Expert Article Library

Toxicologist Not Allowed to Testify to Causation Because of No Physical Exam

Case Name: Marmo v. Tyson Fresh Meats, Inc., (Click here for the full text of the case)

Court: 8th Circuit Court of Appeals

Date: August 3, 2006

Expert: Toxicologist . Dr. Harriet Ammann

Issue: Whether the plaintiff’s expert could testify to causation of the plaintiff’s injury when the expert interviewed but did not examine the plaintiff and did not inquire into other toxic exposures?

Summary of case: Plaintiff sued under nuisance, strict liability and negligence claims relating to a wastewater treatment lagoon owned by Tyson Meats.

Role of the expert: Dr. Harriet Ammann was allowed to testify that the plaintiff’s injuries were “consistent with” hydrogen sulfide exposure. Dr. Ammann was not allowed to testify regarding actual medical causation.

Challenges to the Expert's testimony: Toxicologists are allowed to testify that exposure to a certain chemical is the cause of particular injuries. However, toxicologists are deemed reliable according to the circumstances of each case. Here, Dr. Ammann only interviewed, and did not examine, the plaintiff. Dr. Ammann also did not take other factors into consideration that could have also been potential causes. The Court of Appeals held that the District Court properly prohibited the expert from testifying to “causation.”

Summary prepared by M. Lanzone, Student, University of California, Hastings College of Law