The highest court in Georgia recently excluded a standard plaintiff argument that “every exposure” to asbestos causes mesothelioma. In Scapa Dryer Fabrics, Inc. v. Knight, the court overturned a plaintiff verdict and reversed both the trial court and intermediate appellate court, holding that a medical expert’s opinion that “every exposure above background contributed to cause plaintiff’s mesothelioma” is legally unsound and “does not ‘fit’ the legal standard for causation”, which requires that an exposure be more than de minimis or trivial. The Georgia Supreme Court reversed, resulting in judgment for the defendant.

The defendant, a textile manufacturer in the late 60’s and early 70’s, produced dryer felts. Some felts contained asbestos that was released into the air during manufacture, at a facility where some of the pipes were insulated with material containing asbestos. Plaintiff was an outside sheet-metal contractor who worked at defendant’s facility on multiple occasions over a four-year period. Plaintiff was sometimes present when the manufacturing process was underway, worked in ventilation ducts that had collected dust, and on one occasion cut into pipe insulation and breathed that dust.

Over defendant’s objection, the trial court allowed plaintiffs’ expert pathologist, Dr. Jerrold Abraham, to testify to the following syllogism: “background asbestos is not known to cause mesothelioma;” “the precise point at which cumulative exposure is sufficient to cause any particular person to develop mesothelioma is not scientifically knowable;” “when a person has mesothelioma, it can only be attributed to his cumulative exposure as a whole;” “each and every exposure to respirable asbestos in excess of the background contributes to the cumulative exposure;” therefore, “each exposure in excess of background is a contributing cause of the resulting mesothelioma, regardless of the extent of each exposure.” Dr. Abraham went so far as to testify that “a causal connection would be lacking only if ‘there was no asbestos exposure’ attributable to [defendant]’, that “one fiber [of asbestos] above ambient levels would be causative for someone who had mesothelioma”, that “he did not need to determine the extent of [plaintiff’s] exposure, but only need to know that the exposure was more than ‘zero’”, and that “if someone gets the disease from a trivial exposure, it is still asbestos-related.’”

This is a common position taken by plaintiffs’ experts in toxic tort litigation. It is known by many names: “single fiber,” “any exposure,” “every exposure” or, in this case, the “cumulative exposure” theory of causation. The theory has been rejected by the supreme courts of Pennsylvania and Texas and many other courts; a recent California appellate court, in dicta, refused to reject this theory outright, but affirmed the plaintiff’s burden as requiring proof that the defendant’s product “was a substantial factor in contributing to the risk of developing asbestos-related cancer.” (See our earlier post on the California case.)

The jury in Scapa assessed 40% fault to the defendant and awarded plaintiffs $4 million.

The Supreme Court of Georgia analyzed this issue first by examining the relevant standards for admissibility of expert testimony. It noted that the question of admissibility of expert testimony is a question “committed to the sound discretion of the trial court.” However, using language much like the United States Supreme Court in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 597 (1999), the court held that it is incumbent upon the trial court to “act as a ‘gatekeeper’ to ensure the relevance and reliability of expert testimony.” Dr. Abraham’s qualifications were not in dispute. Instead, the defendant challenged his “single fiber” theory as “junk science”, and also argued that the testimony was not relevant because it did not “fit” the legal standard for causation under Georgia law. The court agreed with the second point (and hence did not reach the question whether the “cumulative exposure” theory is scientifically valid), holding that because this opinion “does not ‘fit’” the legal standard for causation, and for that reason, the admission of his testimony … was not helpful to the jury and amounted to an abuse of discretion.”

To prove causation in an asbestos personal injury case under Georgia law, a plaintiff must therefore show that an exposure was a “contributing factor” in bringing about the disease. It need not be “substantial”, but it must be “meaningful” and not “de minimis.”

Though the court recognized that the plaintiffs in that case “may well have presented evidence of more than a de minimis exposure” at defendants’ facility, defendants presented evidence to the contrary. But by admitting the opinion of Dr. Abraham that “any asbestos above background … was a contributing cause of the mesothelioma” (i.e., even a de minimis exposure), the trial court allowed the jury to resolve this dispute in a manner inconsistent with Georgia law.

The court cautioned: “That is not to say that expert testimony premised upon a cumulative exposure theory could never be relevant to causation.” But the court held fast to the notion that de minimis or trivial exposures are not causative. Had Dr. Abraham also presented reliable evidence that the exposures in question were “more than de minimis,” and had he based his ultimate causation opinion on exposures that were more than de minimis, “the opinion then might ‘fit’ the pertinent causation inquiry, notwithstanding that the extent of exposure is disputed.” The court pointed out that in other cases Dr. Abraham’s “cumulative exposure” theory has been allowed when coupled with a review of the evidence of the extent of exposure and of studies showing such exposures present an increased risk of developing mesothelioma.

While a precise quantitative exposure analysis is not required, a qualitative assessment is. Thus, an opinion that a “de minimis” or “any” exposure could cause mesothelioma is inadmissible (at least in Georgia), while an opinion that each “significant” or “sustained” exposure to asbestos” is a cause would be admissible.