, 1997
    Before: SLOVITER, Chief Judge, ROTH and
    MICHEL,1 Circuit Judges
    _________________________________________________________________
    1. Honorable Paul R. Michel, United States Court of Appeals for the
    Federal Circuit, sitting by designation.
    (Opinion filed October 17, 1997)
    Evan T. Lawson, Esq. (Argued)
    Christopher N. Cook, Esq.
    Lawson & Weitzen
    425 Summer Street
    Boston, MA 02210
    Attorneys for Appellants
    Kevin E. Wolff, Esq. (Argued)
    Robert W. Muilenburg, Esq.
    McElroy, Deutsch & Mulvaney
    1300 Mount Kemble Avenue
    P.O. Box 2075
    Morristown, NJ 07962-2075
    Attorneys for Appellee Terminix
    International
    OPINION OF THE COURT
    ROTH, Circuit Judge.
    The Kannankerils, Dr. Mary Kannankeril, her husband,
    Charles, and their children, Charlene and Crystal, sued a
    pest exterminator, the Terminix International Company L.P.
    ("Terminix"), seeking damages for injuries allegedly arising
    out of the application of pesticides to their residence. The
    district court found the opinion of Dr. Benjamin Gerson,
    the medical expert of Dr. Mary Kannankeril, to be
    unreliable and unsupported by facts. Having excluded Dr.
    Gerson's opinion, the district court held that Dr.
    Kannankeril had failed to produce any evidence that her
    cognitive impairment had been caused by exposure to
    pesticides applied by Terminix. The court granted summary
    judgment in favor of Terminix. The admissibility of Dr.
    Gerson's opinion is the sole issue on which the
    Kannankerils have appealed. They argue that the district
    court erroneously excluded the testimony of Dr. Gerson.
    We conclude that the district court improperly exercised
    its gatekeeping role by excluding Dr. Gerson's testimony.
    2
    Accordingly, we will vacate that portion of the order of the
    district court, granting summary judgment against Dr.
    Mary Kannankeril on this point, and we will remand this
    case for further proceedings consistent with this opinion.2
    I. BACKGROUND
    The Kannankerils entered into a one-year contract with
    Terminix on May 30, 1989, for the control of carpenter ants
    through the application of pesticides to certain interior
    portions and the outside deck of the Kannankerils'
    residence. From May 31, 1989, through October 5, 1990,
    Terminix treated the Kannankeril residence on at least
    twenty occasions at intervals ranging from once a month to
    twice in a three day period. Terminix applied pesticides,
    containing Dursban, until the Kannankerils canceled the
    service on October 5, 1990.
    Dursban, the active ingredient in certain pesticides used
    by Terminix, is a formulation of chlorpyrifos, an
    organophosphate poison. The organophosphates kill insects
    by inhibiting the normal breakdown of acetylcholine, which
    functions as a neurotransmitter in several life forms,
    including humans. The Kannankerils argue that despite the
    well-known chronic effects of chlorpyrifos, Dursban was
    sprayed excessively and improperly in their home. For
    example, Dursban was sprayed on the cooking range,
    around the dishwasher, and on the baseboard heater.
    Dursban was also sprayed in cupboards where pots and
    pans were stored. Terminix, however, claims that any liquid
    pesticide that was applied consisted almost entirely of
    water, with minute concentrations of liquid pesticide added
    to make the final active solution.
    The Kannankerils' suit against Terminix involved alleged
    injury to Dr. Mary Kannankeril, a former Medical Director
    of Psychiatric Emergency Services at Saint Mary's Hospital
    in Passaic, New Jersey. Dr. Kannankeril claims to suffer
    wide-ranging physiological and cognitive symptoms from
    _________________________________________________________________
    2. Our decision, vacating the summary judgment against Dr.
    Kannankeril, is without prejudice to any motion for summary judgment
    on other grounds which Terminix may bring.
