Proving causation is a core element of any tort case. An individual cannot be sued for another’s injury if he played no role in the injury occurring. But this concept becomes much more complex in the context of a toxic-tort case. The medical conditions allegedly caused by exposure to toxic substances can take decades to manifest themselves. And once a disease is present, proving what “caused” it is rarely simple. A tumor, for example, is likely caused by many factors, which can include inherited genetic conditions, diet, environmental exposures, viral infections, radiation, carcinogenic substances—or even simple chance.
Allow me to spoil the ending of Murder on the Orient Express: They all did it. Each of the twelve suspects snuck into the victim’s cabin and stabbed him in the chest while he was deeply sedated. Yet while no one suspect was a “but for” cause of the death, each was culpable: he or she was a “substantial factor” in the wrongful death. In other words, there were twelve people who were “a material element and a substantial factor in bringing the event [the injury] about.” Turcios v. DeBruler Co., 2015 IL 117962, ¶23.
That same “substantial factor” causation principle carries over into toxic tort cases. But to establish their cases, plaintiffs typically need to proffer “experts” in medicine, toxicology, epidemiology and the environmental fate and transport of chemicals to establish liability. Two key questions are whether the plaintiff was exposed to the toxin in question and whether the dose was sufficient to cause the disease. In the past, many expert witnesses, particularly in the asbestos context, took extreme positions on exposure and dose, even arguing that exposure to a “single fiber” of asbestos was capable of causing mesothelioma, thus making even de minimis contact a “substantial factor.” Building on this concept, plaintiff attorneys and their experts also developed the “cumulative exposure” theory, claiming that cumulative exposures to multiple defendants’ fibers established proximate cause, thereby ensnaring multiple defendants at once.
It is an uphill battle for defendants when a jury is told by an expert that every exposure to a toxin a cause and that cumulative exposures to a toxin in small amounts cause disease. Although toxic tort cases in many states require the plaintiff to quantify their level of exposure (i.e. their “dose”) to prove their case, Illinois case law has been an outlier. See Donaldson v. C. Illinois Pub. Serv. Co., 199 Ill. 2d 63, 91 (2002), abrogated on other grounds by in re Commitment of Simons, 213 Ill. 2d 523 (2004) (expert allowed to testify that coal-tar emissions could have caused plaintiffs’ brain tumors, even though no study had established the exposure levels required for the pollutants to provoke tumors, no specific exposure was shown and plaintiffs did not quantify dosage).
As a result, Illinois has been an attractive jurisdiction for toxic tort cases, especially asbestos cases. Illinois law has historically endorsed the “single fiber” or “any exposure” theory, allowing the plaintiffs to avoid the burden of showing specific exposures and dose levels.
In addition, Illinois’ courts have generally applied a more lenient evidentiary standard for the admissibility of expert testimony (the Frye standard) than that applied by federal courts (which apply the Daubert standard). The Frye standard dictates that “scientific evidence is admissible at trial only if the methodology or scientific principle upon which the opinion is based is ‘sufficiently established to have gained general acceptance in the particular field in which it belongs.’’ In re Commitment of Simons, 213 Ill. 2d 523, 529-30 (2004). Under this standard, an opinion can be “accepted,” even if only a small minority of the scientific field actually agrees with it.
In Thacker v. UNR Industries, the Illinois Supreme Court held that expert testimony can be used to establish proximate causation under the “frequency, regularity, and proximity” test, which asks whether the plaintiff’s exposure to defendant’s toxic substances occurred often enough over a long enough period of time for the exposures to have been a “substantial factor” in the plaintiff’s illness. 151 Ill. 2d 343 If Illinois courts continue to allow this loose expert testimony to proceed to the jury, the “frequency, regularity, and proximity” test will quickly resemble the “every exposure” standard, because quantity or dose is still not part of the equation.
