New York Court of Appeals Holds “Symptom Threshold” Methodology Is Inadmissible, But Cites “Odor Threshold” Methodology With Approval
—by David M. Katz
Sean R. v. BMW of N. Am., LLC, 48 N.E.3d 937 (N.Y. 2016).
The New York Court of Appeals recently decided that the basis for an expert opinion on the specific concentration of a chemical cannot be predicated solely on a person’s symptoms, but also noted that expert opinion that a chemical was present at the concentration of scent detection could be admissible.
On February 11, 2016, the New York Court of Appeals decided Sean R. v. BMW of N. Am., LLC, 48 N.E.3d 937 (N.Y. 2016).
The plaintiff was born with significant physical and mental birth defects. The plaintiff alleged that his injuries were caused when his mother inhaled high concentrations of gasoline fumes while driving her 1989 BMW 525i during her first trimester of her pregnancy. Both the plaintiff’s mother and grandmother stated that they could smell gasoline odors in the car. Additionally, the plaintiff’s mother suffered from “headaches, dizziness and throat irritation” after driving in the car. Further, the plaintiff’s mother and father stated that they could smell gasoline in their house when the car was parked in the garage.
Two causation experts opined on the nexus between the gasoline vapor exposure, the concentration of the gasoline during the exposure, and the plaintiff’s birth defects. Using two separate methodologies, the plaintiff’s two causation experts came to the conclusion that the plaintiff’s mother inhaled gasoline at a concentration of 1,000 parts per million based solely on the symptoms exhibited during exposure to the gasoline fumes.
The defendants first filed motions for summary judgment, arguing that the plaintiff’s experts failed to lay a foundation for their opinions. The trial court denied the motions. The appellate division modified the order on other grounds.
The defendants then challenged the experts’ “symptom-threshold” methodology, arguing that using symptoms to determine a concentration of a chemical is not generally accepted within the scientific community. The trial court precluded the plaintiff’s experts from testifying because symptom-threshold methodology was not generally accepted in the scientific community as a means of determining concentrations of chemicals. On reargument, the court reaffirmed its prior decision. The appellate division affirmed and granted a motion for leave to appeal to the Court of Appeals.
The plaintiff’s experts employed the symptom-threshold methodology. Under the symptom-threshold methodology, an expert uses statements regarding odors and the symptoms that resulted to determine the concentration of chemicals that a person was exposed to. The Court of Appeals began by noting that the plaintiff could not show any scientific literature employing the symptom-threshold methodology for causation purposes. While the Court of Appeals noted that smelling chemicals and experiencing symptoms could be corroborative of a level of concentration, that evidence alone cannot “divine an otherwise unknown concentration of gasoline vapor.” Thus, the court found that a symptom-threshold methodology, where symptoms are used to determine the concentration of a chemical, was not generally accepted in the scientific community.
The Court of Appeals distinguished the symptom-threshold methodology from other cases where experts employ the “odor threshold” methodology. Similar to the methodology employed by the plaintiff’s experts, experts using the odor threshold methodology determine that a chemical concentration exists because the witness smelled a chemical. However, unlike the plaintiff’s experts, experts employing the odor threshold methodology limit their opinion to the fact that the concentration was at least at the minimum concentration required for humans to smell the chemical. The Court of Appeals noted that the odor threshold methodology is admissible because the level of detection is self-proving: if someone can smell a chemical, then it must be present at a certain minimum level. As a result, the Court of Appeals, while rejecting the symptom-threshold methodology, also opened the door for the odor threshold methodology in toxic tort cases where the level of detection is equivalent to the level of toxicity.