    3
    exposure to the pesticides, including Dursban, applied by
    Terminix.3 The symptoms first appeared in August 1990,
    over one year after Terminix began its service. The
    Kannankerils did not relate Dr. Kannankeril's symptoms
    with Terminix's ongoing pesticide applications until October
    1990. After the entire family developed a rash, the
    Kannankerils began to suspect Dursban as the cause of
    their problems. When the Kannankerils complained of a
    strong odor in their home after the last application,
    Terminix sent Service Master to clean the Kannankerils'
    residence. In July 1991, nine months after the last
    application of pesticide, the Kannankerils requested that
    the New Jersey Department of Environmental Protection
    ("DEP") test their residence for the existence of pesticides.
    The DEP collected air samples from the residence on July
    10, 1991. An analysis of the samples indicated non-
    detectable levels of pesticides.
    Dr. Kannankeril allegedly developed chronic toxicity
    related to exposure to chlorpyrifos and became sensitized to
    multiple other chemicals so that further exposure to
    organophosphates would result in disabling physical
    problems. As a result of her ill health, she gave up her
    hospital position in March, 1993, and now sees patients
    only in an office at home.
    Plaintiffs named Dr. Benjamin Gerson, M.D., to testify as
    a medical expert to establish that exposure to Dursban
    caused Dr. Kannankeril's injury.4 Dr. Gerson provided the
    following opinion:
    _________________________________________________________________
    3. Only the causation of Dr. Kannankeril's cognitive impairment remains
    an issue in the case. These cognitive deficits include memory loss,
    concentration loss, sleeplessness, general anxiety, and headaches. Her
    other alleged physical symptoms included insomnia, numbness, muscle
    twitching, pain in muscles and joints, vaginal bleeding, urinary
    incontinence, nausea, skin rashes, and depigmentation patches
    throughout her body.
    4. Dr. Gerson's qualifications included: Physician certified by the
    American Board of Toxicology and the American Board of Pathology;
    Director of the Boston University School of Medicine's Laboratory of
    Analytical Toxicology and Director of the Research Data Worldwide
    Clinical Laboratory; Consultant to the Food and Drug Administration's
    4
    The temporal relationship and the nature of her
    complaints lead me to conclude that with reasonable
    medical certainty, the cause of Dr. Kannankeril's
    Central Nervous System manifestations of toxicity is
    exposure to Dursban in 1989 to 1990.
    App. at 51.5 Dr. Gerson is the only medical expert proffered
    by the Kannankerils on causation and his opinion is limited
    to the causation of Dr. Kannankeril's cognitive impairment.
    His findings are based on Dr. Kannankeril's account of her
    cognitive symptoms and on a report prepared by Dr. Ellen
    Grober, a neuropsychologist who examined Dr.
    Kannankeril. Dr. Gerson also relied on a summary report of
    the times and amounts of Dursban applications to the
    Kannankeril home as well as on his general experience and
    readings, general medical knowledge, standard textbooks,
    and standard references.
    II. STANDARD OF REVIEW
    A district court's ruling on admissibility of expert
    testimony is reviewed for abuse of discretion. Government of
    the Virgin Islands v. Sanes, 
    57 F.3d 338
    , 341 (3d Cir.
    1995); In re Paoli R.R. Yard PCB Litig., 
    35 F.3d 717
    , 749 (3d
    Cir. 1994). To the extent that the district court's ruling
    turns on interpretation of the Federal Rules of Evidence,
    _________________________________________________________________
    Center for Devices and Radiological Health; Professor of Pathology and a
    Professor of Pharmacology & Experimental Therapeutics at Boston
    University; Instructor in Pathology, Harvard Medical School; Special
    Lecturer in Clinical Laboratory Science, Northeastern University;
    Assistant Professor of Pathology, Harvard Medical School; Associate
    Professor of Pathology, Harvard Medical School; Director of Clinical
    Chemistry and Toxicology at Veterans Affairs Medical Center in Boston,
    Massachusetts.
    5. Under New Jersey law, medical expert testimony must be made with
    a reasonable degree of certainty. See Bondi v. Pole, 
    246 N.J. Super. 236
    (App. Div. 1991); Vuocolo v. Diamond Shamrock Chemical Co., 
    240 N.J. Super. 289
     (App.Div. 1990); Johnesee v. The Stop & Shop Companies,
    
    174 N.J. Super. 426
     (App.Div. 1980). New Jersey's rule should govern in
    the present case since it is a substantive law that is part of the
    appellants' burden of proof. See In re Paoli R.R. Yard PCB Litig., 
    35 F.3d 717
    , 752 (3d Cir. 1994).
