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Published in Michigan Environmental Law Journal, Fall 2017, Vol. 35, No. 2, Issue 103 [view full issue].
Cite: 35 Mich Env Law J 2 (2017)

Key to Causation: The Use of Expert Witnesses in Toxic Tort Cases

by John Pirich, Partner, Honigman Miller Schwartz and Cohn LLP

On July 25, 2017, the Michigan Supreme Court overturned the Court of Appeals and reinstated the Calhoun Circuit Court's order granting the defendant's motion for summary judgment in Lowery v. Enbridge Energy, L.P.[1] It was not the order itself but, rather, Chief Justice Markman's concurrence that holds particular significance. Chief Justice Markman's concurrence, which was joined by Justices Zahra and Wilder, indicates that, in toxic tort cases, "a plaintiff will often be hard-pressed to satisfy that evidentiary burden absent expert testimony"[2] and provides explicit guidance on the largely unsettled area of expert testimony in Michigan toxic tort law.

An Oil Spill and an Avulsion Lead to a lot of Legal Questions

Energy Limited Partnership and Enbridge Energy Partners, LP, (Enbridge) spilled 840,000 gallons of crude oil, which made its way into nearby waterways and spread almost 40 miles throughout the counties of Calhoun and Kalamazoo.[3] The plaintiff, Chance Lowery, lived near the origin of the spill and the waterways through which the oil disseminated.[4] Lowery alleged that, after inhaling the chemicals from the spill, he experienced coughing and vomiting, which led to hospitalization and, ultimately, a stomach hemorrhage.[5] Lowery then filed a complaint alleging that Enbridge's negligence, in exposing him to a toxic substance, served as the proximate cause of his injuries.[6]

Although Lowery presented testimony from a general physician and a treating physician, neither one could reasonably link Lowery's symptoms to the oil spill.[7] The trial court determined that there was no clear link between the stomach hemorrhage and the oil spill and granted the defendant's motion for summary judgment on that issue, but permitted Lowery to argue that his migraines and vomiting had been caused by the spill. Lowery's counsel then requested that the court grant summary disposition in its entirety, because the entire case was about the surgery to repair the stomach hemorrhage, and his counsel wished to appeal the case immediately.[8] The trial court concurred and granted summary disposition in its entirety.[9] Lowery then appealed.

The Court of Appeals reversed the grant of summary disposition. It held that no expert testimony was required to show that the toxin from the oil spill was capable of causing and did actually cause Lowery's injuries.[10] In fact, the Court of Appeals determined that the circumstantial evidence Lowery presented was sufficient for a reasonable jury to conclude that the fumes from the oil spill caused his vomiting and, ultimately, his stomach hemorrhage.[11]

Enbridge then filed an Application for Leave to Appeal with the Michigan Supreme Court. The Court granted leave to appeal to consider: "(1) whether the plaintiff in this toxic tort case sufficiently established causation to avoid summary disposition under MCR 2.116(C)(10); and (2) whether the plaintiff was required to present expert witness testimony regarding general and specific causation."[12] The Michigan Supreme Court heard the appeal and concluded that Lowery's evidence reflected "post hoc reasoning," rather than a "logical sequence of cause and effect."[13] This holding was further illuminated by Chief Justice Markman's concurrence, indicating that the "plaintiff failed to present adequate evidence of cause in fact, specifically evidence establishing either general or specific causation."[14]

But For is Bifurcated

In his concurrence, Chief Justice Markman explains the standard for causation in typical negligence tort cases and the special considerations for toxic tort claims. In order to prove that Enbridge's breach of duty[15] was the cause of his injuries, Lowery must show that "but for" Enbridge's negligence, he would not have suffered his injuries.[16] Because Lowery was making a toxic tort claim, he needed to demonstrate "an injury arising from exposure to a toxic substance."[17] Since toxic tort claims require this specialized showing of causation, many jurisdictions take a bifurcated approach by dividing causation into an analysis of general causation and specific causation.[18]

