Ferebee Revisited

The following post was originally published on November 8, 2012, but was hacked, no doubt by the lawsuit industry, and replaced with mindless fluff as is its wont. It is now restored.

Ferebee Revisited

I used to think of the infamous Ferebee decision as the Dred Scott decision of scientific evidence; in essence, declaring that science has no validity issues that the law is bound to respect. Ferebee v. Chevron Chem. Co., 552 F. Supp. 1297 (D.D.C. 1982), aff’d, 736 F.2d 1529 (D.C. Cir.), cert. denied, 469 U.S. 1062 (1984). The rhetoric on expert witnesses, from the district and circuit courts in this case is sometimes jarring, but the facts of the case make the holding, rather than the expansive dicta, not so unreasonable, under all the facts and circumstances of the case.

On rereading Ferebee, I was struck by several aspects of the case that rarely are discussed when Ferebee is cited. On sober second thought, Ferebee may not be such a bad decision, especially considering that it has no continuing validity as a rule of decision for expert witness admissibility in federal court.

1. Ferebee is a government negligence case.

The plaintiff worked for the federal government when he was exposed to the herbicide paraquat. Richard Ferebee began working for the Department of Agriculture’s Beltsville Agricultural Research Center (BARC), in Beltsville, Maryland. He started spraying paraquat in the summer of 1977, and used the herbicide regularly through the time he was diagnosed with pulmonary fibrosis, in November 1979. 736 F.2d at 1531-32. Ferebee brought a failure to warn claim against the supplier of paraquat, Chevron Chemical Company. The allegations of actual or constructive knowledge of a hazard, however, could just as readily be asserted against the federal government, which owned the BARC facility, employed Ferebee, controlled and supervised his use of paraquat, and failed to comply with Chevron’s instructions. The federal government further regulated the sale and use of paraquat extensively, first by the Department of Agriculture, and later by the Environmental Protection Agency. Id. at 1532.

2. The exposure.

Ferebee filed suit in 1981, he died in 1982. His case was tried twice. In the first trial, the jury deadlocked; in the second trial, the jury returned a verdict in favor of his estate, and for his family, for $60,000. In his deposition testimony, Ferebee described how sprayed paraquat, in the summer of 1977. The chemical was diluted for use, per Chevron’s instructions. There was no evidence that Ferebee ever had direct contact with undiluted paraquat, or that the paraquat he was exposed to was not diluted according to the proportions recommended on Chevron’s label. 552 F. Supp. at 1295 & n. 3. Ferebee frequently got the chemical on his hands. 552 F. Supp. at 1294-95. Ferebee further described an occasion when he was drenched with paraquat when he walked behind a tractor that was spraying the chemical, and another incident when he used a defective sprayer that leaked paraquat “all over his pants.” 736 F.2d at 1532. On both occasions, Ferebee did not wash, and apparently went home contaminated, where he fell asleep, tired and dizzy, without showering. Id. As we will see, the exposure that Ferebee described would not have occurred had his federal employer followed the instructions on the label that it mandated. In 1978, the federal Occupational Health & Safety Administration published Guidelines on the need for protective clothing, respirators, immediate washing of contaminated skin, etc. Ferebee’s federal employer recklessly disregarded its own guidelines.

3. The warnings.

Paraquat could be sold in the United States only when labeled in accordance with EPA regulations, promulgated pursuant to the Federal Insecticide, Fungicide, and Rodenticide Act, 7 U.S.C. § 136, et seq. (FIFRA) The statute bars EPA from allowing sale of regulated herbicides, such as paraquat, unless the chemicals, as labeled, will not cause “unreasonable adverse effects on the environment.” 7 U.S.C. § 136a(c)(5)(C). Such effects are in turn defined as any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of [the] pesticide. 7 U.S.C. § 136(bb). FIFRA further requires the EPA to require labeling that is “adequate to protect health and the environment” and that is “likely to be read and understood.” 7 U.S.C. § 136(q)(1)(E). 736 F.2d at 1539-40.

Unfortunately, the courts failed to provide the complete warning label and the material data safety sheets. There are “snippets” provided, which make clear that the federal government was largely to blame for failing to comply with the directions required under FIFRA. For instance, the district court, in a footnote, acknowledged:

“For example, the label advised the user spraying paraquat to wear waterproof clothing and goggles, to avoid working in spray mist, and to wash splashes on the skin or eyes immediately with water.”