    5
    our review is plenary. United States v. Velasquez, 
    64 F.3d 844
    , 848 (3d Cir. 1995); Paoli, 
    35 F.3d at 749
    . We review
    the district court's findings of fact under a clearly
    erroneous standard. Velasquez, 
    64 F.3d at 848
    .
    III. DISCUSSION
    A. Standard of Admissibility for Expert Testimony
    Under the Federal Rules of Evidence, it is the role of the
    trial judge to act as a "gatekeeper" to ensure that any and
    all expert testimony or evidence is not only relevant, but
    also reliable. Daubert v. Merrell Dow Pharmaceuticals, Inc.,
    
    509 U.S. 579
    , 589. (1993). The Rules of Evidence embody
    a strong and undeniable preference for admitting any
    evidence which has the potential for assisting the trier of
    fact. See Holbrook v. Lykes Bros. S.S. Co., 
    80 F.3d 777
    , 780
    (3d Cir. 1996). Rule 702, which governs the admissibility of
    expert testimony, has a liberal policy of admissibility. See
    Holbrook, 80 F.3d at 780; Paoli, 
    35 F.3d at 741
    .
    Rule 702 has three major requirements: (1) the proffered
    witness must be an expert; (2) the expert must testify about
    matters requiring scientific, technical or specialized
    knowledge; and (3) the expert's testimony must assist the
    trier of fact. See Paoli, 
    35 F.3d at 741-42
    . The issue of this
    appeal involves the second requirement of the expert's
    testimony. In interpreting this second requirement, we have
    concluded that "an expert's testimony is admissible so long
    as the process or technique the expert used in formulating
    the opinion is reliable." 
    Id.
     at 742 (citing Daubert, 
    113 S.Ct. at 2794-95
    ). In order for the expert testimony to be
    "reliable," we have required that the testimony be based on
    the "methods and procedures of science," rather than on
    "subjective belief or unsupported speculation." Paoli, 
    35 F.3d at 744
    . Moreover, Daubert does not set up a test of
    which opinion has the best foundation, but rather whether
    any particular opinion is based on valid reasoning and
    reliable methodology. Admissibility decisions focus on the
    expert's methods and reasoning; credibility decisions arise
    after admissibility has been determined. See Paoli, 
    35 F.3d at 743-46
    .
    6
    There are several factors that a district court should take
    into account in evaluating whether a particular scientific
    methodology is reliable. See Paoli, 
    35 F.3d at 742
    .6
    Although these factors are neither exhaustive nor
    applicable in every case, they provide a convenient starting
    point for analyzing the opinion of Dr. Gerson. Our inquiry
    focuses on principles and methodology and not on the
    conclusions they generate. 
    Id. at 744
    . The analysis of the
    conclusions themselves is for the trier of fact when the
    expert is subjected to cross-examination. 
    Id.
     The
    Kannankerils needed to demonstrate by a preponderance of
    evidence only that Dr. Gerson's opinion was based on "good
    grounds." 
    Id.
    B. Reliability of Dr. Gerson's Testimony
    The district court refused to admit Dr. Gerson's
    testimony because of insufficient factual foundation to
    prove that the cause of Dr. Kannankeril's cognitive
    impairment was exposure to Dursban. We conclude,
    however, that Dr. Gerson's opinion meets the requirements
    for the admission of expert testimony under Rule 702 of the
    Federal Rules of Evidence, as set forth in Daubert and
    interpreted by us in Paoli.
    1. Differential Diagnosis
    In its opposition to Dr. Gerson's testimony, Terminix has
    _________________________________________________________________
    6. These nonexclusive guidelines, drawn from Daubert and this Court's
    opinion in United States v. Downing, 
    753 F.2d 1223
     (3d Cir. 1985),
    include:
    (1) whether a method consists of a testable hypothesis; (2) whether
    the method has been subject to peer review; (3) the known or
    potential rate of error; (4) the existence and maintenance of
    standards controlling the technique's operation; (5) whether the
    method is generally accepted; (6) the relationship of the technique
    to
    methods which have been established to be reliable; (7) the
    qualifications of the expert witness testifying based on the
    methodology; and (8) the non-judicial uses to which the method has
    been put.
