The Scientific Basis of Causality in Toxic Tort Cases

VIII. DOE V. BLUE: A HYPOTHETICAL TOXIC TORT CASE

John Doe wore blue socks daily for more than 10 years, and then developed a melanoma skin cancer. He sued Blue Company, the manufacturer of the dye used in the socks (blue dye #2) claiming that the dye caused his cancer. Plaintiff obtained affidavits from two experts in support of his case, Bill Breakground and Donna Dyer.

Breakground earned a Ph.D. in biochemistry and then became an Assistant Professor in the Department of Toxicology at State University, where he taught biochemistry and toxicology, and conducted biological research on the effects of a class of organic chemicals that included blue dye #2. Breakground published prolifically, and consequently moved rapidly through the academic ranks to became a full professor at State University.

Animal research in the 1950s had shown that large quantities of chemicals similar to blue dye #2 produced convulsions, internal bleeding, and death from renal or cardiac failure within 1-10 hours of administration; Breakground’s research interest involved the effect of low doses of blue dye #2 over long time periods. His research goal was to determine the nature of effects produced, and the specific cellular and molecular mechanisms by which they occurred. Breakground was funded from two sources: he had a grant from the National Institute of Health (NIH) to study basic mechanisms, and a contract with the Good Drug Company (GDC) to evaluate possible side effects.

GDC had been conducting in-house research to obtain data in support of an application to the FDA for permission to sell blue dye #2 as a food additive under the trade name Blutiful® for use in canned fruits and vegetables. The FDA had requested animal data to establish the safety of Blutiful’s® proposed use. State University and GDC entered into a contract providing for Breakground to be the principal investigator in animal studies of the effects of Blutiful®. The contract provided that Breakground would administer Blutiful® to rats throughout their two year lifetime, and conduct various tests to determine whether any side effects had developed. The dose level was chosen so that, on an equivalent weight basis, a human being could not acquire a comparable dose unless he ate 1,000 times more canned fruits and vegetables than the average consumer. GDC believed the data would show that the rats were unaffected by Blutiful®. The FDA had previously agreed that such a result would justify an inference of human safety for the company’s contemplated use. Breakground’s contract allowed him to freely publish study results thirty days after they were presented to GDC.

Ultimately Breakground found that chronic administration of Blutiful® resulted in kidney enlargement, decreased fertility, and an increased incidence of skin rashes. Breakground duly communicated the results to GDC, and subsequently submitted them for publication in a peer-reviewed journal. Breakground’s results ultimately were published. In other publications, Breakground presented evidence suggesting the particular cellular pathways that mediated the observed effects. Other scientists, however, have published data implicating entirely different processes. Consequently, the issue remains unsettled.

Doe’s other expert, Donna Dyer, was the acknowledged world expert on the structure and chemical properties of blue dye #2. During a field trip to the Brazilian rain forests, Dyer found plants that had blue flowers. She took specimens back to her laboratory, extracted the coloring agent, and in a painstaking series of studies, determined its exact chemical composition and atomic structure. Thereafter, Blue Company, the defendant, used genetic engineering to create a strain of bacteria capable of producing unlimited quantities of the agent, which became known as blue dye #2, for sale to the textile industry.

Blue Company obtained affidavits in support of its position from two medical doctors, Gene Causitall and Harriet Healer, and from an epidemiologist, Frank Findit. Causitall did an internship and residency in internal medicine at a prestigious eastern university, took fellowship training in medical oncology,¹²⁸ and ultimately became Board certified in both internal medicine and medical oncology. Causitall joined the University Medical School as a faculty member in the Department of Medicine, Section of Oncology, where he became professor and head of the Section of Medical Oncology. Causitall routinely treats patients with a variety of different kinds of cancer, including melanoma. Causitall also heads an extensive research effort aimed at understanding the molecular basis of cancer. His hypothesis is that cancer is caused by a particular gene carried by viruses. Causitall’s research has led to many peer-reviewed publications involving cellular and animal studies of the putative oncogene.

Harriet Healer operates a private clinic that specializes in the diagnosis and treatment of melanoma, and patients are referred to her for treatment from all over the United States, and from abroad. She uses a variety of different combinations of accepted treatments for melanoma, in an attempt to improve the five-year survival rate which, unfortunately, is still quite low.

