Exposure to Organic Solvent Allegedly Causes Neurological Injuries

Michael Samson

Written by
— Updated on June 23, 2020

Exposure to Organic Solvent Allegedly Causes Neurological Injuries

Neurology Expert WitnessCase: Bonner v. ISP Techs., Inc., 259 F.3d 924 (8th Cir. 2001).


The plaintiff, an assembly line worker, was sprayed with organic cleaning solvent at work. As a result, she claims, she suffered from a wide variety of neurological (caused by brain damage), cognitive and psychological (caused by the initial exposure and subsequent health issues) problems, including some Parkinsonian symptoms (caused by brain damage). The plaintiff brought in two doctors, a neurologist and a toxicologist. They testified regarding the causal effects of the cleaning solvent on the plaintiff’s mental and psychological well-being. A Daubert hearing was held to determine whether or not these expert testimonies would be admissible. It was determined that they were and the plaintiff ended up receiving $2.2 million as part of the judgment.

Expert Witness Analysis

The plaintiff brought in Dr. Raymond Singer, a neurologist. Dr. Singer was permitted to testify that the plaintiff suffered from brain dysfunctions and personality disorders consistent with exposure to defendant’s solvent at toxic levels. Dr. Raymond Singer testified that exposure to solvent caused the plaintiff to suffer permanent organic brain dysfunction. It manifested itself in Parkinsonian physical symptoms, cognitive impairments, and personality disorders. He also testified that inhalation was a more potent exposure mechanism than ingestion and that he followed normal procedures for evaluating patients with potential toxic exposure.

The defendant responded that Dr. Singer’s theory was developed for litigation, not subjected to peer review, had not been published in scientific literature and was wholly unsupported by epidemiology. The defendant also said that Dr. Singer didn’t quantify plaintiff’s exposure, didn’t opine on threshold exposure necessary for injury, and failed to rule out other potential causes. In addition, he did not follow established guidelines for evaluating brain injury.

However, the district court’s role was not to determine whether Dr. Singer’s theory was correct, and the appellate court’s role is not to duplicate district court’s analysis, which correctly held that Dr. Singer’s testimony was based on sufficiently good science to go to jury. The district court conducted an exacting review of the science involved and concluded that, because the expert’s methodology was scientifically valid, the scientific questions were best addressed by allowing each side to present its experts and submit their opinions to the jury. The defendant offered no studies indicating its solvent was incapable of causing permanent damage. Defendant finally argued that Dr. Singer had no degree or academic work in toxicology, but credentials were surprisingly unchallenged.

Expert Witness Admissibility:

The admissibility was confirmed. In general, toxic tort plaintiffs must prove that the toxin is capable of causing injuries like plaintiffs’ in humans and that it did in fact cause plaintiff’s injuries.  However, the first victims of a new toxic tort shouldn’t be barred from suit simply because medical literature, which will eventually support causation, has not yet been completed.  Plaintiffs do not need to produce mathematically precise tables equating levels of exposure with levels of harm. They must offer evidence from which jurors can reasonably conclude that exposure probably caused injuries.

There is no requirement that plaintiff’s expert must always cite published studies on general causation. Nor is there a requirement that there must be pertinent epidemiological studies supporting plaintiff’s position exist. Even if the trial judge believes there are better grounds for some alternative conclusion and that there are some flaws in expert’s methods, expert’s opinion should be admitted if there exists good grounds to support it. The only question is whether the testimony is sufficiently reliable and relevant to assist the jury. Factual basis of expert opinion generally goes to credibility of the expert witness, not admissibility.

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