    Paoli, 
    35 F.3d at
    742 n.8.
    7
    emphasized that Dr. Gerson did not himself perform any
    diagnostic medical tests. Terminix argues that Dr. Gerson
    did not employ sufficient diagnostic techniques to have
    good grounds for his conclusions or to have properly
    performed a differential diagnosis. We have recognized
    "differential diagnosis" as a technique that involves
    assessing causation with respect to a particular individual.
    Paoli, 
    35 F.3d at 758
    . Differential diagnosis is defined for
    physicians as "the determination of which of two or more
    diseases with similar symptoms is the one from which the
    patient is suffering, by a systematic comparison and
    contrasting of the clinical findings." STEDMAN'S MEDICAL
    DICTIONARY 428 (25th ed. 1990). The elements of a
    differential diagnosis may consist of the performance of
    physical examinations, the taking of medical histories, and
    the review of clinical tests, including laboratory tests. A
    doctor does not have to employ all of these techniques in
    order for the doctor's diagnosis to be reliable. See Paoli, 
    35 F.3d at 759
    . A differential diagnosis may be reliable with
    less than all the types of information set out above. See 
    id.
    Indeed, as we held in Paoli, "to the extent that the district
    court concluded otherwise [i.e., that a differential diagnosis
    made on less than all types of information cannot be
    reliable], we hold that it abused its discretion." 
    Id.
    Depending on the medical condition at issue and on the
    clinical information already available, a physician may
    reach a reliable differential diagnosis without himself
    performing a physical examination, particularly if there are
    other examination results available. In fact, it is perfectly
    acceptable, in arriving at a diagnosis, for a physician to rely
    on examinations and tests performed by other medical
    practitioners.
    These principles are applicable to the admissibility of
    Dr. Gerson's expert opinion regarding Dr. Kannankeril. The
    district court found that Dr. Gerson never performed any
    clinical tests to support his opinion of causation. Dr.
    Gerson did not "examine, or even speak to" Dr.
    Kannankeril. Instead, Dr. Gerson reviewed the records of
    Dr. Kannankeril's medical history. Dr. Gerson also relied on
    Dr. Grober's report of Dr. Kannankeril's neuropsychological
    complaints and of her cognitive impairment. Terminix does
    8
    not claim that the medical records relied upon by Dr.
    Gerson were incomplete or inaccurate. As noted by this
    Court in Paoli, "evaluation of the patient's medical records
    is a reliable method of concluding that a patient is ill even
    in the absence of a physical examination." 
    Id. at 762
    . A
    doctor needs only one reliable source of information
    showing that a plaintiff is ill; either a physical test or
    medical records will suffice for this. 
    Id. at 762
    . For these
    reasons, the reliability of Dr. Gerson's opinion is not
    necessarily diminished by the fact that he himself did not
    perform a physical examination.
    Moreover, in making his evaluation, Dr. Gerson was
    aware that one test, the cholinesterase blood test, did not
    produce abnormal results. The district court noted that the
    blood test for cholinesterase levels is "the most accepted
    test method for determining exposure to Dursban."
    However, the cholinesterase test result is but one of the
    factors considered by Dr. Gerson. Despite the negative
    results from this test, Dr. Gerson still opined that, as a
    matter of reasonable medical certainty, Dursban had
    caused Dr. Kannankeril's cognitive impairment. It is for the
    jury to decide whether a single cholinesterase test, yielding
    results within normal limits, outweighs the other factors
    relied upon by Dr. Gerson and undermines his opinion.
    This is an issue of credibility, not of admissibility.
    Furthermore, we do not agree with the trial court's
    finding that "every" objective medical test showed normal
    results. The cholinesterase test was not the only clinical
    test performed on Dr. Kannankeril. Dr. Grober, the
    neuropsychologist at the Albert Einstein Medical Center,
    confirmed a diminution in Dr. Kannankeril's cognitive
    abilities.