Frank Findit is chairman of the Department of Epidemiology at State University. Findit wrote a textbook on epidemiology and published more than 100 epidemiological studies, including studies of the relationship between cigarette smoking and heart disease, asbestos and lung disease, and agricultural pesticides and cancer in farm workers.

After submitting the experts’ affidavits, Blue Company moved to strike the testimony of Breakground and Dyer because they were unqualified to offer medical testimony. Blue Company also moved to dismiss the suit because the theory that blue dye #2 can cause cancer is not generally accepted. Doe opposed the motions. In addition, Doe moved to limit Healer’s testimony to the diagnosis and treatment of melanoma and to medical matters involving Doe’s medical condition, and to exclude her testimony dealing with causation of cancer. Doe also moved to limit Findit’s testimony to epidemiological studies and the inferences reasonably be based thereon, and to exclude any testimony from Findit involving animal studies. In his deposition, Findit cited reports of various blue-ribbon committees to support his conclusions. Doe moved to exclude the use of these reports except for purposes of impeachment.

Judge Learned was called on to resolve the issues, and he ruled as follows.

The disputes regarding the experts’ qualifications will be considered first. The issue presented by a motion to exclude an expert witness for lack of qualifications is not whether the proffered witness is the best imaginable, the best available, or one of the most knowledgeable; rather, it is whether the witness is minimally qualified to offer the testimony. Dr. Breakground was formally trained in the scientific methods and procedures for inferring causal relationships, and the many scientific studies he published in the peer-reviewed literature provide evidence of a proficiency regarding that process. Further, Breakground has had many years’ experience studying the biological effects of blue dye #2 and related chemical compounds and has, himself, contributed to that area of science. Since he has measured, administered, and controlled the application of blue dye #2 in scientific studies, this provides a reasonable indication that he can evaluate the dose aspects of the application and administration of the dye by others. Dr. Breakground is therefore qualified to offer testimony regarding the implications of the scientific literature with regard to the biological effects of blue dye #2, including its alleged causal role in the development of plaintiff’s cancer.

Dr. Dyer is not qualified to offer opinion testimony regarding the biological effects of blue dye #2 because her expertise is limited to measuring, characterizing, and elaborating the structure and nature of blue dye #2 in relationship to other chemical compounds. She has not conducted studies to ascertain what effects might reasonably be expected from the dye when it is introduced into the body of animal or human subjects. As an expert on the chemical properties of blue dye #2, however, the court will permit testimony from Dr. Dyer regarding non-causal issues that may be relevant such as the solubility of blue dye #2 in weak salt solutions which, it has been alleged by plaintiff, is important to an understanding of how the dye in plaintiff’s socks actually entered plaintiff’s body through his sweat. Thus, the court will accept Dyer as an expert on the chemical properties of blue dye #2 and her testimony will be limited to that topic.

Dr. Causitall was trained as a physician but thereafter acquired the skills and abilities of a scientist as demonstrated by his many contributions to the scientific literature dealing with the role of genes in causing cancer. It is not possible to determine, prior to trial, the extent of Dr. Causitall’s experience with regard to chemical cancer-causing agents in general, or blue dye #2 in particular, but those matters will be resolved during the trial and will bear directly on the weight to be afforded his testimony. As a practicing scientist with a demonstrated history of knowledge of factors that can cause cancer, Dr. Causitall has at least the minimal qualifications required of a causal expert in this case.

Dr. Healer’s background gives no indication of training or experience in scientific principles and practices. The court recognizes her superior clinical skills in the diagnosis and treatment of melanoma, but the existence of those skills does not imply knowledge regarding the proper manner for inferring the cancer-causing potential of a putative carcinogen from the pertinent scientific studies. It is common knowledge among oncologists that certain agents are carcinogenic, and if this case involved such an agent, a court might indeed find Healer’s opinions helpful. However, the knowledge respecting cancer causation that is required in this case, if it exists at all, is not commonly known among oncologists. This knowledge must be inferred from the scientific data, and Dr. Healer has not shown that she possesses the requisite skill to do so. Consequently, Dr. Healer’s testimony shall be limited to issues that may arise involving the diagnosis and treatment of melanoma, and to medical opinions regarding plaintiff’s diagnosis or prognosis.

