Martin v. Shell Oil Co.

A station owned by Shell Oil Co. (defendant) had an underground storage tank that contaminated the groundwater with components of gasoline, including methyl tertiary-butyl ether (MTBE). Data from the monitoring of wells showed that the shallow groundwater flowed toward the north-northwest of the station. Catherine Martin and Dorinda Frug­é (collectively, the homeowners) (plaintiffs) owned homes east and south of the station, respectively. The homeowners sued Shell under several theories, claiming that MTBE found in their wells was attributable to Shell and caused bad-tasting water, barren land, health problems, and a risk of cancer. To prove causation and damages, the homeowners retained (1) an environmental expert to establish that deep groundwater flowed toward the homeowners’ property, and (2) a toxicology expert to establish that MTBE caused the homeowners’ health problems. Shell filed motions in limine to exclude both experts’ testimony on the grounds that they lacked qualifications and that their testimony lacked relevance and reliability. The homeowners maintained that their experts were qualified and that their opinions were relevant and reliable. Additionally, the homeowners claimed that the burden of causation should be shifted to defendants in cases involving health harms caused by untested products, and that a plaintiff’s expert testimony on causation in such cases should be subject to lower standards of admissibility. The homeowners argued that requiring a plaintiff to prove causation is contrary to public policy because it creates a disincentive for manufacturers to test their products.