Toxic Tort Defense Made Tougher by New Science and State Courts

Recent amendments to the Clean Air Act that have slashed action levels for emission controls, and scientific advances allowing for lower-level detection, means plaintiffs inevitably will attempt to use these levels as “proof” of dose in litigation. As a result, defendants must be prepared to aggressively challenge expert theories claiming that low-level or “any or every” exposure can cause disease.

When assessing personal injury cases, analyzing the dose of a substance to which plaintiffs allege exposure is critical for the defense. Defendants’ best approach to addressing this aspect of plaintiff’s case is often pre-trial exclusion of unqualified experts, deficient expert opinions based on unsupported theories, and cherry-picked evidence. Specifically, expert opinions that fail to establish either a threshold dose that can cause injury or that a plaintiff’s dose exceeded that threshold are ripe for challenge.

Any defendant devising a defensive strategy should be sure to understand the relevant jurisdictions’ substantive requirements for causation and standards for admissibility of expert testimony. Even if defendants are unsuccessful in pre-trial evidentiary challenges to plaintiffs’ proof, motion practice offers a first opportunity to educate judges on these basic principles of toxicology.

While failing to establish that a plaintiff’s dose was at or above a threshold that can cause disease should result in dismissal, some courts permit such cases to reach the jury under what has been referred to as the any-exposure theory. Plaintiffs have successfully established “any exposure” theories of causation in some jurisdictions, notably California. Other states, including New York, have rejected the any-exposure theory.

The key California case embracing the “every/any-exposure theory stems from asbestos litigation. In Davis v. Honeywell International, the plaintiff alleged that exposure to asbestos in brake linings caused her deceased father’s mesothelioma. At trial, the plaintiff’s expert said he didn’t “perform any calculations or estimates of the dose of asbestos” the plaintiff’s father “may have received from any of the activities he engaged in.”

Instead, the expert relied on “an article that found that respirable asbestos fibers come off brake linings when they are washed with distilled water, and that it’s generally accepted that if there is visible dust from a product made from asbestos, it would include a substantial amount of asbestos.” The jury reached a verdict for the plaintiff.

Honeywell appealed, contending the expert’s testimony should have been excluded. The California appellate court disagreed—finding the every-exposure theory “is the subject of legitimate scientific debate.” The appeals panel also noted that the court’s gatekeeper role for expert testimony was to exclude “clearly invalid and unreliable expert opinion.”

Having determined that any-every exposure theory was the subject of legitimate scientific debate, the testimony based on that theory was admissible. The California Supreme Court so far has declined to review intermediate appellate divisions approving of the “any/every exposure” theory.

Unlike California, New York requires a scientific expression of dose. In Parker v. Mobil Oil, a gas station attendant alleged that inhalation exposure to benzene caused him to develop leukemia. One of the plaintiff’s experts relied on a National Institute for Occupational Safety and Health study that “found a relationship between increasing cumulative benzene exposure and leukemia mortality.” The expert also cited “several studies that found an increased risk of leukemia in petroleum refinery workers.”

Another expert’s opinion offered that the plaintiff “had greater levels of exposure to benzene than the workers in the refinery studies.” Neither expert quantified nor qualitatively estimated Parker’s exposure. The defendants moved to exclude the experts’ opinions and for summary judgment, which was denied.

The defendants appealed and the case reached the New York Court of Appeals, which noted that “an opinion on causation should set forth a plaintiff’s exposure to a toxin, that the toxin is capable of causing the particular illness (general causation) and that plaintiff was exposed to sufficient levels of the toxin to cause the illness (specific causation).”

In evaluating the plaintiff’s proof, the state’s highest court noted that “precise quantification” wasn’t needed. It noted several examples of how an individual could demonstrate their dose level, including comparing “the exposure levels of subjects of other studies could be helpful provided that the expert made a specific comparison sufficient to show how the plaintiff’s exposure level related to those of the other subjects.”

What a plaintiff isn’t allowed to do is merely identify that exposure occurred and articulate that the substance is dangerous. Based on this, it affirmed dismissal of the case, rejecting proof of causation based on unquantified low levels exposure to a dangerous substance.

The appeals court’s reasoning in Parker was extended to asbestos cases in Matter of N.Y.C. Asbestos Litigation. In that case, New York’s First Department determined the theory of cumulative exposure was “irreconcilable with the rule requiring at least some quantification or means of assessing the amount, duration, and frequency of exposure to determine whether exposure was sufficient to be found a contributing cause of the disease.”

Instead, “a plaintiff claiming that a defendant is liable for causing his or her mesothelioma must still establish some scientific basis for a finding of causation attributable to the particular defendant’s product,” the mid-level appellate court said.

When litigating a dose case, attorneys should focus on challenging unqualified expert testimony, highlighting deficiencies in causation evidence, and demonstrating that plaintiffs fail to meet jurisdictional standards for proof of specific causation.

This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law and Bloomberg Tax, or its owners.

Author Information

Louis Russo is an associate with Hollingsworth’s complex litigation, pharmaceutical products, and toxic torts and products liability groups.

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