552. F. Supp. at 1304 n.40. The Court of Appeals reported that “the label, in large bold letters states:




736 F.2d at 1536. The label also informed users to wash any exposed areas immediately, and to remove contaminated clothing. Id.

4. The Stipulation.

A key fact, rarely described or explained in discussions of the Ferebee case, is the parties’ stipulation

“that Mr. Ferebee’s only significant exposure to paraquat was on his intact skin; i.e., there was no evidence that Mr. Ferebee swallowed or inhaled paraquat, or that he spilled or sprayed it on an area of his skin upon which he had any apparent cuts or scrapes. The jury was not, of course, precluded from concluding that a person engaged in Mr. Ferebee’s line of work could have had some, or even many, minor cuts or abrasions not readily discernible to the naked eye or likely to be remembered some time later.”

552. F. Supp. at 1295 & n. 3.

Why did the plaintiffs try to present their case solely as a dermal exposure cases? As we will see, this stratagem made their medical causation case more difficult, but it avoided serious misuse and lack of proximate cause issues. Ferebee had been instructed by his co-workers and supervisors that paraquat was extremely dangerous if swallowed, and probably also if inhaled. The warning label was unequivocal in detailing the dangers and the need to avoid ingestion. (Without the full label, it is difficult to evaluate how well the label warned against inhalation, but the 1978 OSHA guidelines address the use of a proper respirator for situations in which paraquat may be inhaled.) On the other hand, the label had a weakness, which could be exploited, as long as the preemption defense could be held at bay: the label urged protective clothing, goggles, and immediate washing of contaminated skin, but it failed to describe the consequence of dermal exposure other than irritation. Ferebee could thus avoid his culpable conduct, as well as a sophisticated intermediary defense, by claiming that his exposure was only dermal.

Why did Chevron agree to the stipulation? The defendant probably felt sanguine about its preemption defense, and thus also about the adequacy of its warnings overall. The stipulation limited the plaintiff’s medical causation case to a route of exposure that put it into an arguable “first instance” case report. Chevron stood to gain a claim of “lack of notice,” and thus lack of actual or constructive knowledge of the risk of lung disease from dilute dermal exposure. The clinical presentation itself differed from many of the cases of known paraquat poisoning, see infra, and Chevron probably believed that it could deal with the medical causation claim better if exposure was limited to transdermal absorption. Curiously, Chevron did not argue that Ferebee must have had some inhalational exposure, which he almost certainly did. I suspect that Chevron’s position on inhalation was hedged because its warning label did not specify respirator usage for ordinary work exposures of applicators (as opposed to workers who handled undiluted paraquat, worked in confined spaces, etc.).

5. Medical causation

Chevron took a strident position, standing on the fact that there had been no previous documented cases of pulmonary fibrosis in workers exposed to diluted paraquat through their skin. The following facts were uncontroverted:

  • Paraquat causes pulmonary fibrosis in humans.
  • The evidence that established paraquat as a cause of pulmonary fibrosis was largely case series of acute onset of pulmonary fibrosis after ingestion.
  • Paraquat induces pulmonary fibrosis relatively rapidly.
  • Paraquat can be absorbed through the skin.
  • The parties agreed that any type of exposure – ingestion, inhalation, or dermal absorption – could cause lung damage. 552. F. Supp. at 1300 & n.28.
  • Once paraquat is ingested, inhaled, or absorbed, it can travel to the lungs.
  • Lung fibrosis caused by dermal absorption of paraquat had been described previously only with skin lesions before or after the injury. 736 F.2d at 1538.
  • The lungs are the target organ for paraquat.
  • There are numerous causes of pulmonary fibrosis (such as asbestosis, scleroderma, rheumatoid arthritis, etc.).
  • The variants of pulmonary fibrosis do not all look alike, present alike, or progress alike.
  • Mr. Ferebee had no known other disease or exposure that could account for his pulmonary fibrosis.
  • There is are cases of pulmonary fibrosis with no identifiable cause, known as idiopathic pulmonary fibrosis (IPF).
  • IPF is relatively rare; it too has a rapid onset and progression, although not as fast as the cases described after exposure to undiluted paraquat.
  • Mr. Ferebee’s medical history was largely unhelpful in explaining his clinical course.
  • Ferebee had some shortness of breath before starting to use paraquat. 552. F. Supp. at 1295.
  • Ferebee used paraquat occasionally over three years before he was diagnosed with pulmonary fibrosis.

