Full opinion text
MEMORANDUM AND ORDER EISELE, Senior District Judge. Before the Court is the Pesticide Defendants’ Motion to Exclude Opinion Testimony of Plaintiffs’ Expert Witnesses; the Pesticide Defendants’ Motion for Summary Judgment; and the Plaintiffs’ Daubert Mo-ti°n and their response to all of the above, This Order will address the admissibility of plaintiffs’ expert testimony as it relates to the pesticide known as Dursban LO. The Pesticide Defendants seek to strike the causation testimony of the following plaintiffs’ expert witnesses: Morris Cranmer, Gunnar Heuser, Robert Laird, Jesse Bidanset, Janette Sherman, and Jane Miers. The Court will attempt to evaluate each of said experts and his or her contested testimony but only to the extent necessary to determine if their proffered testimony meets the standards set forth in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993), which focuses primarily on Federal Rules of Evidence 702 and 703. From the pre-September 12, 1996, submissions of the plaintiffs the Court has prepared a rough summary of the key testimony expected of these witnesses, which summary is attached hereto as Appendix A. The Court will separately deal with the “live” testimony of Dr. Sherman at the September 12, 1996, hearing. When a serious challenge is made to the admissibility of expert scientific evidence, the Court will ordinarily hold an in limine hearing or conference to consider the disputed evidence and then make the findings required by Daubert. Here, the Pesticide Defendants, through their filings and submissions, have raised such a challenge to plaintiffs’ expert causation evidence. Therefore, an on-the-record conference and argument was held on March 27, 1996. A second hearing was held on September 12, 1996, at which the plaintiffs put on the testimony of Dr. Sherman. After the testimony of Dr. Sherman, further oral arguments were made by the parties. This Memorandum and Order will deal with the issues raised by the pending motions and by the arguments made by the parties orally and in their written submissions. On May 16, 1996, this Court entered a written order granting separate defendant Steam Services’ Motion to Strike Plaintiffs’ Expert Witnesses and for Summary judgment. That order reviewed at some length the Daubert decision and its progeny. Much of what was said there will be repeated here (with very few changes) so that this opinion can better stand on its own. I. FACTS According to the plaintiffs’ submissions, Mrs. Maria Smits was employed at the Eagle Bank in Sherwood, Arkansas, during the early months of 1991. The date of conception of Ashley Smits was on or about January 16, 1991. Ashley was born on September 20, 1991, with multiple birth defects. On October 4, 1993, Maria Smits and her husband, William Smits, had a son who is perfectly normal. On February 5, 1991, Maria Smits first learned that she was pregnant. On February 6, 1991, the Adams Pest Control Company made a “crack and crevice” application of a 0.5% solution of Dursban LO in water around the baseboards in the interior of the Eagle Bank Building. This work began around 4:00 p.m. Mrs. Smits states that she worked there that day until 6:00 p.m. On February 11, 1991, there was a small electrical fire at the Bank. On the same day (after the fire was put out) Steam Services applied Firefog 404, a reorderant. Mrs. Smits worked that day from 12:00 noon until 6:30 p.m. and, indeed, continued to work at the Eagle Bank in Sherwood until the first part of April, 1991, a period of approximately two months. Plaintiffs allege that Mrs. Smits was continuously exposed to Firefog and Dursban while she worked at the bank since those chemical agents remained in the Bank and continued to be volatilized into the air and inhaled by her and that she was also exposed to the chemicals through skin exposure since those chemicals were left on the various surfaces in the Bank. Plaintiffs state that Maria Smits became nauseated after her exposure to Dursban LO on February 6, 1991, and that she vomited that night. It is also claimed that after exposure to the Firefog 404 Mrs. Smits could taste the chemicals (a sweet taste) in her mouth and that she could smell the odor of the chemicals. Plaintiffs allege that Mrs. Maria Smits was a young and healthy, woman, well-nourished, a non-smoker, a non-user of alcohol and that she did not take any known teratogenic drugs during her pregnancy. Plaintiffs also allege that Mrs. Smits had no family history of birth defects and had no detectible genetic defects and that Ashley’s blood lead was normal at birth. Plaintiffs allege that Maria Smits was exposed to Dursban LO during a critical time in Ashley’s development — that is, during the period of time when her nervous and other developing systems were most sensitive to such chemical agents. It is important, in the evaluation of plaintiffs’ expert testimony, to have some knowledge of Dursban’s ingredients. Although defendants’ experts do not fully agree, the Court will accept the plaintiffs’ expert’s description of the Dursban Ingredients: * Chlorpyrifos (NOTE: The formula and ingredients are filed with this opinion Under Seal because of defendants’ assertion that same constitutes a trade secret or confidential proprietary information. The footnotes to same are not deleted.) II. STANDARD OF ADMISSIBILITY We start with Justice Blackmun’s opinion in Daubert. After concluding that the Frye Rule (“that austere standard”) should not be applied in federal trials, Daubert, 509 U.S. at 589, 113 S.Ct. at 2794, Justice Blackmun went on to discuss the proper test for admissibility of scientific evidence. He pointed out that Rule 702 nowhere refers to the “general acceptance” test of Frye. He then explained as follows: 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; 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). It is important also to consider Justice Blackmun’s footnote to this observation: We note that scientists typically distinguish between “validity” (does the principle support what it purports to show?) and “reliability” (does application of the principle produce consistent results?). ****** ... our reference here is to evidentiary reliability — that is, trustworthiness. ****** In a ease involving scientific evidence, evidentiary reliability will be based upon scientific validity. Id., at n. 9. The majority opinion then goes on to state 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.” * Hs * * * * Rule 702’s “helpfulness” standard requires a valid scientific connection to the pertinent inquiry as a precondition to admissibility. That these requirements are embodied in Rule 702 is not surprising. Unlike an ordinary witness, see Rule 701, an expert is permitted wide latitude to offer opinions, including those that are not based on firsthand knowledge or observation. See Rules 702 and 703. Presumably, this relaxation of the usual requirement of firsthand knowledge — a rule which represents “a ‘most pervasive manifestation’ of the common law insistence upon ‘the most reliable sources of information,’” Advisory Committee’s Notes on Fed.Rule Evid. 602 (citation omitted) — is premised on an