Toxicologist Excluded

In a recent decision in the Southern District of Iowa, the court excluded testimony of plaintiff's toxicologist on the issue of specific causation as unreliable. The court held that the expert engaged in ipse dixit and his opinion concluding that the mother was exposed to "enough" of a pesticide to cause her son's neurodevelopmental delay was inadmissible.

A mother and son brought claims alleging that a chlorpyrifos-containing pesticide used in the home to treat spider infestation while the mother was pregnant caused the developmental neurotoxicity of her child. While court ruled that the toxicologist was qualified to testify about general causation issues (i.e., that organophosphate pesticides acted upon the development of brain tissue and on the particular vulnerability during the prenatal and natal stages), his opinion testimony on specific causation was unreliable. Specifically, he failed to eliminate other causes that might have caused or contributed to the mother and son's symptoms; to estimate the amount of chlorpyrifos the mother inhale, ingested or absorbed; and to determine the duration of her exposure.

Click here for the Order.

Junk v. Terminix Int'l. Co. Ltd. Partnership, No. 4:05-cv-0608-JAJ (S.D. Iowa 2008)