Some observations about these facts. General causation in a sense was not contested. Paraquat causes pulmonary fibrosis. The issue was whether dilute dermal exposure over three years causes pulmonary fibrosis. Chevron stridently asserted that the “scientific method” required controlled experimental or observational (epidemiologic) studies. The problem with Chevron’s position was that general causation had already been established, and not by analytical epidemiologic studies.

6. The expert witnesses.

Ferebee was initially treated by Dr. Muhammed Yusuf, a pulmonary specialist, who diagnosed pulmonary fibrosis. Dr. Yusef referred Ferebee to the National Institutes of Health (NIH), where he came under the care of Dr. Ronald G. Crystal of the Heart, Lung, and Blood Institute. (Dr. Crystal is now at Cornell-Weill, where he is Chairman of Genetic Medicine, and he practices pulmonary medicine.)

Chevron called Dr. Carrington, who diagnosed Ferebee with IPF. Dr. Carrington challenged the plaintiffs’ expert witnesses’ opinions for lacking reliance upon controlled observational or experimental studies. 552. F. Supp. at 1301. Dr. Carrington, however, acknowledged that dermal cases are too rare for observational epidemiologic analysis, but emphasized that no animal studies of sufficient size had been done to support plaintiffs’ hypothesis. Chevron also called a Dr. Fisher, who presented a toxicokinetic (TK) analysis of Ferebee’s dermal absorption. Based upon his TK analysis, Dr. Fisher concluded that the maximal amount of paraquat absorbed by Ferebee was too small, based upon known cases and animal studies, to have caused paraquat toxicity. Id.

7. Chevron’s challenge to plaintiffs’ expert witnesses’ causation opinion.

None of the defendant’s expert witnesses examined Ferebee. The courts thought this was relevant, but they never articulated what would have been observed on physical examination that was important to resolving the differential diagnosis of paraquat toxicity versus IPF. There was no dispute that Ferebee had rapidly progressing pulmonary fibrosis. The expert witnesses on both sides evaluated Ferebee’s clinical data, presentation, clinical course, and arrived at different diagnoses. The plaintiffs’ expert witnesses’ diagnosis, however, involved a causal attribution to paraquat exposure.

The Ferebee case was litigated under Maryland law because federal statutory law requires state law to control in a wrongful death action arising out of the neglect or wrongful act of another on a federal enclave. 16 U.S.C. § 457. 736 F.2d at 1533. (Maryland law is actually favorable to a sophisticated intermediary defense, although the key decisions post-date Ferebee.) Chevron appears to have relied upon Maryland’s articulation of the Frye general acceptance doctrine, and the courts analyzed Chevron’s arguments as a Frye challenge. 552 F. Supp. at 1301; 736 F.2d at 1535. Although the use of Maryland law to determine an evidentiary issue seems suspect, Chevron pressed apparently pressed its challenge in terms of Maryland’s version of Frye, and not based upon Federal Rule of Evidence 702. The infamous language used by both the district and the circuit courts was, therefore, not an interpretation of federal law. Rule 702 was never cited or discussed in either the trial or the appellate court’s opinion.

My re-reading of Ferebee has softened my criticisms of state courts that had relied upon the case, even after the Supreme Court’s decision in Daubert. Softened but not eliminated my criticism — Ferebee is still a case largely confined to its facts, and the language quoted as a standard of admissibility is really a statement of the appellate standard of review for the jury’s determination of medical causation.

8. The judicial resolution of Chevron’s Frye challenge

The district court insightfully recognized that Chevron was demanding a level of evidence, which had never been required to establish paraquat’s generally accepted ability to cause pulmonary fibrosis. This recognition led to the district court’s colorful language:

“It is true that medical expert testimony must be grounded in proper scientific methodology, but the extremely stringent standard that defendant suggests is beyond reason. Product liability law, especially as it relates to relatively new products or those with a relatively rare yet significant danger, would be rendered next to meaningless if a plaintiff could prove he was injured by a product only after a ‘statistically significant’ number of other people were also injured. A civilized legal system does not require that much human sacrifice before it can intervene. The fact that this is the first case of this exact type-or at least the first of its exact type in which the involvement of paraquat was discovered by alert doctors — cannot be enough by itself to shield defendant from liability. Defendant’s experts were not able to fault Dr. Crystal for his basic diagnostic methodology; in fact, they used the same kinds of test results, consultations, and other tools that he did. What they disagreed with chiefly were his conclusions.”