assumption that the expert’s opinion will have a reliable basis in the knowledge and experience of his discipline. Dcmbert, 509 U.S. at 591-92, 113 S.Ct. at 2796. With this doctrinal background in mind, Justice Blackmun then provides the trial judge with practical instructions on how to proceed when expert scientific testimony is challenged: Faced with a proffer of expert scientific testimony, then,, the trial judge must determine at the outset, pursuant to Rule 104(a), whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue. This entails 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. We are confident that federal judges possess the capacity to undertake this review. Many factors will bear on the inquiry, and we do not presume to set out a definitive checklist or test. But some general observations are appropriate. Ordinarily, a key question to be answered in determining whether a theory or technique is scientific knowledge that will assist the trier to fact will be whether it can be (and has been) tested. “Scientific methodology today is based on generating hypotheses and testing them to see if they can be falsified; indeed, this methodology is what distinguishes science from other fields of human inquiry.” Green at 645. See also C. Hempel, Philosophy of Natural Science 49 (1966) (“[T]he statements constituting a scientific explanation must be capable of empirical test”); K. Popper, Conjectures and Refutations: The Growth of Scientific Knowledge 37 (5th ed. 1989) (“[T]he criterion of the scientific status of a theory is its falsifiability, or refutability, or testability”). Another pertinent consideration is whether the theory or technique has been subjected to peer review and publication. Publication (which is but one element of peer review) is not a sine qua non of admissibility; it does not necessarily correlate with reliability, see S. Jasanoff, The Fifth Branch: Science Advisors as Policymakers 61-76 (1990), and in some instances well-grounded but innovative theories will not. have been published, see Horrobin, The Philosophical Basis of Peer Review and the Suppression of Innovation, 263 J.Am. Med.Assn. 1438 (1990). Some propositions, moreover, are too particular, too new, or of too limited interest to be published. But submission to the scrutiny of the scientific community is a component of “good science,” in part because it increases the likelihood that substantive flaws in methodology will be detected. See J. Ziman, Reliable Knowledge: An Exploration of the Grounds of Belief in Science 130-133 (1978); Reiman and Angelí, How Good Is Peer Review?, 321 New Eng. J.Med. 827 (1989). The fact of publication (or lack thereof) in a peer-reviewed journal thus will be a relevant, though not dispositive, consideration in assessing the scientific validity of a particular technique or methodology on which an opinion is premised. Additionally, in the case of a particular scientific technique, the court ordinarily should consider the known or potential rate of error, see, e.g., United States v. Smith, 869 F.2d 348, 353-354 (7th Cir.1989) (surveying studies of the error rate of spectrographic voice identification technique), and the existence and maintenance of standards controlling the technique’s operation. See United States v. Williams, 583 F.2d 1194, 1198 (2d Cir.1978) (noting professional organization’s standard governing spectrographic analysis), cert. denied, 439 U.S. 1117, 99 S.Ct. 1025, 59 L.Ed.2d 77 (1979). Finally, “general acceptance” can yet have a bearing on the inquiry. A “reliability assessment does not require, although it does permit, explicit identification of a relevant scientific community and an express determination of a particular degree of acceptance within that community.” United States v. Downing, 753 F.2d [1224] at 1238 [(3d Cir.1985)] See also 3 Weinstein & Berger ¶ 702[03], pp. 702-41 to 702-42. Widespread acceptance can be an important factor, in ruling particular evidence admissible, and “a known technique that has been able to attract only minimal support within the community,” Downing, supra, at 1238, may properly be viewed with skepticism. The inquiry envisioned by Rule 702 is, we emphasize, a flexible one. Its overarching subject is the scientific validity — and thus the evidentiary relevance and reliability— of the principles that underlie a proposed submission. The focus, of course, must be solely on principles and methodology, not on the conclusions that they generate. Daubert, 509 U.S. at 592-95, 113 S.Ct. at 2796-97. The Daubert opinion also instructs the trial judge to be mindful of the provisions of Rules 703, 706 and 403. Finally, the trial judge is admonished that if she or he con-eludes that a scintilla of evidence supporting a position is insufficient to allow a reasonable jury to conclude that the position is more likely than not true, the court remains free to direct a judgment, see Fed. Rule Civ. Proc. 50(a), and likewise to grant summary judgment, Fed. Rule Civ. Proc. 56. This is to remind us that scientific evidence may raise questions not only as to admissibility but also as to sufficiency. It is interesting to note that Justice Blackmun cites the case of Brock v. Merrell Dow Pharmaceuticals, Inc., 874 F.2d 307 (5th Cir.1989), modified, 884 F.2d 166 (5th Cir.1989), in support of this proposition. In summary, Justice Blackmun states that the rules of evidence (especially Rule 702), ... do assign to the trial judge the task of ensuring that an expert’s testimony both rests on a reliable foundation and is relevant to the task at hand. Pertinent evidence based on scientifically valid principles will satisfy those demands. Daubert, 509 U.S. at 597, 113 S.Ct. at 2799. Daubert holds that admissibility under Rule 702 is governed by Rule 104(a), which requires the judge to conduct “preliminary fact-finding, to make a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and whether that reasoning or methodology properly can be applied to the facts in issue.” Id., at 592-93, 113 S.Ct. at 2796. Thus, before admitting scientific evidence, the Court must, inter alia, determine whether the theory advanced by the expert has been subjected to the “scientific method.” Id. at 590, 593-95, 113 S.Ct. at 2795, 2797. And the focus of this inquiry must be on “principles and methodology, not on the conelusions that they generate.” Daubert, at 595, 113 S.Ct. at 2797. “Scientific validity” and “fit” inquiries may overlap. For example, if published theories and studies purport to prove A, yet from those studies an expert concludes B, it may be that the expert’s reasoning process is not valid, although the studies or theories she relies upon are. In sum, there may be a lack of “fit” between the studies and theories and the conclusion the expert draws from them. Each step of the experts’ methodology must be scientifically valid. See In re Paoli R.R. Yard PCB Litigation, 35 F.3d 717, 745 (3d Cir.1994). For example, in a situation where an expert relies on studies of the effects of animal exposure to a particular chemical to prove similar effects in humans, “[cjourts must assess the scientific validity of the hypothesis proffered to justify such an