Dr. Findit is a trained and experienced expert in performing and evaluating human studies involving the possible association of various environmental factors and diseases. He is, consequently, qualified to offer opinions concerning the implications of the human studies involving blue dye #2 with respect to its association with cancer. The record does not reveal the extent of Dr. Findit’s knowledge concerning dosimetry of chemicals in general, or blue dye #2 in particular, but it will be the responsibility of the trier of fact to determine whether his knowledge in this area is sufficient to form a reasonable basis for evaluating the various studies. Dr. Findit, however, has had no experience performing laboratory studies involving animals, and thus there is no basis for the court to accept him as an expert in evaluating animal studies with regard to cause-and-effect relationships, or in particular with regard to the implications they may have for the cancer-causing capability of blue dye #2. Consequently, Dr. Findit’s testimony will be restricted to an evaluation of the human studies, and the jury will determine whether it is reasonable to base conclusions solely on such studies.

The Court will now consider the reliability of the proffered testimony. Before doing so, however, the court will directly address the defendant’s argument that the appropriate place to decide scientific issues is in the laboratory, not the courtroom. This court agrees with this view, provided that the issues are such that it is appropriate that they be decided in the laboratory. The issues in this case, especially the question whether blue dye #2 can cause cancer, will be resolved according to the standards of certainty and concepts of causality that are routinely followed in the law. The law does not require near certainty, or clear and compelling evidence prior to assessing liability or reaching other final determinations that affect the rights and relationships between individuals. While it is true that the scientific community may find little value in this court’s decision regarding the role of blue dye #2 in causing cancer because of the court’s failure to apply what science might consider to be the applicable standard for a scientific decision, it is similarly true that this court would not be bound or guided by any purely scientific decision against the possible causal role of blue dye #2 because the scientific standard for certitude far exceeds that of the law in civil cases. The court concludes, therefore, that its consideration regarding whether blue dye #2 can cause cancer as determined by a preponderance of the evidence is not such a scientific issue that must be decided in the laboratory, but rather that it is a legal question and therefore appropriate for consideration in the courtroom.

Dr. Breakground’s affidavit described ten animal studies published in the peer-reviewed scientific literature, including two studies that he performed, which showed a variety of biological effects in animals that had been exposed to blue dye #2. In the studies, which were performed on rats, mice, and rabbits, weak solutions of the dye were applied daily to the skin on the leg or the back of the animals, which were then killed at various times to obtain tissue specimens for the purpose of evaluating the effect of chronic administration of the dye; the experiments lasted for one year in the rats and mice, and two years in the rabbits.¹²⁹ None of the animal studies actually showed that blue dye #2 increased the rate of cancer in the exposed animals, but the studies did reveal a variety of adverse effects¹³⁰ in the animals, thereby providing a reasonable basis to conclude that the dye was potentially hazardous. Since such studies are frequently performed to establish the safety of an agent by the process of inference from negative study results, it must also be valid to make a contrary inference when positive results of a certain type are found—otherwise, there would be no reason to perform the studies in the first instance.

Dr. Breakground also cited ten epidemiological studies, including two that he co-authored, involving the occurrence of cancer among workers in the chemical dye industry, and among residents who lived in neighborhoods near factories that manufacture chemical dyes. Two of the studies reported a statistical association between workers who manufactured blue dye #1 and leukemia, and another study found an association between red dye #1 and brain cancer; both dyes were similar in chemical composition, though not identical to blue dye #2. Three studies showed an association between cancer, regardless of type, and living near chemical dye factories. Four studies were performed on workers in the textile industry who routinely handled cloth that was colored with blue dye #2. In 3 of the studies, significantly increased rates of cancer of the eye, brain, breast, and colon were observed. However, a consistent elevation in each type of cancer, considered alone, was not observed. None of the ten studies specifically involved the relationship between blue dye #2 and melanoma. Dr. Breakground concluded that the animal and human studies, taken together, showed that blue dye #2 could cause cancer in human beings.