552 F. Supp. at 1301. The important observation is that general causation had been established case series and reports of human exposure. There never was statistical evidence that had been evaluated for “significance,” to establish general causation for undiluted paraquat, and the trial court refused, under Maryland law, to require such evidence for general causation for diluted paraquat. In this context, we can see that the trial court’s suggestion that statistical significance was not required has little bearing upon, cases in which general causation could only be established using epidemiologic evidence, with its attendant statistical inferences.

Of course, the matter only became worse when Chevron persisted in its argument and presented it to a liberal panel of the D.C. Circuit. (Judge Mikva wrote the opinion for a panel that included Judge Wald, and Senior Judge Bazelon.) The panel’s decision ratcheted up the rhetoric:

“Thus, a cause-effect relationship need not be clearly established by animal or epidemiological studies before a doctor can testify that, in his opinion, such a relationship exists. As long as the basic methodology employed to reach such a conclusion is sound, such as use of tissue samples, standard tests, and patient examination, product liability does not preclude recovery until a ‘statistically significant’ number of people have been injured or until science has had the time and resources to complete sophisticated laboratory studies of the chemical. In a courtroom, the test for allowing a plaintiff to recover is not scientific certainty, but legal sufficiency; if reasonable jurors could conclude from the expert testimony that paraquat more likely than not caused Ferebee’s injury, the fact that another jury might reach the opposite conclusion or that science would require more evidence before conclusively considering the causation question resolved is irrelevant. That Ferebee’s case may have been the first of its exact type, or that his doctors may have been the first alert enough to recognize such a case, does not mean that the testimony of those doctors, who are concededly well qualified in their fields, should not have been admitted.”

736 F.2d at 1535-36 (emphasis in original).

Again, the dismissive attitude towards statistically significant evidence is limited to the context of a causal analysis that had been made, to everyone’s satisfaction, for undiluted paraquat, without the need for epidemiologic, statistical evidence. Statistical significance was never at issue. In this way, Ferebee resembles the untoward language on statistical significance from Matrixx Initiatives Inc. v. Siracusano. In both cases, statistical significance was never really at issue. In Ferebee, there was no statistical evidence needed or used to reach causal conclusions about paraquat’s ability to induce pulmonary fibrosis. In Matrixx Initiatives, allegations of statistical significance and causation were not necessary because the plaintiffs needed only to allege materiality of the facts suppressed by the company in order to plead a securities fraud case. Materiality could be established without causation, and thus neither causation nor statistical significance needed to be alleged.

As for Chevron’s Frye challenge, the district court rejected the implied call for a vote on the general acceptance of Dr. Crystal’s reasoning. Frye may require “vote counting” of some sort, but the process becomes irrelevant when virtually no one has registered to vote. Otherwise, the defense and the plaintiffs’ expert witnesses appeared to be using the same technique of arguing by analogy to accepted cases of paraquat poisoning or IPF. Dr. Crystal opined that Ferebee’s case was “similar” to three other cases he had identified. Dr. Carrington argued that Ferebee’s case was more like IPF cases, although IPF cases themselves have some clinical heterogeneity as well. Paraquat cases described onset to death as a very rapid process. Ferebee did not present with significant symptoms for three years after his first exposure, and then he survived for another two plus years. Ferebee did not report skin lesions, which had been reported in previous cases of dermal exposure leading up to pulmonary fibrosis. The case presented, on the diagnostic level, a difficult call, but it is easy to see the courts’ impatience with the defendant’s insistence upon more stringent criteria and evidence than was used to establish the causal connection with undiluted paraquat.

9. Expert witness qualifications.

Chevron never challenged Dr. Yusuf’s or Dr. Crystal’s qualifications. The oft-quoted comments about expert witness qualifications were made in the context of describing the appellate court’s standard of review, and the court’s role in not assessing credibility or weighing the evidence:

“These admonitions apply with special force in the context of the present action, in which an admittedly dangerous chemical is alleged through long-term exposure to have caused disease. Judges, both trial and appellate, have no special competence to resolve the complex and refractory causal issues raised by the attempt to link low-level exposure to toxic chemicals with human disease. On questions such as these, which stand at the frontier of current medical and epidemiological inquiry, if experts are willing to testify that such a link exists, it is for the jury to decide whether to credit such testimony.”

736 F.2d at 1534.

This procedural posture is obviously very different from the initial determination of admissibility. As far as credentials are concerned, Drs. Yusuf and Crystal were hardly “hired guns”; both physicians were well qualified. Dr. Crystal had outstanding qualifications, and Chevron wisely never challenged them. Remarkably, this language has been mistakenly invoked as a standard for trial courts to use in determining the admissibility of expert witness opinion testimony. It is no such thing.