extrapolation.” Developments in the Law—Confronting the New Challenges of Scientific Evidence, 108 Harv. L. Rev. 1481, 1536 (1995). When Daubert was remanded back to the Ninth Circuit by the Supreme Court, it became necessary for the judges of the Ninth Circuit to apply the new standard for the admissibility of expert scientific testimony. Circuit Judge Kozinski wrote the opinion for the panel and introduced his analysis with the following background: Two minors brought suit against Merrell Dow Pharmaceuticals, claiming they suffered limb reduction birth defects because their mothers had taken Bendectin, a drug prescribed for morning sickness to about 17.5 million pregnant women in the United States between 1957 and 1982. See Rsp’t’s Br. on Writ of Cert. at 2; Turpin v. Merrell Dow Pharmaceuticals, Inc., 959 F.2d 1349, 1350 (6th Cir.1992). This appeal deals with an evidentiary question: whether certain expert scientific testimony is admissible to prove that Bendectin caused the plaintiffs’ birth defects. For the most part, we don’t know how birth defects come about. We do know they occur in 2-3% of births, whether or not the expectant mother has taken Bendectin. See Jose F. Cordero & Godfrey P. Oakley, Jr., Drug Exposure During Pregnancy: Some Epidemiologic Considerations, 26 Clinical Obstetrics & Gynecology 418, 424-25 (June 1983). Limb defects are even rarer, occurring in fewer than one birth out of every 1000. Turpin, 959 F.2d at 1353. But scientists simply do not know how teratogens (chemicals known to cause limb reduction defects) do their damage: They cannot reconstruct the biological chain of events that leads from an expectant mother’s ingestion of a teratogenic substance to the stunted development of a baby’s limbs. Nor do they know what it is about teratogens that causes them to have this effect. No doubt, someday we will have this knowledge, and then we will be able to tell precisely whether and how Bendectin (or any other suspected teratogen) interferes with limb development; in the current state of scientific knowledge, however, we are ignorant. Not knowing the mechanism whereby a particular agent causes a particular effect is not always fatal to a plaintiffs claim. Causation can be proved even when we don’t know precisely how the damage occurred, if there is sufficiently compelling proof that the agent must have caused the damage somehow. One method of proving causation in these circumstances is to use statistical evidence. If 50 people who eat at a restaurant one evening come down with food poisoning during the night, we can infer that the restaurant’s food probably contained something unwholesome, even if none of the dishes is available for analysis. This inference is based on the fact that, in our health-conscious society, it is highly unlikely that 50 people who have nothing in common except that they ate at the same restaurant would get food poisoning from independent sources. It is by such means that plaintiffs here seek to establish that Bendectin is responsible for their injuries. They rely on the testimony of three groups of scientific experts. One group proposes to testify that there is a statistical link between the ingestion of Bendectin during pregnancy and limb reduction defects. These experts have not themselves conducted epidemiological (human statistical) studies on the effects of Bendectin; rather, they have reanalyzed studies published by other scientists, none of whom reported a statistical association between Bendectin and birth defects. Other experts proffered by plaintiffs propose to testify that Bendectin causes limb reduction defects in humans because it causes such defects in laboratory animals. A third group of experts sees a link between Bendectin and birth defects because Bendectin has a chemical structure that is similar to other drugs suspected of causing birth defects. The opinions proffered by plaintiffs’ experts do not, to understate the point, reflect the consensus within the scientific community. The FDA — an agency not known for its promiscuity in approving drugs — continues to approve Bendectin for use by pregnant women because “available data do not demonstrate an association between birth defects and Bendectin.” U.S. Department of Health and Human Services News, No. P. 80-45 (Oct. 7,1980). Every published study here and abroad— and there have been many — concludes that Bendectin is not a teratogen. Turpin, 959 F.2d at 1353-56. In fact, apart from the small but determined group of scientists testifying on behalf of the Bendectin plaintiffs in this and many other cases, there doesn’t appear to be a single scientist who has concluded that Bendectin causes limb reduction defects. Daubert v. Merrell Dow Pharmaceuticals, Inc., 43 F.3d 1311, 1313-1314 (9th Cir.1995). After reexamining the challenged expert opinions under the Supreme Court’s new standards, the Ninth Circuit concluded that the plaintiffs had not met that standard. In the context of the Smits case, the plaintiffs must establish by a preponderance of the evidence that their expert testimony meets the Daubert standards of scientific reliability. This issue is different from the one that will be submitted to the jury if the plaintiffs’ evidence satisfies those standards. In the latter case, the plaintiffs will have to establish by a preponderance of the evidence to the jury’s satisfaction that Dursban LO caused the birth defects sustained by Ashley Smits. By contrast, the trial judge, when passing upon the admissibility of testimony under Daubert, does not deal directly with the causation issue. Rather the judge asks whether it is more likely true than not true that plaintiffs’ expert testimony meets the Daubert standard of admissibility, i.e. evidentiary reliability based upon scientific validity. Justice Blaekmun concluded his opinion in Daubert by pointing out that the law’s interest in ascertaining the truth differs from that in the scientific community. “Scientific conclusions are subject to perpetual revisions” whereas the need to “resolve disputes fairly and quickly” in a courtroom “inevitably on occasion will prevent the jury from learning from authentic insight and innovation.” The law simply cannot wait upon the results of future scientific investigation and research. Cases pending in our courts must be resolved on the basis of scientific knowledge currently available. III. DURSBAN LO — DEFENDANTS’ CHALLENGE The Pesticide Defendants move the Court to exclude from evidence plaintiffs’ expert opinion testimony on general and specific causation. The ultimate opinions of these plaintiffs’ experts are (1) that Dursban LO is capable of causing birth defects in humans (general causation) and (2) that Maria Smits’ exposure to Dursban during her pregnancy caused Ashley Smits’ birth defects (specific causation). Of course, adequate satisfactory proof of the latter proposition would also establish the former. The Pesticide Defendants make the following main points: 1. The Pesticide Defendants assert that none of the challenged experts has the “education, experience, or expertise in the fields of science dealing with determination of causes of birth defects (teratology and medical genetics) ... [and] they are not qualified to give expert opinions on this subject.” Pesticide Defendants’ Motion to Exclude, p. 2. 