The Federal Court of Appeals for the Seventh Circuit recently joined the 6th and 9th Circuits in holding that a plaintiff seeking recovery for harm from carcinogen exposure must demonstrate that the exposure was a “substantial contributing factor” to the injury. The opinion notes that cancer causation “is dosage dependent—that is, the risk of contracting lung cancer from asbestos depends on the length of time of exposure and the amount of exposure. To determine whether any exposure constitutes a substantial contributing factor, therefore, one would have to understand the timing and amount of exposure.” The court rejected arguments that de minimis exposures are compensable, holding that the “any exposure” theory “ignored fundamental principles of toxicology that illnesses like cancer are dose dependent.” The court also rejected a cumulative exposure theory, under which “every minute of exposure adds to the cumulative exposure and thus becomes a substantial contributing factor,” finding that such an approach is “merely more of the same.”
While these are toxic tort cases, the opinions may be relevant to regulatory consideration of similar issues. For example, EPA must consider exposure in regulating new and existing products under the 2016 TSCA Amendments. Exposure also must be considered in making the “substantial risk” determination under TSCA Section 8(e). These opinions suggest that the courts will take a hard look at exposure data in these and other similar regulatory contexts. The case is Krik v. Exxon Mobile Corp., 7th Cir. No. 15-3112 (decided August 31, 2017).