On March 27, 2014, New York’s Court of Appeals issued a ruling reversing an Appellate Division decision and sustaining the lower court’s decision granting a defendant’s motion to dismiss the plaintiff’s complaint alleging personal injuries as a result of exposure to mold at the defendant’s premises.

New York’s highest court found that the plaintiff’s expert’s conclusions did not satisfy the “specific causation” requirement under the controlling Parkertest, which expanded the Frye rule. The Parker test, which established specific causation requirements of experts in toxic tort matters, involved a case that Wilson Elser attorneys successfully argued before the Court of Appeals in 2006.


In this case, Cornell v. 360 W.51st St. Realty, LLC (2014 NY Slip Op 02096), the plaintiff alleged that she was exposed to mold as a result of construction work performed in the basement of her apartment building. The plaintiff’s expert opined on studies that showed only an “association”between a mold environment and the plaintiff’s medical conditions, which included dizziness, headaches, rashes, shortness of breath, congestion and other respiratory problems.

The defendant moved for summary judgment on the grounds that the plaintiff failed to prove either that mold can cause the type of injuries that she alleged (general causation) or that mold in her apartment caused the specific injuries she alleged (specific causation).

The Court of Appeals held that a cause-and-effect relationship did not exist between exposure to indoor dampness and mold and the kinds of injuries that plaintiff alleged. The court expanded the previous ruling by the Appellate Division, First Department in a mold case that an “association” is not equivalent to “causation.” [Fraser v. 310-52 Townhouse Corp., 57 AD3d 416 (1st Dep’t 2008)]

Frye Rule and Parker Test

The Frye rule requires the trial court to determine the general acceptance of a methodology used in the relevant scientific community. In contrast to the more liberal standard for admissibility of expert testimony under the Federal Rules of Evidence and Daubert, the narrower Frye rule requires a survey of whether most scientists in the field believe it to be reliable.

In 2006, the New York Court of Appeals further narrowed Frye by establishing another requirement of “specific causation” in toxic tort cases under the Parker test (Parker v. Mobil Oil). As Parker makes clear, to demonstrate that an allegedly toxic substance caused a particular injury, there must be a valid assessment of (1) exposure, (2) general causation and (3) specific causation.

Practice Points

Expert testimony that deviates from conventional methodology has a capacity to prejudice a jury. Experts are often given great deference by jurors. Should the expert’s testimony be based on speculation rather than science, juror bias and error are unavoidable. When expert testimony involves the issue of causation in toxic tort actions, it is especially vital that the court scrutinize the expert opinion before it goes to the jury and, if necessary, preclude the expert from testifying.

This recent decision reaffirms that an assessment of specific causation is required in the scientific community and in the courts. A waiver of this requirement would call for jurors to speculate whether a plaintiff’s personal injuries claims are the result of exposure to certain alleged toxins. Where scientists cannot establish a causal connection, a jury should not be asked to do so.