2. The Pesticide Defendants argue that plaintiffs’ experts have not done any independent research in an effort to determine if Dursban LO is capable of causing human birth defects. Indeed, the Pesticide Defendants assert that four of plaintiffs’ six experts have not, heretofore, been involved in the field of birth defects, while the other two have done no research in such field independent of litigation. 3. The methodologies used by plaintiffs’ experts are not reliable and are not used by experts in the relevant scientific field. The Pesticide Defendants argue that the methodology that should be utilized is that which teratologists use to determine whether a substance is a teratogen. 4. Dr. Sherman’s published case report of four birth defect cases allegedly due to Dursban is unreliable because 1. case reports are not relied on by the scientific community to establish general causation; 2. the article stems from, and arises out of, litigation; 3. Dr. Sherman was plaintiffs’ expert in all three cases (one case involved brother/sister); 4. the article does not reveal the litigation connection or her personal financial interest in such litigation; 5. the children’s defects were diagnosed as being genetic in origin; 6. the defects in two cases have been diagnosed as COFS/Micro syndrome and one case has been identified as CHARGE association; 7. the fourth case is distinguishable because exposure occurred in the second trimester; and 8.seventy to eighty percent of all birth defect cases are due to unknown causes. IV. PLAINTIFFS’RESPONSE Plaintiffs assert that they have presented reliable and relevant evidence. They point to evidence which they assert demonstrates that Dursban LO and/or its components and metabolites are known teratogens. They rely, inter alia, on the Hanley study which reported that Administration of Triehloropyridinol, to pregnant rabbits was considered teratogenic at a dose level of 250 mg/kg/day, a level which also depressed maternal weight gain. Indications of a teratogenic potential were also observed at 100 mg/kg/day in the absence of any measured maternal toxicity. No adverse effects were observed in either maternal or fetal rabbits at 25 mg/kg/day. They also cite a letter from Dow to the EPA dated July 24, 1992, which summarized the Hanley study as follows: the incidence of central nervous system (CNS) anomalies (hydrocephaly and severely dilated cerebral ventricles) has increased in both the 100 and 250 mg/kg day base groups. And the plaintiffs point to the MSDS for tricholorpyridinol (“TCP”), the active ingredient of Dursban LO, which states as follows: Teratology (Birth Defects): Has been reported to cause birth defects in laboratory animals at doses non-toxic to the mother. The plaintiffs argue: The Court should know that Dr. Chris Cunniff, former geneticist at Arkansas Children’s Hospital, now at the University of Arizona Medical Center, told Dr. Miers, a pediatrician, that he did not know what caused Ashley’s constellation of defects but that he did not think it was a genetic disorder. Also Dr. Barbara Crandall, geneticist at the U.C.L.A. Medical Center, ruled out several syndromes that she considered, including: Craniosynostosis, Antley-Bixler syndrome, Crouzon syndrome, and she also considered an association of defects called CHARGE (which is not a syndrome at all). Her final diagnosis was that Ashley’s symptoms are suggestive of CHARGE association b.ut that was not a definite diagnosis, and she went on further, and stated that she could not rule out a teratogen as the etiologie cause of Ashley’s birth defects. Only Defense witness, Dr. John Graham, geneticist at the Cedars-Sinai Medical Center in Los Angeles, California, a former witness for the Dow defendants in another Dursban case (Burke), stated in his report that Ashley’s problems appear to be CHARGE association, a pattern of birth defects which is thought to be due to a fresh dominant genetic mutation, a limited transmission to offspring due to the associated hypogonadotropie hypogonadis. These statements' by Dr. Graham are speculative and should carry no weight in this court’s decision regarding the Defendants’ Motions for Summary Judgement. Plaintiffs emphasize Dr. Sherman’s “peer reviewed” articles: Chlorpyrifos (Dursban)—Associated Birth Defects: A Proposed Syndrome, Report of Four Cases, and Discussion of the Toxicology, International Journal of Occupational Medicine and Toxicology, Vol.4, No. 4 (1995); and Chlorpyrifos (Dursban)—Associated Birth Defects: Report of Four Cases, Archives of Environmental Health, Vol 51, No. 1, (Jan./Feb. 1996). Plaintiffs also note that, since the publication of those articles, Dr. Sherman has “discovered two more children who were exposed to Dursban LO which resulted in birth defects.” Plaintiffs’ Supplement, p. 22-23. V. SUBSEQUENT PROCEEDINGS As stated above, on March 29, 1996, the Court held an in-court conference on the Daubert motions and heard argument from all parties. In addition, the Court was the beneficiary of lengthy and detailed pre-hearing and post-hearing submissions from all parties addressing the Daubert issue. On May 16, 1996, the Court issued an Order granting Steam Services’ motion to strike the proffered causation testimony of plaintiffs’ expert witnesses. And,. because plaintiffs then had no evidence which could establish causation with respect to the chemical agent Firefog 404, Steam Services’ motion for summary judgment was also granted. After summary judgment was entered in favor of Steam Services, the Court scheduled a further hearing and further argument on the Daubert issues for September 12, 1996. In anticipation thereof the Court wrote three letters to the parties in an attempt to give some focus and guidance to that proceeding. Two of those letters were sent on August 14 and the third on August 16, 1996. They are attached hereto as Appendices B, C and D to this opinion. ■ The plaintiffs requested that they be permitted to bring the live testimony of Dr. Sherman before the Court at the hearing. At a telephone conference held on September 5,1996, the Court agreed to permit the plaintiffs to put on the testimony of Dr. Sherman. On that same day, the Court mailed to the parties a copy of its “Notes Regarding Major Studies” dealing with the Muto, Hanley and Deacon studies. Those notes are attached hereto as Appendix E. More importantly the Court sent to the parties its “Notes and Comments” setting forth its tentative views on many of the important issues. Those “Notes and Comments” are attached hereto as Appendix F and are incorporated herein in their entirety by reference. It will be seen therefrom that the Court had concluded from the record, prior to the September 12, 1996, hearing, that the defendants were correct in stating that there is a consensus in the relevant scientific community (composed of teratologists and medical geneticists) concerning the protocol and methodology that must be followed in order to establish a particular chemical agent as a human teratogen. Through the use of that