10. Preemption and Warnings Causation.

Ultimately, Chevron’s preemption defense was rejected by both the district and the circuit court. FIFRA preemption has had its ups and downs; no surprise there. More interesting is the emphasis that both courts gave to the important role of the employer in the case. The evidence overwhelming showed that Ferebee had never read the warning label, and thus the element of proximate causation between allegedly inadequate warning and harm was in jeopardy of going unproved. The courts, however, emphasized the role that the employer, through its supervisors and responsible co-workers, play in the complex organizational situation of a modern workplace:

“Mr. Ferebee’s situation was quite different, however. He did not purchase paraquat for his personal use; rather, it was provided to him by his employer for use on the job. The evidence showed that his principal source of information about paraquat was the oral instructions of his supervisors and co-workers, not the written label. He learned from them how to mix the product and how to spray it. It was also from this source that he learned of the danger of getting the product in his mouth: one of his co-workers warned him that if he accidently swallowed paraquat, it would ‘get in his blood’ and poison him. This is a common pattern of instruction and use of occupational materials in the workplace. Learning by doing and learning by oral instruction are tried and true methods of educating manual workers in their jobs. Therefore, although it is crucial to plaintiff’s case that someone would have read the label, it was not necessary for Mr. Ferebee to have done so. And it is obvious that one or more employees at BARC did read the label, since information did reach Mr. Ferebee about the proportions for diluting the product and about the dangers about which the label did warn. It was appropriate for the jury to infer that a warning about the danger of fatal lung disease from dermal exposure would also have been communicated to Mr. Ferebee. See Restatement (Second) of Torts § 388 comment n (seller normally entitled to assume that adequate warning will be passed on by purchaser to ultimate user); cf. Chambers v. G.D. Searle & Co., 441 F.Supp. at 381 (in product liability case involving prescription drug, relevant warning is the one given to doctor, not patient).”

552 F. Supp. at 1303-04 (internal citations omitted). So here we have Ferebee, the subject of so much derision and aspersion from defense counsel, embracing the Section 388, comment n, as well as applying learned intermediary principles to a case not involving prescription drugs. The appellate court was waxed enthusiastic about the principles of Section 388, and went so far as to cite Victor Schwartz in support:

“We live in an organizational society in which traditional common-law limitations on an actor’s duty must give way to the realities of society. *** In this case, Mr. Ferebee did not purchase the paraquat for his personal use, and there was substantial evidence that workplace communication about the dangers associated with various chemicals usually took the form of oral instructions from supervisors to workers, the latter of whom then retransmitted the information to co-workers. This, rather than individual reading of product warnings, is a typical method by which information is disseminated in the modern workplace. See Schwartz & Driver, “Warnings in the Workplace: The Need for a Synthesis of Law and Communication Theory,” 52 U. Cinn. L. Rev. 38, 66-83 (1983). The requirement that an improper warning proximately ‘cause’ the injury should be elaborated against this background. We believe Maryland would construe its tort law in this case to require only that someone in the workplace have read the label, not that Mr. Ferebee personally have read it. Because there is no dispute that one or more employees at BARC did read the label, we hold that the jury could properly have inferred that, had a warning about the danger of disease from dermal exposure been included on the label, that warning would have been communicated to Mr. Ferebee and that he would as a result have acted differently. Alternatively, the jury could have inferred that an adequate warning would have led Ferebee’s employers to undertake steps that would have protected him from paraquat poisoning-for example, provision of showers for use after spraying.”

736 F.2d at 1539 (emphasis in original; internal citation omitted). Judge Mikva’s prediction, of course, was absolutely accurate; Maryland tort law did, soon thereafter, embrace the sophisticated intermediary defense to exculpate the defendant in such remote supplier situations. See, e.g., Kennedy v. Mobay Corp., 84 Md. App. 397 (1990) (applying sophisticated user defense to bar claims against manufacturers of toluene diisocyanate), aff’d, 325 Md. 385 (1992); Higgins v. E.I. DuPont de Nemours, Inc., 671 F. Supp. 1055 (D. Md. 1987) (Maryland law; holding that manufacturer of paint was in better position than bulk supplier to communicate warnings to customers’ employees), aff’d, 863 F.2d 1162 (4th Cir. 1988). The principle invoked to excuse plaintiff from reading the warning label also works to exculpate the defendant when that warning label is otherwise adequate, or when the intermediary knows of the hazard in any event.

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