Dr. Dyer performed calculations based on the established chemical properties of blue dye #2, the average number of hours per day that plaintiff’s feet were in contact with the blue socks, the number of years he wore blue socks, the change in concentration of the blue dye in the socks depending on the number of times they were washed, the salt content of human sweat, and other pertinent factors. He concluded that the dose of blue dye #2 experienced by plaintiff was 1 microgram per day throughout the 10-year period between the time that he started wearing blue socks and the diagnosis of his melanoma. Dr. Breakground compared this value with the dose of blue dye #2 employed in the animal studies and the estimated amount of chemical dye that was inhaled by residents near the dye factories in the epidemiological studies in forming his opinion that blue dye #2 caused plaintiff’s cancer.

Dr. Causitall was unimpressed with the published studies involving the biological effects of blue dye #2. He said that several of the animal studies were seriously flawed in the way they were conducted, and in other cases the changes produced were small and could therefore easily be handled by the body with no adverse effects; consequently, these studies did not warrant an inference that similarly exposed humans would be at any kind of a risk. Dr. Causitall deferred to Dr. Findit’s evaluation of the epidemiological studies but agreed with him regarding the overall inconclusiveness of the human studies. Dr. Causitall also listed seven animal studies funded by Blue Company that failed to find any effects of blue dye #2, and concluded that since there were almost as many negative studies as positive studies, it would be unreasonable to conclude that the evidence showed the dye could be a health risk.

Dr. Causitall pointed approvingly to a report by the state health department which concluded that no health risks due to dye that escaped from dye factories had been conclusively proven, and to the results of an analysis by a panel of the American Association of Specialists in Toxicology that studied the health-risk issue associated with chemical dyes and concluded that there was no convincing evidence that the dyes constituted a human health risk. Dr. Causitall concluded that, despite the concerted effort made to uncover any health hazards from blue dye #2, no clear evidence that such hazards actually exist had been discovered, from which it can be inferred that there are none, and consequently that blue dye #2 is safe, as was concluded by the various authoritative groups that considered the issue.

The defendant’smotion to dismiss, if granted, would be a substantive determination of plaintiff’s rights because if it were true that the scientific evidence were unreliable when offered by Dr. Breakground, a qualified expert, then it would be unreliable when offered by any other expert. Since evidence concerning scientific causality can only be presented by an expert, plaintiff would effectively be precluded from obtaining his day in court. Consequently, the motion to dismiss will be treated as a motion for summary judgment, and the disputed items of fact will be viewed in favor of plaintiff.

The seminal issue is whether the proposition that blue dye #2 can cause cancer is true, or can reasonably be said to be true, based on the available scientific evidence. By “cause” is meant that a population exposed to blue dye #2 will show a greater incidence of cancer than the same population would have shown in the absence of the added dye.¹³¹ Even educated and greatly respected persons may not offer expert testimony in the courts of this state unless they possess knowledge of the type needed in the case. Scientific experts must possess scientific knowledge, which is that material and information contained in the scientific journals and publications that are traditionally used to disseminate and memorialize such information. Breakground cited 10 animal studies and 10 human studies and based thereon specifically affirmed that the dye can be carcinogenic in human beings. Dr. Causitall appears to conclude that blue dye #2 does not cause cancer in human beings, whereas Dr. Findit says that there is not enough evidence to support Dr. Breakground’s position, and thus does not agree that blue dye #2 can cause cancer. The methods and procedure followed by Dr. Breakground in reaching his conclusion were in accordance with those normally followed in determining whether any particular factor can be responsible for producing biological changes. Dr. Breakground relied on animal and human studies that were published in the peer-reviewed literature and which, therefore, can properly be viewed by the expert and this court as evidence of the truth of what they purport to show. Thus he can properly employ these studies to form inductive inferences. Drs. Causitall and Findit disagree with Dr. Breakground regarding the scientific integrity of some of the studies, but until these witnesses are subjected to cross-examination it will not be possible to determine which view of the studies is correct.

Drs. Causitall and Findit cited many negative studies in support of their position, and since negative studies can be probative, depending on what other studies may also exist, some concern is raised by Dr. Breakground’s failure to discuss the negative studies. On the other hand, neither of the defendant’s experts raised a negative study in the context of directly opposing or invalidating an inference that could otherwise be drawn from any particular positive study. Thus it appears that the negative studies cited by the defendant’s witnesses were performed under conditions and circumstances that differed materially from those attendant the positive scientific studies. Consequently, it is possible that all the positive studies cited by plaintiff and all of the negative studies cited by the defendant are scientifically valid. If so, it would follow that the negative studies were simply not probative with regard to plaintiff’s inductive inference that blue dye #2 can cause cancer. Again, these are factual matters that can be resolved only upon trial.