methodology and the reasoning it adopts, some forty chemical agents have been established as human teratogens. Dursban LO is not one of them. The Court stated that the defendants had satisfied it that they are correct on their general causation arguments. But the Court was not ready to agree at that time that that conclusion alone was enough to require it to grant the defendant’s Daubert motion by excluding all of the plaintiffs’ causation evidence. The Court stated its view that in some cases a plaintiffs proof would be sufficient to go to a jury without having first established the suspect chemical agent as a human teratogen by the use of the accepted protocol. The Court concluded its “Notes and Comments” as follows: From my own examination of Dr. Sherman’s articles, from the critiques thereof by Drs. Graham and Johnson, and from the written and oral arguments of defendants’ counsel, I have come to the tentative conclusion that Dr. Sherman’s analysis and causation opinions are not derived from any accepted scientific methodology (i.e., are not grounded in the methods and procedures of science), are not scientifically valid and, ergo, do not possess the evidentiary reliability required by Daubert. This is not to say that Dursban LO is not a teratogen or that it did not cause Ashley’s birth defects. It is to say that Dr. Sherman’s submissions and opinions are not derived from scientific methods and are nothing more than an invitation to the jury to speculate (rather than a reliable basis upon which the jury could find that it is more likely true than not true that Dursban LO caused the birth defects suffered by Ashley.) Therefore the views and opinions expressed would not assist the trier of fact to determine the cause of those defects. My tentative view is that Dr. Sherman’s case studies do nothing more scientifically than to suggest a causal relation. That hypothesis has not to date been legitimized by further research and studies. In sum, there have been no epidemiological studies, no repeatable dose-response animal studies, no other studies which would connect Dr. Sherman’s speculative hypothesis to a scientific proposition having acceptance in at least a segment of the pertinent scientific community. (Note: Dr. Bidanset’s in vitro and in vivo studies will be discussed later.) The defendants state that Dr. Sherman’s article relies, inter alia, on the reasoning that the exposure of each of the mothers to Dursban occurred in the first trimester of pregnancy. In her deposition at pages 689-691 she affirms that her theory requires exposure to the chemical agent during the first trimester which she identifies as “this critical point in development when these key structures are formed ...” Defendants then point out that Sherman’s own report in the case of child # 2 (Daniel Gillespie) and the medical records for that pregnancy confirm that the application of Dursban occurred after the first trimester. The Court will ask the plaintiffs at the September 12 conference if they agree or disagree that child # 2 should be eliminated when evaluating Dr. Sherman’s article and, if so, what effect that might have on the remainder of that study. The defendants then state that the patterns of symptoms described by Dr. Sherman in her article are not really present and that the children do not in fact show any concordance of symptoms. Then defendants state: Moreover, it is not scientifically acceptable to collectively analyze children with multiple anomalies and recognized birth defect syndromes as Sherman has done because by definition the children have patterns of defects which can only be combined if the defects have the same pathogenetic basis. (Graham Decl. ¶ 23). That is not present here. To evaluate the legitimacy of Dr. Sherman’s statistical analysis it is necessary for the Court to resolve the issue raised by the defendants’ response. Did the children suffer from the same complex or pattern of defects? To give further guidance to the parties with regard to the issues of concern, the Court stated in its August 14, 1996, letter: The first issue relates to exposure and dosage both of Mrs. Smits and Ashley while in útero. After plaintiffs detail all of the evidence in the record on these issues and argue its medical and scientific adequacy, defendants’ attorneys will respond. The second phase of the argument will relate to specific causation. Here again plaintiffs’ attorneys will open and then defendants’ attorneys will respond. VI. IMPORTANT ADDITIONAL LEGAL AUTHORITY After hearing the testimony of Dr. Sherman at the September 12, 1996, proceeding, the Court quoted at some length from the article “Scientific Evidence After Daubert” by David M. Levy, which appeared in the fall 1995 edition of the ABA journal, Litigation. It then brought the parties’ attention to the case of Wright v. Willamette Industries, Inc., 91 F.3d 1105 (8th Cir.1996) which was decided by a panel of the Eighth Circuit Court of Appeals on August 2, 1996. The Court, stating that this was an extremely important case, noted that an application for rehearing and a suggestion for rehearing en banc had been made and that, therefore, the final word on Wright was not in. The Wright case is so important that it should be quoted almost in its entirety. Judge Morris Sheppard Arnold wrote the opinion for the majority of the panel, and Judge Gerald Heaney dissented. The Court will first quote from Judge Arnold’s opinion as follows: The most significant issue in this toxic tort ease is whether members of the Wright family, plaintiffs who prevailed at trial, produced sufficient evidence to submit their negligence claim to the jury. We find that they did not and therefore reverse the judgment of the district court. Appellant Willamette Industries owns a fiberboard manufacturing plant near the town of Malvern in western Arkansas. Willamette takes pine wood shavings and pulp and refines them into a fiber, which is then dried. A resin of urea formaldehyde is mixed with the fiber just prior to drying. It is undisputed that the plant emits particulate matter, part of which has been treated with formaldehyde, into the air. The Wrights live a short distance from the plant and claim to have suffered from a number of afflictions (e.g., headaches, sore throats, watery eyes, running noses, dizziness, and shortness of breath) which they blame on the emissions from the plant. The Wrights brought suit on a variety of theories and prevailed on their negligence claim. The jury awarded the five plaintiffs a total of $226,250.00 in compensatory damages for their personal injuries. Willamette made a number of post-verdict motions for judgment as a matter of law, which the district court denied. On appeal, Willamette, emphasizes, among other things, that the Wrights failed to make out a submissible case on the issue of proximate cause. We review a district court’s denial of a motion for judgment as a matter of law by applying the same standard that the district court applied originally. Sherbert v. Alcan Aluminum Corp., 66 F.3d 965, 967 (8th Cir.1995). Willamette’s motion for judgment as a matter of law should not be granted unless all the evidence points its