But in 2018, the Seventh Circuit arguably re-shaped toxic tort law in Illinois, affirming a lower court’s analysis that rejected vague and speculative expert testimony. Krik v. Exxon Mobil Corp., 870 F.3d 669, 677 (7th Cir. 2017). There, the plaintiff’s expert had relied upon the cumulative exposure theory and opined that “every minute of exposure adds to the cumulative exposure and thus becomes a substantial contributing factor.” Id. at 675. The Seventh Circuit rebuffed this theory, holding that “substantial exposure that cannot be attributed to a particular defendant” is insufficient and takes the “substantial” requirement out of the substantial contributing factor test. Id. The Court elaborated:
The principle behind the “each and every exposure” theory and the cumulative exposure theory is the same—that it is impossible to determine which particular exposure to carcinogens, if any, caused an illness. In other words, just like “each and every exposure,” the cumulative exposure theory does not rely upon any particular dose or exposure to asbestos, but rather all exposures contribute to a cumulative dose. The ultimate burden of proof on the element of causation, however, remains with the plaintiff. Shelton v. Old Ben Coal Co., 933 F.2d 504, 508 (7th Cir. 1991); Nolan v. Weil–McClain, 233 Ill.2d 416, 435 (2009). Requiring a defendant to exclude a potential cause of the illness, therefore, improperly shifts the burden to the defendants to disprove causation and nullifies the requirements of the “substantial factor” test.
Id. at 677. The Court pointed out that “more than thirty other federal courts and state courts have held that this cumulative/ ‘any exposure’ theory is not reliable.” Id.
Although only one Illinois Appellate Court has analyzed the Seventh Circuit’s decision in Krik so far, that court as well as others appear to be following the trend and tightening up the requirements for admissible expert testimony. The one court to address it directly, Daniels v. John Crane, Inc., distinguished Krik on its facts, holding that the experts in Daniels did not rely solely on a “cumulative exposure” theory or testify, “as did the expert in Krik, that even a de minimis exposure to asbestos could cause an asbestos-related disease.” Daniels, 2019 IL App (1st) 190170, ¶41. Further, the court found that the Daniels plaintiff “did establish the dose of asbestos fibers plaintiff was exposed to from the John Crane products,” which ranged from 0.5 to 1 fibers per cubic centimeter for one task and from 0.5 to 2 fibers per cubic centimeter for another. Thus, Daniels seems to have reintroduced the concept of dose into Illinois toxic tort cases.
A more recent Illinois Appellate Court case not only followed this trend, but added to it. In Krumwiede v. Tremco, Inc., the Illinois Appellate Court granted judgment n.o.v. for the defendants. 2020 IL App (4th) 180434. Like the lower and appellate court in Krik, the Krumwiede court spurned the cumulative exposure theory when applied to exposures from multiple defendants. It held that proximate cause demands that plaintiff’s expert opine that “exposure to asbestos from [defendant’s] products was a ‘substantial’ factor in decedent’s development of his disease, particularly when compared to his exposure to asbestos from other sources.” Id. at ¶81. In other words, Krumwiede rejected the cumulative exposure theory altogether, making the causation analysis defendant-specific.
To support this shift, Krumwiede turned to another Fourth District case that had similarly granted judgment n.o.v. in an asbestos matter, McKinney v. Hobart Bros. Co., 2018 IL App (4th) 170333, ¶77. McKinney is likely the first Illinois Appellate Court case to take a hard look at Thacker and apply some heightened scrutiny. In McKinney, the court distinguished Thacker, pointing out that Thacker involved bags of raw asbestos as opposed to the encapsulated asbestos at issue in McKinney. As a result, the court found that the release of respirable fibers was more likely to occur with bags of asbestos, and so proof of close contact to an encapsulated asbestos-containing product alone did not demonstrate substantial factor causation. In fact, the court likened such evidence as nothing “more than proving [the plaintiff] routinely walked on floor tiles containing asbestos.” Id. According to the McKinney court, a plaintiff must prove that he actually inhaled respirable asbestos fibers from the defendants’ product and that he inhaled enough of them so that he could meaningfully say the products “were a ‘substantial factor’” in causing his mesothelioma. Id. at ¶83.
This quartet of cases, Krik, Daniels, Krumwiede and McKinney, suggests that Illinois courts are quietly rejecting the universal application of Thacker. Rather, the courts are looking more closely at the facts and the science to see whether exposure attributable to the defendant could and actually did occur and, if so, whether it occurred at a level sufficient to cause disease. An “every exposure” or “cumulative exposure” argument should no longer bypass strict examination by the court. This is particularly helpful in multiple defendant cases. It appears court will require plaintiffs to independently show that the dose received from each defendant could have caused their disease. This trend re-establishes the need for scientific examination of the evidence for exposure and dose and pushes Illinois back to appropriate standards of liability.