Court: United States District Court for the Eastern District of Missouri, Eastern Division
Case Name: United States v. Ameren Missouri
Citation: 2019 U.S. Dist. LEXIS 51935
This case involved allegations of environmental pollution against the defendant, Ameren Missouri. The plaintiff filed suit against the defendant claiming that Ameren had violated the Clean Air Act when it underwent major renovations at its Rush Island power plant and failed to obtain permits, install pollution control technology, or meet other environmental requirements. The plaintiff offered an environmental expert witness to testify specifically on the environmental effect of mercury toxicity in the pollution from the defendant’s power plant.
The Environmental Expert Witness
The environmental expert witness was a researcher working in the field of environmental medicine. He was the head of the environmental medicine research unit at the University of Southern Denmark and an adjunct professor of environmental health at the Harvard School of Public Health. He was also the co-founder and co-editor of the Environmental Health journal and advisor to the National Health Board of Denmark. His work focused on the developmental toxicity and harmful effects of environmental chemicals.
The environmental expert witness received his MD and PhD in environmental medicine from the University of Copenhagen. His research focused on methylmercury, a type of mercury known to cause serious public health impacts and he authored more than 500 papers on the impact of chemical pollution on human health.
The environmental expert’s testimony clarified how elemental and airborne mercury emitted from power plants is transmitted through the atmosphere and converted into methylmercury. The expert opined that all airborne and elemental mercury would eventually become methylmercury, and that methylmercury can bioaccumulate in fish. The expert also noted that consuming affected fish could easily cause overexposure to methylmercury and exceed the Environmental Protection Agency’s (EPA) reference level. Further, the expert stated that about 16% of women of childbearing age in the U.S. have blood mercury concentrations higher than the recommended amount, and this can induce neurophysical and neurophysiological defects in fetuses. The plaintiff planned to use the expert’s report to argue for the defendant to establish a process called flue gas desulfurization (FGD), a method of reducing pollutant emissions at their Rush Island power plant.
In a motion to exclude the expert’s testimony, the defendant argued that it did not apply to the facts at hand and was, thus, not helpful to the trier of fact. According to the defendant, the expert offered no analysis on the reach of Rush Island’s mercury emissions and no opinion on whether any bodies of water had been contaminated. The defendant also noted that the expert testified that he did not perform an examination of adverse health effects that could result from the ingestion of fish from bodies of water near Rush Island. Furthermore, the expert had testified that he had not analyzed the possible benefits of reducing mercury emissions.
The court noted that such omissions would have been catastrophic if the plaintiff were to use the environmental expert witness to offer measurement on the specific health effects of excess mercury emissions. However, the environmental expert’s testimony was intended to explain why mercury is a dangerous pollutant in general. The court observed that the expert sought to testify that mercury gets converted into methylmercury which poses a public health hazard. Thus, the court found his opinion to be admissible.
The court also discussed the fact that the chemical speciation of toxic mercury and its general environmental hazards are not common knowledge, making the expert’s testimony helpful in determining the facts. The court also noted that pollution caused by mercury “by its nature, can seldom be adequately remedied by money damages and is often permanent or at least of long duration, i.e., irreparable,” citing Amoco Prod. Co. v. Gambell. The court, thus, believed that the plaintiff could refer to the expert’s conclusions on mercury pollution while asking for injunctive relief.
The defendant’s motion to exclude the testimony of the environmental expert witness’s testimony was denied.