way and is susceptible of no reasonable inferences sustaining the Wrights’ position (citing cases). The Wrights, of course, had the burden of proving proximate cause in order to recover under their negligence theory (citing cases). Proximate cause in Arkansas is defined as a “ ‘Cause which, in a natural and continuous sequence, produces damage and without which the damage would not have occurred.’” Rogers v. Armstrong World Indus., Inc., 744 F.Supp. 901, 904 (E.D.Ark.1990) (quoting Ark.Model Jury Instr. Civil 3d ed. 501). Willamette contends, among other things, that in order to shift the costs of their injuries to Willamette the Wrights had to demonstrate actual exposure to a toxic substance emitted from Willamette’s plant at levels that are known to produce harms like the ones of which the Wrights complain. Willamette’s emphasis on exposure levels is a reasonable one that is reflected in a number of recent toxic tort eases (citing cases). We agree with Willamette that a plaintiff in a toxic tort ease must prove the levels of exposure that are hazardous to human beings generally as well as the plaintiffs actual level of exposure to the defendant’s toxic substance before he or she may recover. The Wrights cite two Arkansas cases, Worthington v. Roberts, 304 Ark. 551, 803 S.W.2d 906 (1991), and Southwestern Bell Telephone Co. v. Smith, 220 Ark. 223, 247 S.W.2d 16 (1952), for the proposition that Arkansas does not require proof of the level of exposure in toxic tort cases. In Smith, a telephone company sprayed vegetation under its telephone lines, after which Mr. Smith’s cows ate the vegetation and died; and in Roberts, pesticides drifted in a strong wind onto Mr. Roberts’s property after a crop duster sprayed nearby fields, following which Mr. Roberts’s trees and vegetation appeared to have been damaged. We believe that plaintiffs’ reliance on these cases is misplaced. The reports of these cases do not reveal whether the plaintiff offered any proof concerning what levels of the relevant chemical might be expected to produce appreciable harm to animals or plants. The argument that defendants make in this case was simply not advanced in these previous Arkansas eases, and they are therefore of no precedential value on the precise question which concerns us here. A legislature might well altogether outlaw a substance on the ground that it is known to involve a risk of appreciable harm to human beings, without having precise data on the question of how much harm, or what kind of harm, some specific amount of that substance might reasonably be expected to cause to some particular kinds of persons or even to an average or an ordinary person. Such legislation would presumably, as an ordinary matter, survive judicial scrutiny as a rational exercise of the police power. (Citing case)____ * * X * * * Whatever may be the considerations that ought to guide a legislature in its determination of what the general good requires, courts and juries in deciding eases traditionally make more particularized inquiries into matters of cause and effect. Actions in tort for damages focus on the question of whether to transfer money from one individual to another, and under common-law principles (like the one that Arkansas law recognizes) that transfer can take place only if one individual proves, among other things, that it is more likely than not that another individual has caused him or her harm. It is therefore not enough for a plaintiff to show that a certain chemical agent sometimes causes the kind of harm that he or she is he complaining of. At a minimum, we think that there must be evidence from which the fact finder can conclude that the plaintiff was exposed to levels of that agent that are known to cause the kind of harm that the plaintiff claims to have suffered. See Abuan v. General Elec. Co., 3 F.3d [329] at 333 [(9th Cir.1993)]. We do not require a mathematically precise table equating levels of exposure with levels of harm, but there must be evidence from which a reasonable person could conclude that a defendant’s emission has probably caused a particular plaintiff the kind of harm of which he or she complaints before there can be a recovery. In this case, while the Wrights proved that they were exposed to defendant’s emissions and that wood fibers from defendant’s plant were in their house, their sputum, and their 'urine, they failed to produce evidence that they were exposed to a hazardous level of formaldehyde from the fibers emanating from Willamette’s plant. Their experts’ information on this subject was simply insufficient. Dr. Fred Fowler, an industrial hygienist, and Dr. Jimmie Valentine, a pharmacologist, did offer testimony about the levels of gaseous formaldehyde that might be expected to cause symptoms like the ones that plaintiffs claim to have experienced. But the Wrights do not claim to have been injured from breathing gaseous formaldehyde, and they make no reference to any studies that reveal the levels of exposure to wood fibers impregnated with formaldehyde that are likely to produce adverse consequences. It is true that Dr. Frank Peretti, after a great deal of prodding, testified that the Wrights’ complaints were more probably than not related to. exposure to formaldehyde, but that opinion was not based on any knowledge about what amounts of wood fibers impregnated with formaldehyde involve an appreciable risk of harm to human beings who breathe them. The trial court should therefore have excluded Dr. Paired’s testimony, as Willamette requested it to do, because it was not based on scientific knowledge. See Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 589-91, 113 S.Ct. 2786, 2794-96, 125 L.Ed.2d 469 (1993); Fed.R.Evid. 702; Federal Judicial Center Reference Manual on Scientific Evidence 47-48 (1994). Dr. Paired’s testimony regarding the probable cause of the Wrights’ claimed injuries was simply speculation. The jury could therefore only have speculated about whether the amount of formaldehyde from Willamette’s plant to which each plaintiff was exposed was sufficient to cause their injuries or, indeed, any injuries at all ... Without proving hazardous levels of exposure to Willamette’s formaldehyde, the Wrights failed to carry their burden of proof at trial on the issue of causation because the evidence failed to support a reasonable inference in favor of the jury’s implicit finding against Willamette on the causation issue. Judge Heaney, in his dissenting opinion, disagrees with our characterization of this case as being about money, and expresses the view that this “fails to acknowledge the important human elements regarding the injuries at issue.” But lawsuits, unless they seek only a declaratory judgment, are always either about money or some form of specific relief. Those are the only kinds of relief that a court can give and in this case all the plaintiffs asked for was money. Our characterization of the case is therefore the plaintiffs’ characterization of it. Money, moreover, is not properly to be contrasted with human or humane concerns. To the contrary, the reason that we compensate people (that is, transfer money from defendants to plaintiffs) is