On October 16, 2023, the California Court of Appeal for the Second Appellate District issued a landmark ruling for mold exposure cases in the matter of Brancati v. Cachuma Village, LLC. The Court reversed an order by the Santa Barbara County Superior Court which had excluded the testimony of immunologist/allergist Dr. Ronald Simon (of Scripps in San Diego) who was the Plaintiff’s medical expert. The Court ruled that Dr. Simon’s opinions were legally sound and admissible because they were “based on facts and a differential diagnosis.” The Court noted that Dr Simon examined the plaintiff and conducted a differential diagnosis, reviewed the results of environmental testing and reviewed published studies. Accordingly, the Court of Appeal held that Dr. Simon’s opinion “was based on facts, not a leap of logic” and that the trial court erred in excluding his testimony.

The decision is also extremely important because it recognized that mold poses a health hazard to those who are exposed to it and approvingly cited important literature regarding the health effects of mold. For instance, the Court recognized important scientific studies and public health documents, including position statements from the State of California Department of Public Health. The Court also cited legal rulings from other jurisdictions acknowledging “the link between exposure” to molds and “adverse health effects.”

The Brancati decision is very helpful to Plaintiff’s in cases involving mold exposure, habitability, and other cases involving exposure to organic hazards (like dust mites). The decision is also important because it was decided by the same Court that had previously decided Geffcken v. D’Andrea (2006 137 Cal.App.4^th 1298, 1311, which is often cited by the defense in mold exposure cases. In reaching their ruling, the Brancati Court distinguished their prior Geffcken decision, making clear that ruling was limited to mycotoxins and was not applicable to Dr. Simon’s testimony about health effects of mold and moldy odors/microbial volatile organic compounds. Overall, Brancati makes it very difficult, if not impossible, for the defense to challenge the admissibility of medical opinion testimony from qualified experts who conduct a reasonable differential diagnosis, based on studies/public health authorities.