    In attacking the differential diagnosis performed by the
    plaintiff's expert, the defendant may point to a plausible
    cause of the plaintiff's illness other than the defendant's
    actions. It then becomes necessary for the plaintiff's expert
    to offer a good explanation as to why his or her conclusion
    remains reliable. Paoli, 
    35 F.3d at 762
    . Dr. Gerson,
    however, was never challenged by the presentation of
    alternate diagnoses by other physicians. Moreover,
    Terminix, in challenging Dr. Gerson's opinion, has not
    9
    raised any other theory of causation for Dr. Kannankeril's
    cognitive impairment.7 The record in this case is devoid of
    any alternate diagnosis which Dr. Gerson ignored or failed
    to consider.
    Furthermore, we reject Terminix's argument that Dr.
    Gerson admitted to alternate causes other than exposure to
    Dursban for Dr. Kannankeril's condition. Dr. Gerson had
    testified at his deposition that something other than
    exposure to organophosphates "could" have caused each of
    the individual symptoms displayed by Dr. Kannankeril.
    While, however, an alternate explanation for each of Dr.
    Kannankeril's individual symptoms may exist separately,
    Dr. Gerson concluded with reasonable medical certainty
    that Dursban was the most likely cause of her condition as
    a whole. Terminix's exploration of the cause of each
    individual symptom goes not to the admissibility of the
    evidence but to its weight.
    2. Degree of Exposure
    The Kannankerils also contend that the district erred in
    finding that Dr. Gerson had no knowledge of Dr.
    Kannankeril's degree of exposure to Dursban. According to
    the district court, Dr. Gerson did not know the levels of
    Dursban at the Kannankerils' home at the time of
    exposure, and he did not know the amount of time
    plaintiffs spent in the home. We conclude, however, that
    the district court erred when it failed to recognize that Dr.
    Gerson had sufficient knowledge of exposure from his
    review of Terminix's application records, showing when,
    how much, and where pesticide had been applied.
    Terminix asserts, however, that these application records
    are "unreliable as a matter of law as a tool" to determine
    Dr. Kannankeril's exposure. The trial court agreed and
    ruled that the only information reviewed by Dr. Gerson
    which addressed actual levels of pesticides in the
    _________________________________________________________________
    7. Terminix had, of course, no obligation to present an alternate theory
    of causation in its effort to have Dr. Gerson's opinion excluded. However,
    in determining whether a proper differential diagnosis was conducted, a
    consideration of other diagnoses may be relevant.
    10
    Kannankeril home was the analysis performed by the DEP
    in July 1991, nine months after the last application of
    Dursban. The results of that sampling indicated non-
    detectable levels of pesticides.
    We find that Terminix's assertion is without merit. First,
    there is no expert opinion in the record to establish that an
    ambient air test, particularly an ambient air test performed
    nine months after the final application of Dursban, is the
    only appropriate way in this case to gauge exposure to the
    organophosphate. Moreover, the plaintiffs were prepared to
    offer into evidence the Dursban product label which
    contained warnings such as: "HARMFUL IF SWALLOWED .
    HARMFUL IF ABSORBED THROUGH SKIN . CAUSES EYE
    AND SKIN IRRITATION" and "Throughly wash dishes and
    food handling utensils with soap and water if they become
    contaminated by application of this product. Do not allow
    children or pets to contact treated surfaces until spray has
    dried." App. at 241-43. Under the facts as presented in this
    case, the district judge erred in ruling that an expert may
    rely only on the ambient air test to determine whether Dr.
    Kannankeril had been exposed to Dursban. Instead, all
    factual evidence of the presence of the chemicals in the
    residence should be relevant in forming an expert opinion
    of causation.
    We conclude that it is for the trier of fact to determine
    what weight to give the ambient air test results as an
    indication of exposure. See Joiner v. General Elec. Co., 
    78 F.3d 524
    , 534 (11th Cir. 1996) (reversing exclusion of
    expert opinions that plaintiffs' exposure to certain
    chemicals caused his lung cancer where there were issues
    of fact whether plaintiff was actually exposed to the
    chemicals so that summary judgment based on a finding of
    no exposure was inappropriate). The issue whether an
    ambient air test should be given more weight than pesticide
    application records goes to the weight rather than the
    admissibility of evidence. See United States v. Velasquez, 
    64 F.3d 844
    , 848 (3d Cir. 1995) (citing United States v.