because rights that are grounded in considerations of humanity have been violated. We believe that it is humane to monetize welfare losses associated with grief, pain and suffering, humiliation, mental anguish, and other intangible injuries so that we can make plaintiffs whole. What we do not do, again for reasons grounded in humanity, is force a defendant to compensate a plaintiff if the plaintiff does not show that the defendant has probably done something to him. For the foregoing reasons, we reverse the judgment of the district court. In his dissent Judge Heaney states: It is undisputed that the Willamette plant emits minute wood fibers laced with formaldehyde. It is also undisputed that because Willamette failed to install equipment that would have significantly lowered the emissions, the levels of formaldehyde emitted from the plant exceeded levels permitted by industry and state standards. The Wright family lives within three-quarters of a mile of the plant. There is uneontradicted evidence that emissions from the plant fell like “snow” on the Wrights’ property to the extent that overnight emissions could be seen on cars. Fibers from the plant were also found in the Wrights’ air conditioner. The Wright family was examined by physicians and significant levels of toxic emissions from the plant were found in their sputum and urine. The Wright family suffered from headaches, sore throats, watery eyes, runny noses, dizziness and shortness of breath which the treating physician testified were more probably than not related to their exposure to the plant emissions. ‡ % Jj; * I do not disagree with the majority’s statement that there must be evidence from which the jury could find that the Wrights were exposed to levels of formaldehyde that are known to cause the harm that the Wright family suffered. In fact, however, the required evidence was produced. The State of Arkansas has determined that no plant shall emit formaldehyde because such emissions are dangerous to the health of persons who ingest them. Willamette failed to install available equipment to control the discharge of this particulate matter in either the solid or gaseous form. The formaldehyde emissions found their way to the Wrights’ property. They were found in the family’s air conditioner, and more importantly, in the family’s sputum and urine. Competent medical testimony was presented that stated that it was more probable than not that their illness was caused by the formaldehyde. Thus, the circle was complete and proximate cause established. Dr. Peretti may or may not have been prodded to relate the Wrights’ illnesses to formaldehyde, but he did; and the jury could have rejected his testimony if it did not believe him. The Court has learned that the plaintiffs application for rehearing and suggestion of rehearing en banc was denied on September 19, 1996. Therefore, Wright is the latest Eighth Circuit decision in this developing area of the law. Wright is useful here also because it reminds us of the Arkansas law on proximate cause. See also Southern Company, Inc. v. Graham, 271 Ark. 223, 607 S.W.2d 677, 679 (Ark.1980) (possibility, conjecture or guess not enough). There are other cases that deal quite directly "with the issues before the Court. The Court will quote at length from one of them, the case of Cavallo v. Star Enterprise, 892 F.Supp. 756 (E.D.Va.1995), because of its startling relevance to this case. There Judge Ellis discusses eases dealing with the “fit” requirement, the dose-response relationship, and the limits upon extrapolations from known data: The Third Circuit addressed this problem in In re Paoli R.R. Yard PCB Litigation, 35 F.3d 717 (3d Cir.1994), cert. denied, 513 U.S. 1190, 115 S.Ct. 1253, 131 L.Ed.2d 134 (1995). There, residents housed near a railcar maintenance facility that had used polychlorinated biphenyls (commonly referred to as PCBs) in its business activities for many years claimed that their continued exposure to the PCBs had caused a variety of illnesses. In reviewing the Daubert principles, the Third Circuit panel noted that the scientific knowledge requirement, which mandates that the expert’s conclusions be based on “good grounds,” applies to each step of the expert’s analysis. Paoli R.R., 35 F.3d at 745. Thus, the panel emphasized that “any step that renders the analysis unreliable under the Daubert factors renders the expert’s testimony inadmissible. This is true whether the step completely changes a reliable methodology or merely misapplies that methodology.” Id. (emphasis in original). Similarly, the Paoli panel remarked that “the expert’s view that a particular conclusion ‘fits’ a particular case must itself constitute scientific knowledge — a challenge to ‘fit’ is very close to a challenge to the expert’s ultimate conclusion about the particular ease.” Id. at 746. Cf. Developments in the Law— Confronting the New Challenges of Scientific Evidence, 108 Harv. L.Rev. 1481, 1536 (1995) (stating that where expert relies on studies involving animal exposure to particular chemical to prove similar effect in humans, “[ejourts must assess the scientific validity of the hypothesis proffered to justify such an extrapolation”). This interrelationship between fit and scientific validity is illustrated by a case involving an alleged correlation between a pregnant woman’s use of Retin-A, a Vitamin A derivative acne medication, and her child’s birth defects. Chikovsky v. Ortho Pharmaceutical Corp., 832 F.Supp. 341 (S.D.Fla.1993). Although there were no published studies on the effects of Retin-A on fetal development, the plaintiff’s expert in Chikovsky concluded that the Retin-A absorbed by the mother had caused the child’s birth defects. He based this conclusion on studies showing a correlation between birth defects and high doses of Vitamin A and certain other Vitamin A derivatives. In holding that the expert’s opinion was not scientifically valid, the court cited the expert’s ignorance of the amounts of Retin-A absorbed by the plaintiff, noted the absence of any established dose-response relationship for Vitamin A and birth defects, and explicitly found that his “analogies to research concerning Vitamin A and other Vitamin A derivatives is [sic] wanting.” Id. at 346. Similarly, in Schmaltz v. Norfolk & Western Ry. Co., 878 F.Supp. 1119 (N.D.Ill.1995), the plaintiff claimed that his exposure to certain herbicides containing atrazine caused his chronic respiratory disease. Like the situation in Chikovsky, the plaintiffs expert could not cite any documented cases where exposure to these chemicals caused the alleged illness. Rather, he relied on studies where high doses of atrazine caused eye irritation in rabbits. In excluding the expert’s testimony under Daubert, the court observed that the record Fails to make clear why the incidence of eye irritation in rabbits exposed to high doses of atrazine could reasonably lead a doctor to conclude that an indirect exposure to atrazine could cause pulmonary or respiratory conditions in humans. “The analytical gap between the evidence presented and the inferences to be drawn on the ultimate issue ... is too wide” in the present case. Schmaltz, 878 