The court has carefully considered the report by the state health department upon which Dr. Findit relied. The court is sensitive to defense counsel’s argument that the state health department contains experts in the fields of epidemiology and public health, among other scientific disciplines. The health department is therefore in a position superior to that of the court with respect to determining whether blue dye #2 can cause cancer. The argument of counsel is, however, not persuasive because both the goal and the methods of the health department are far different than those of this court. The health department must consider both the scientific evidence regarding risk and the financial burdens that might result from any decision before it makes a finding that might involve remedial action resulting in great costs, or that could lead to apprehension and concern by the public of possible health hazards. Such a risk-benefit analysis is a fundamental part of the evaluation of the health hazards of a toxic agent by a state agency. But it is not pertinent to the issue in this case whether blue dye #2 can cause cancer because that must be decided solely on the basis of scientific knowledge.

The health department report is also inadmissible as evidence of the truth of what it says for the reason that its authors cannot be cross-examined. Although the report was jointly written by five staff scientists, it was adopted and issued by the health department, and is therefore an official report of the health department. The officials who speak for the department are appointed by the governor, and they cannot be required to explain and defend their discretionary acts. The department staff persons who drafted the report can not speak for the department. Therefore, whatever value the health department report might have in other forums, it is not admissible in court as evidence of the truth of the facts that it recites. It should be noted that the defendant is free to present one or more of the authors of the report in their private capacity, and through them to place into evidence the scientific knowledge upon which the conclusions of the report are based.

Dr. Findit also relied on a report by a blue-ribbon panel of professional toxicologists, but the court has no way of evaluating the basis upon which the experts reached their opinion, the fidelity of Dr. Findit’s description and characterization of the panel’s report, or the extent to which the panel members may have been affected by bias arising from consulting and other financial relationships between one or more of the panel experts and the defendant in this case. If the defendant believes that the committee’s report contains information relevant to this case, then the proper way to introduce it would be for the defendant to call one or more of the experts from the committee and elicit the requisite testimony. It is not the committee report that is relevant to this case, but rather the scientific knowledge that was relied upon in forming the conclusions reached in the report, and the methods by which the conclusions were reached.

The issue of potential bias among scientists is important, and it must be specifically addressed during trial. If, as plaintiff alleges, several of the studies relied upon by the defendant were designed and controlled by the defendant, then the jury would be justified in discounting the data obtained from them. For each study that forms an important part of the basis of any expert’s conclusion, an inquiry regarding how that data was obtained must be made, and a determination reached regarding whether the data was produced by one of the parties in contemplation of litigation.

Many factual issues remain to be resolved, and plaintiff is entitled to a favorable view of the disputed facts under a motion for summary judgment. Since numerous supportive scientific studies have been cited by plaintiff, the court concludes that it is reasonably possible that blue dye #2 can cause cancer.

Plaintiff’s witness, Dr. Dyer, concluded that plaintiff received a specific amount of blue dye #2 into his body as a consequence of the prolonged direct contact between the dyed material and his skin. Dr. Breakground testified that the dose level calculated by Dr. Dyer was equal to or greater than the dose levels employed in most of the scientific studies upon which he relied, and that members of the public ordinarily do not receive doses of blue dye #2 as great as that said to have been received by plaintiff. Dr. Findit disputes both the dose level received by plaintiff and the doses received by ordinary persons who do not develop cancer, and these issues must be resolved at trial, where the assertions of various experts can be tested upon cross-examination. Also to be considered at the trial is the issue of the presence of any confounding factors with regard to the causation of plaintiff’s cancer. For plaintiff to validly conclude that his cancer was caused by blue dye #2, the possible role of other known cancer-causing factors must be eliminated because plaintiff’s rationale is based on a process of elimination of other possible causes. The proper forum for evaluation of these matters, however, is at trial, and not on a motion for summary judgment. The defendant’s motion, therefore, is overruled.

Based on these various considerations, Judge Learned denied the motion for summary judgment and issued an order limiting the testimony of the witnesses and the use of various reports in accordance with the findings recited in his opinion.