    Jakobetz, 
    955 F.2d 786
    , 800 (2d Cir. 1992)). The trial judge
    must be careful not to mistake credibility questions for
    admissibility questions.
    11
    3. Peer Review and Publication
    Two other factors that a district court can take into
    account in assessing reliability are peer-review and
    publication. They may not, however, in every case be
    necessary conditions of reliability. See Daubert, 
    509 U.S. at 593
    ; Paoli, 
    35 F.3d at 742
    . In the instant case, Dr. Gerson
    admitted that he has not produced any publication on
    organophosphates. Because the toxic effects of
    organophosphates on humans are well recognized by the
    scientific community, however, Dr. Gerson's opinion is not
    a novel scientific theory regarding organophosphates.8
    Instead, Dr. Gerson merely reported that Dr. Kannankeril
    exhibited the "signs and symptoms of chronic toxicity
    related to exposure to chlorpyrifos (Dursban)." Thus,
    although Dr. Gerson did not write on the topic, his opinion
    is supported by widely accepted scientific knowledge of the
    harmful nature of organophosphates. See also McCullock v.
    H.B. Fuller Co., 
    61 F.3d 1038
    , 1042 (2d Cir. 1995) (holding
    that peer review and publication or general acceptance of
    an expert's theory goes to the weight of the testimony
    rather than its admissibility).
    Based on the record before us, we conclude that
    Dr. Gerson's opinion on causation has a factual basis
    and supporting scientific theory. Dr. Gerson based his
    opinion on Dr. Kannankeril's medical records, Dr. Grober's
    reports confirming her medical condition, and Terminix's
    application receipts. He also relied on general experience
    and readings, general medical knowledge, standard
    textbooks, and standard references. After considering all
    the relevant facts, Dr. Gerson reported that "[t]he temporal
    relationship and the nature of her complaints lead
    me to conclude that with reasonable medical certainty, the
    cause of Dr. Kannankeril's Central Nervous System
    manifestations of toxicity is exposure to Dursban in 1989 to
    1990." App. at 51. Dr. Gerson's testimony is neither
    conjecture nor speculation. His opinion was clearly stated
    to a reasonable degree of medical certainty.
    _________________________________________________________________
    8. It is an acknowledged scientific fact that chlorpyrifos, the active
    ingredient in Dursban, is harmful to humans and can cause the very
    symptoms displayed by Dr. Kannankeril.
    12
    Whether the appellants' expert might have done a better
    job is not the test. We have stated that "it is an abuse of
    discretion to exclude testimony simply because the trial
    court does not deem the proposed expert to be the best
    qualified or because the proposed expert does not have the
    specialization that the court considers most appropriate."
    Holbrook, 80 F.3d at 782. If the expert meets liberal
    minimum qualifications, then the level of the expert's
    expertise goes to credibility and weight, not admissibility.
    See Paoli, 
    35 F.3d at 741
    . The Second Circuit addressed a
    similar issue and commented that the expert's alleged
    shortcomings were raised properly on cross-examination
    and went to the credibility, not the admissibility, of his
    testimony. McCullock, 
    61 F.3d 1038
    , 1043 (2d Cir. 1995).
    Consequently, we reject Terminix's suggestion that Dr.
    Gerson must be a specialist in Dursban to provide expert
    testimony on the causation of Dr. Kannankeril's injury.
    The Kannankerils' burden is only to provide an expert
    opinion that is relevant and reliable and that will assist the
    trier of fact. As we have repeated above, issues of credibility
    arise after the determination of admissibility. Credibility is
    for the jury. We conclude that, under the facts presented
    here, the district court erred in ruling that Dr. Gerson's
    expert testimony on causation was inadmissible.
    IV. CONCLUSION
    For the foregoing reasons, we hold that the district court
    erred as a matter of law in refusing to permit Dr. Gerson to
    testify as to his opinion of the causation of Dr.
    Kannankeril's illness. Accordingly, we will vacate that
    portion of the district court order which granted summary
    judgment against Dr. Mary Kannankeril, and we will
    remand this case for further proceedings consistent with
    this opinion.
    A True Copy:
    Teste:
    Clerk of the United States Court of Appeals
    for the Third Circuit
    13