F.Supp. at 1122 (quoting Conde v. Velsicol Chem. Corp., 24 F.3d 809, 814 (6th Cir.1994)). Thus, it is apparent that a determination regarding the scientific validity of a particular theory requires not only an examination of the trustworthiness of the tested principles on which the expert opinion rests, but also an analysis of the reliability of an expert’s application of the tested principles to the particular set of facts at issue. Id. at 762-763. And while specifically analyzing the proffered testimony of Dr. Monroe, a toxicologist, Judge Ellis observed as follows: As Dr. Rodricks explains, all chemicals can cause health problems' at some level or concentration of exposure, but they vary widely in the types of harm caused and in the levels of exposure required to trigger those harms. In addition, all chemicals have thresholds-of exposure that must be exceeded before the harms will occur, and these thresholds may be identified through scientific studies and literature. The task of the toxicologist, therefore, is to identify a dose-response relationship for a particular chemical (or chemical mixture) and illness and analyze the results to determine whether the duration and concentration of exposure in a given instance could have caused the alleged harms. (Rodricks Rpt. At 2-3). Id. at 764. Footnote 12 of the Cavallo opinion states as follows: Dr. Monroe was not aware of the concentration and duration of exposure in making his initial assessment. It is fairly clear from a review of the record that in many instances, Dr. Monroe did not follow the methodology to form his opinion but rather formed his opinion and then tried to conform it to the methodology. The following dialogue is illustrative: Q: And it’s your opinion that [a concentration of 61 mg/m] would be sufficient to cause sensitization in Mrs. Cavallo; is that correct? A: That’s correct. Q: What concentration — First of all, let me ask you this. What was the duration of her exposure? A: Well, I’m not sure exactly. Q: Would that be important to know? A: I’ve not found that to be essential for my assessment. ****** Q: Why is that, sir: A: Because the available information is sufficient to indicate that the exposure was of sufficient duration to cause an irritant effect on Mrs. Cavallo. (Monroe Tr., Vol I, at 50-51). Judge Ellis next turns to a discussion of the need to establish the dose-response threshold: The second step in the methodology requires the toxicologist to consult the published literature to ascertain a dose-response relationship for the particular chemicals at issue. Dr. Monroe agreed in his deposition that “there should be a threshold below which irritant effects do not occur,” and he conceded that he did not know the specific threshold for the chemicals to which Ms. Cavallo was exposed. (Monroe Tr., Vol II, at 37). Nonetheless, he stated that the literature and studies he reviewed provided ample support for his conclusion that Ms. Cavallo’s one-time exposure to AvJet for a period of 5-30 minutes at a concentration of 61 mg/ m caused her chronic conjunctivitis and her heightened chemical sensitivity. It is important here to quote a portion of Footnote 13 to this text: Notably, Dr. Monroe acknowledged that he could find no literature supporting the proposition that exposure to AvJet at a concentration of 61 mg/m for 5-30 minutes could cause Ms. Cavallo’s sinusitis. Judge Ellis then deals more specifically with the inadequacies and unreliabilities of the plaintiffs proof: The reliability of Dr. Monroe’s opinion that the AvJet spill caused Ms. Cavallo’s chronic condition is further undermined by the fact that the information that has been gathered specifically on AvJet suggests that no ill effects would be expected from exposure to AvJet for the duration and at the concentration alleged in this case. As described by Dr. Rodrieks in his report, Threshold Limit Values (“TLVs”) have been established by the American Conference of Governmental Industrial Hygienists for petroleum compounds related to aviation fuel. These TLVs are based upon “the best available information from” human and animal studies as well as industrial experience, and “represent airborne concentrations of substances to -which nearly all workers may be repeatedly exposed day after day without adverse health effects.” (Rodrieks Rpt., at 7-8). According to Dr. Rodrieks’ unrefuted assessment, the TLVs for aviation fuel, “which are designed to protect workers exposed 8 hours [per] day on a chronic basis,” exceed the worst-case concentration to which Ms. Cavallo may have been exposed (61 mg/m ) on one evening by a factor of more than 10. (Rodrieks Rpt., at 8). Furthermore, Dr. Rodrieks explained that he consulted the toxicology literature to determine the “no observed effect levels” (“NOELs”) and “lowest observed effect level” (“LOELs”) in humans for acute exposure to jet fuels, kerosene, diesel, and gasoline. This consultation revealed that “[t]he worst-case air concentration for Mrs. Cavallo’s exposure modeled by plaintiffs expert (61 mg/ m = 9ppm) was at least 15 times lower than the NOELs and LOELs observed in humans.” (Rodrieks Rpt., at 9) While Ms. Cavallo contends that these NOELs, LOELs, and TLVs are heavily biased toward industry, a proposition that may well be true, she has not produced any alternative study, literature, or source that supports her conclusion that exposure to 61 mg/m of AvJet for a relatively short duration could produce the chronic illnesses from which she allegedly suffers. Cf. Conde, 24 F.3d at 814 (stating that while the plaintiffs “cite published critiques of [the defendants’] studies, the critiques only underscore the need for further studies, and do not ... establish causation”). Id. at 768-769. Footnote 27 should also be noted: At several points in her memoranda, Ms. Cavallo resorts to evidence that AvJet is toxic, and that Star knew it to be so, in an effort to support her experts’ opinions of causation. (Mem. In Opp. To Defs’ Mot. In Lim., at 3-1 (citing EPA Order)) (Supp. Mem. In Opp. Of Mot. For sum. Jud., at 3-5 (citing Texaco Material Safety Data Sheet)). Yet, as noted earlier and as readily conceded by Star, there is no doubt that AvJet, as all chemicals, can be toxic. As Paracelsus taught long ago, toxicity is a function of dose. Thus the question for causation purposes is: At what levels of exposure do what kinds of harm occur? Next the Court in Cavallo takes up the testimony of Dr. Bellanti who relied in forming his causation opinion primarily upon the methodology of differential diagnosis: Although neither party clearly explains the methodology applied by Dr. Bellanti, it appears from a review of his written report as well as his deposition testimony that he primarily applied a methodology of differential diagnosis. Thus, he determined from a review of Ms. Cavallo’s medical history, from her description of the spill incident, from his initial examination of her, and from the timing of the spill in relation to her development of symptoms, that her exposure to the petroleum hydrocarbons could have caused her chronic illnesses. Dr. Bellanti then examined other possible causes of her symptoms (such as her hi