General causation relates to whether a toxin can cause the alleged harm.[19] The presence of a toxin alone would have been insufficient to show general causation. Lowery needed to demonstrate that he was exposed to the toxin and that the exposure level was high enough to cause his symptoms.[20] Evidence of the exposure level of a toxin required to cause harm is essential, because some substances are only harmful at higher levels.[21] As such, when addressing general causation, Lowery needed to tailor his evidence to the "estimated amount and duration of exposure at issue" to allow the fact-finder to reasonably conclude that both the amount of the toxin and the duration of exposure to the toxin is capable of causing the alleged injury.[22]

In contrast, specific causation "consists of proof that exposure to the toxin more likely than not caused the plaintiff's injuries."[23] In addition to providing evidence of the plaintiff's exposure levels, the plaintiff must also eliminate other "reasonable potential causes."[24] This evidence of exposure need not be mathematically precise; it can be established through reliable circumstantial evidence.[25] If used, this circumstantial evidence must enable the fact-finder to make reasonable inferences to effectively demonstrate causation.[26] The other crucial component in this framework is the "need by some reasonable means to evaluate and eliminate other reasonably relevant potential causes of the plaintiff's injury."[27] That is to say the plaintiff must be able to identify the most probable of these potential causes in order to meet the specific causation burden.[28]

Let the Experts Handle it

Lowery's supposed expert,[29] a general physician who is board certified in family medicine,[30] was ill-equipped to testify to the relevant factors in showing causation.[31] Although Plaintiff's expert did not physically examine the patient, he believed that Lowery's symptoms were the result of inhaling fumes from the oil spill.[32]

Plaintiff's expert did not testify to the exposure levels or the length of exposure necessary to cause Lowery's symptoms, thereby failing to meet the general causation standard.[33] He was not able to show that Lowery was exposed to toxins from the oil spill. Plaintiff's expert failed to eliminate other potential causes of his symptoms, and he failed to establish a causal link between Lowery's early symptoms and the stomach hemorrhage, which surely required expert testimony.[34] Even assuming that the testimony of this "expert" was admissible, Chief Justice Markman opined that Lowery would have failed to meet his burdens for general and specific causation.[35]

While the Michigan Supreme Court need not have fully addressed the issue of expert testimony to demonstrate causation because there was expert testimony in Lowery, Chief Justice Markman nevertheless addressed the issue of whether expert testimony is required in toxic tort cases.[36] He explicitly states, "expert testimony on causation is necessary in a toxic tort cases when the legal proposition is beyond the common knowledge of an ordinary juror."[37] As in the present case, it is essential to have a qualified expert witness when there are questions of science and medicine. In order to meet his burden, Lowery needed a qualified expert to help inform the jury of the specific knowledge needed to establish causation in his case.

Is Any of This New and What Does it All Mean?

While Chief Justice Markman's concurrence and the Michigan Supreme Court's decision are certainly helpful in clarifying toxic tort law, the holding in Lowery is not a departure from existing Michigan legal principles. There is little Michigan case law on the use of expert testimony in toxic court cases. One previous case on the subject, Genna v. Jackson,[38] which was heavily relied upon by the Michigan Court of Appeals in its decision, "decline[d] to adopt a per se rule requiring expert testimony in toxic tort cases."[39] Chief Justice Markman noted in his concurrence that he would "explicitly reject" interpreting the holding of Genna to mean that expert testimony is never required in toxic tort cases.[40] Genna involved "massitvely high levels of . . . mold toxins" and expert testimony regarding the deleterious health effects of mold.[41] Furthermore, the unique facts of that case make it easily distinguishable from most toxic tort cases. Unlike in Genna,[42] most toxic tort cases usually involve difficult questions of science and medicine that are beyond the common understanding of an ordinary juror.[43] As such, the Chief Justice Markman concurrence in the present case serves to clarify the need for expert witnesses in most toxic tort cases.

