Types of Experts Needed for Mold Litigation

Mold exposure actions by definition involve experts from disparate fields. Assuming that a claim includes both bodily injury and property damage issues, even a relatively simple mold exposure case will require testimony from expert witnesses in the areas of medicine, construction, industrial hygiene, mycology/microbiology, and abatement. Depending on the context of the litigation, expert witnesses may also be needed to testify regarding the management of common interest developments, landlord-tenant issues, and/or insurance claims handling. See Handling Mold Litigation in California, steps 5, 7-11 (Cal CEB Action Guide Summer 2003), referred to throughout this article as "Handling Mold Litigation." Mold exposure litigation is "expert-intensive." Accordingly, the proper handling of these cases must include strategies for evaluating and challenging expert witnesses.

Underlying Science Still Developing

To begin with, some substantive knowledge of mold science is required. Mold is a biological organism, which is constantly reproducing and dying. Unlike certain chemical agents, the amount of mold in the environment cannot be calculated after exposure occurs or recreated through modeling. There are no biomarkers for exposure to mycotoxins, the toxins released under certain conditions by so-called toxic molds. Microbial contamination levels can vary greatly within a given building. Although no government standards exist to determine what level of mold is unhealthy, generally accepted guidelines have been established by the American Conference of Governmental Industrial Hygienists and the American Industrial Hygiene Association. See Handling Mold Litigation, step 11. The collection and quantification of mold samples is difficult and test results may be influenced by subjective interpretation. Newer techniques are being developed but are not yet widely used. See Handling Mold Litigation, steps 1-3, 11.

All of these scientific difficulties must be considered when evaluating the opinions of expert witnesses in mold exposure cases, e.g., was the plaintiff exposed to an elevated level of mold, did injuries result, and what were the causes of the increased fungal levels? The problems inherent in measuring mold levels, proving exposure, and determining the cause of subsequent injury can also serve as the basis for challenging expert testimony. These issues are equally important whether counsel is representing the proponent of the evidence or defending against its introduction.

Investigating Expert's Qualifications

Qualifying Standards

To qualify as an expert witness, an individual must have "special knowledge, skill, experience, training or education sufficient to qualify him as an expert on the subject to which his testimony relates." Evid C §720(a) (upon objection by any party, the expert's qualifications must be shown before he or she is allowed to testify). This foundational issue is critical in mold exposure cases because a cottage industry of mold "experts" has arisen in the last several years. Individuals who purport to hold titles such as "Certified Mold Inspectors" or "Mold Environmental Technicians" advertise that they are qualified to test and evaluate fungal levels in residential and commercial buildings. However, these "experts" often have no technical skills and no education beyond their attendance at a one- or two-day seminar that results in the granting of their "credential."

Industrial Hygienists

It is generally acknowledged that Industrial Hygienists who are board certified by the American Board of Industrial Hygiene are qualified to collect mold samples, to interpret laboratory reports analyzing the samples, and to make recommendations regarding abatement and remediation of contaminated buildings. Other individuals may also be qualified to perform these tasks, but they should have advanced degrees in the life sciences, such as microbiology or mycology, or a combination of formal education at the university level in these subjects and work experience in a laboratory or consultancy under the supervision of others holding these credentials. See also Handling Mold Litigation, steps 5, 11.

Abatement and Remediation Experts

Another area in which the evaluation of expert witnesses is difficult is the abatement and remediation of contaminated buildings. While a variety of licensed contractors and/or registered professional engineers may be qualified to investigate the causes of construction defects that lead to water intrusion and subsequent increases in fungal levels, the abatement or clean up of such sites is largely unregulated. The qualifications of an expert in this field should include being a licensed contractor who has successfully completed at least 20 prior abatement projects by obtaining "clearance" (generally defined as reducing the types and levels of mold indoors to those found in the outdoors immediately adjacent to the building). See also Handling Mold Litigation, steps 5, 7, 11, 13.

Medical Experts

The qualifications of the expert witnesses on medical issues should also be looked at critically. There are three main categories of disease or illness associated with mold exposure: (1) allergy/immunology; (2) infectious disease; and (3) toxicology. Toxicology-the study of poisons-is the most controversial; many authorities find that, at best, the link between residential exposure to mold or mycotoxins and disease is unproven. See also Handling Mold Litigation, step 10. More importantly, in evaluating medical experts it is important to consider the nature of the disease at issue. A specialist in allergy or immunology is not likely to have training or experience in toxicology. The same statement may be true regarding toxicologists and specialists in infectious disease; i.e., although both may be medical doctors (but not always, in the case of toxicologists), the fields do not necessarily overlap. The most important lesson is that anyone holding themselves out as an all purpose "mold doctor" is likely to be practicing in one or more fields in which they are not truly an expert.