The decision in Lowery is consistent with other principles of Michigan law as well. In cases like Lowery, which involve questions of "complex science and the relationship between a triggering event and an alleged injury is outside of a lay juror's common knowledge,"[44] Michigan law has always required expert testimony. For example, medical malpractice cases and cases where causation inquiries are scientific in nature require expert testimony.[45] In Lowery, since the alleged cause and evolution of Lowery's symptoms were rooted in medicine, it follows logically that the court would require expert testimony to assist the finder of fact.

Lowery is also consistent with case law from other jurisdictions that requires expert testimony in toxic tort cases. For instance, the U.S. Court of Appeals for the Sixth Circuit required expert testimony to show both general and specific causation in toxic tort cases "because of the complex scientific assessments required."[46]

Looking to the future, Lowery will strike a positive balance between accessibility for plaintiffs and protection for defendants. Requiring expert testimony will continue to protect those plaintiffs who can sufficiently establish causation between a defendant's conduct and the harm suffered, while protecting defendants from tort claims with tenuous causation. Chief Justice Markman's concurrence in Lowery establishes a clear requirement for presenting expert testimony in toxic tort cases and provides timely guidance in Michigan toxic tort jurisprudence and in future litigation such as pending Flint water cases. These cases will likely involve scientific and medical queries about the link between lead levels in the Flint water supply and the plaintiffs' various alleged injuries.

[1] Lowery v Enbridge Energy L.P., 500 Mich 1034; 898 NW2d 906 (2017).

[2] Id. at 918 (Markman, C. J., concurring).

[3] Id. at 908.

[4] Id.

[5] Id.

[6] Id.

[7] Id. at 908-909.

[8] Id. at 909.

[9] Id.

[10] Id.

[11] Id.

[12] Id. at 910 (quoting Lowery v Enbridge Energy Ltd Partnership, 499 Mich 886 (2016)).

[13] Id. at 907.

[14] Id. (MARKMAN, C.J., concurring) (emphasis in original).

[15] The trial court granted summary disposition on this issue. Id. at 908, n. 3.

[16] Id. at 924.

[17] Id. at 910.

[18] Id. at 911.

[19] Id. at 913.

[20] Id. at 914.

[21] Id.

[22] Id.

[23] Id. (emphasis in original).

[24] Id. at 919.

[25] Id. at 915.

[26] Id.

[27] Id. at 916-917.

[28] Id. at 917.

[29] It is unlikely that Lowery's "experts" would have qualified as true experts under Michigan law. See Amicus Curiae Brief of Michigan Chamber of Commerce at *20-21, Lowery v Enbridge Energy L.P., 2017 Mich LEXIS 1409 (No. 151600).

[30] Lowery, 898 NW2d at 908 (MARKMAN, C.J. concurring).

[31] Dr. Koziarski, the general and vascular surgeon who repaired Lowery's stomach hemorrhage, declined to testify as to the cause of Lowery's injury. Id. at 909.

[32] Id. at 909.

[33] Id. at 919-920.

[34] Id. at 923.

[35] Id. at 920, n. 20.

[36] Id. at 917-918.

[37] Id. at 907.

[38] Genna v Jackson, 286 Mich App 413 (2009).

[39] Id. at 418.

[40] Lowery, 898 NW2d at 919, n. 18.

[41] 286 Mich App at 420-421.

[42] In Genna, no expert testimony was needed, because there was a "sufficient logical sequence of cause and effect on which a jury could conclude that Defendants' leak could have caused Plaintiffs' injuries." Brief of Michigan Chamber of Commerce at *2, 2017 Mich LEXIS 1409 (No. 151600).

[43] Brief of Michigan Chamber of Commerce at *1, 2017 Mich LEXIS 1409 (No. 151600).

[44] Id. at *4.

[45] Id.

[46] Pluck v BP Oil Pipeline Co., 640 F 3d 671, 677 (CA 6, 2011).