On November 10, 2022, Kenneth and Phyllis Zerr perished in a house fire. Plaintiffs—the Zerrs’ children and Kenneth Zerr’s estate—alleged that the fire was caused by a defective dehumidifier produced by Gree.
In support of their defense, Defendants planned to use expert witnesses. On the origin of the fire, Defendants offered Todd Soong. On the potential electrical causes of the fire, Defendants offered Arash Hajjim. Lastly, on fire dynamics, patterns, and potential causes of the fire, Defendants offered Carlos Fernandez-Pello. Together, the experts purport to establish that the cause of the fire remains undeterminable. Plaintiffs sought the exclusion of three defense experts.
Plaintiffs have also produced Roy Deppa as an expert on the topic of Consumer Product Safety Commission (CPSC) regulations and procedures for the purpose of establishing that Defendants failed to timely report dangerous defects in their dehumidifiers. Defendants sought the exclusion of Deppa.
Fire Investigation Expert Witness
James Todd Soong is a certified fire investigator (CFI) by the International Association of Arson Investigators (IAAI) and a certified fire and explosion investigator (CFEI) by the National Association of Fire Investigators (NAFI). He has in excess of 10 years of experience.
Electrical Engineering Expert Witness
Arash Hajjam is a forensic electrical engineer and has in excess of 15 years of experience.
Thermodynamics Expert Witness
Dr. Carlos A. Fernandez-Pello is a Distinguished Professor of the Graduate School in Mechanical Engineering, at the University of California, Berkeley, USA. His work involves applying fire thermodynamics and combustion principles to analyze various aspects of fire and combustion processes, ranging from laboratory-scale solid fuel combustion to wildland fire dynamics.
Product Safety Expert Witness
Roy W. Deppa has over 40 years of experience in product safety, including 27 years in various positions at the Consumer Product Safety Commission. This experience gave him extensive knowledge of the agency’s regulations, processes, and procedures, as well as industry standards.
He is a registered Professional Engineer licensed in the State of Maryland.
Discussion by the Court
I. Todd Soong
Defendants retained Soong to determine the origin of the fire and its potential causes. Plaintiffs argued that Soong’s opinions must be excluded because they are based on incomplete and inaccurate information and they are not the product of reliable principles and methods.
A. Soong’s opinions on the origin and cause of the fire are admissible
Soong followed the methods prescribed by NFPA 921 in determining that the fire originated in the home’s utility room and that the cause of the fire could not be definitively determined. He performed an inspection of the building, observing fire damage levels and patterns.
Plaintiffs argued that Soong’s opinions are unreliable because he did not conduct his own testing; he uses “ambiguous words such as ‘possible,’ ‘may,’ and ‘can’”; and he developed his opinions with cherry-picked facts and confirmation bias.
However, the Court found that Soong’s method of determining the origin and potential causes of the fire—relying on observations of physical evidence, scientific principles, experience, and the opinions of Defendants’ other expert witnesses—is consistent with NFPA 921 and sufficient to satisfy Rule 702.
NFPA 921 advises that investigators should seek assistance when they “lack expertise to properly attribute meaning to a piece of data” and should utilize the “special talents or training” of other individuals in the fields of “electrical, heating and air conditioning, and other engineering fields” when needed. And NFPA 921 specifically instructs investigators to utilize words like “probable” and “possible” to denote the appropriate level of certainty.
B. Soong’s opinion relating to spoliation is inadmissible
Plaintiffs also argued that “Soong improperly claimed spoliation of evidence” under NFPA 921, which defines spoliation as “loss, destruction, or material alteration of an object or document that is evidence or potential evidence in a legal proceeding by one who has the responsibility for its preservation.”
The Court found that Soong is not qualified to opine on whether anything he observed was a result of “spoliation” or some other cause.
II. Arash Hajjam
Plaintiffs argued that Hajjam’s opinions must be excluded because he failed to follow the methodology outlined in NFPA 921.
However, Hajjam followed NFPA 921’s prescribed method for fire cause determination. His report relied on two joint site examinations, two lab inspections, the expert reports of the other fire investigation experts proffered in this case, and several other photographs and documents, including NFPA 921.
Based on his observations of the scene and analysis of the artifacts, Hajjam identified three potential causes of the fire—the dehumidifier, the branch circuit wiring in the ceiling, and a nearby light fixture—and examined each in a laboratory. Hajjam then evaluated each potential cause and ultimately concluded that “given the extensive damage and the presence of missing artifacts, multiple potential ignition sources remain, preventing a definitive conclusion regarding the exact ignition source of the fire.” The Court found that Plaintiffs’ arguments regarding the sufficiency of Hajjam’s testing and his alleged consideration of improper evidence are insufficient, in this case, to undermine the admissibility of his testimony.
III. Carlos Fernandez-Pello
Defendants offered Fernandez-Pello to discuss “potential causes and contributing factors to the fire and the possibility of the subject Dehumidifier and other potential ignition sources causing the fire.” Specifically, he was expected to provide testimony that the cause of the fire is indeterminate as per NFPA 921.
Fernandez-Pello’s opinions followed NFPA 921’s prescribed method for fire cause determination. Moreover, Fernandez-Pello discussed the fire patterns surrounding the dehumidifier, the results of the dehumidifier tests, and generated computer simulations.
Plaintiffs argued that Fernandez-Pello’s opinions should be excluded because (1) he failed to consider the presence of additional fuel loads in the vicinity of the dehumidifier; and (2) he failed to conduct testing regarding internal arcing in the dehumidifier. Those arguments fail. Although Fernandez-Pello initially testified that he was not aware of several plastic buckets near the dehumidifier, he later submitted errata indicating that he had reviewed photographs of the buckets, “concluded that the buckets didn’t burn, only melted,” and “thus, there was no need to investigate the issue anymore.”
Such inconsistency in Fernandez-Pello’s testimony on different occasions may be relevant to his credibility as a witness, but it does not undermine its admissibility altogether. And given Fernandez-Pello’s position that the dehumidifier could not have been the cause of the fire, regardless of how it ignited, the fact that he did not do additional testing to determine whether there was internal arcing did not undermine the credibility of his opinion.
IV. Roy Deppa
Defendants argued that Deppa’s testimony should be excluded because (1) Deppa is unqualified, as a professional engineer, to opine on the interpretation of federal regulations or Defendants’ state of mind; (2) his opinions concerning the process by which companies issue recalls and Defendants’ state of mind lack scientific methodology; (3) his opinions improperly relate only to punitive damages; and (4) his opinions, even if admissible, are barred under Federal Rule of Evidence 403, as his “interpretation of federal regulations and Defendants’ obligations under them would run the risk of creating a danger of overriding the Court’s jury instructions on the same” and his opinions concerning the severity of Defendants’ failure to recall risked interfering with the jury’s duty to evaluate liability.
Analysis
As an initial matter, the Court found that Deppa’s proposed testimony relating to Defendants’ state of mind is improper. Moreover, Deppa may not offer his opinion about whether Defendants’ conduct violated applicable regulations because the the law is clear that expert witnesses may not opine as to whether a party violated a given regulation.
The Court also shared Defendants’ concern that Deppa’s report included qualitative characterizations of Defendants’ conduct unconnected to any specific industry standard, and that such characterizations invade the province of the jury, who will be tasked with determining if Defendants’ conduct “showed complete indifference to or conscious disregard for the safety of others.”
In spite of that, the Court concluded that Deppa, based on his professional experience, is qualified and permitted to testify about (1) the industry standards relating to CPSC recalls, including references to relevant regulations, so long as he does not opine on whether Defendants’ conduct actually violated any regulations; and (2) Defendants’ conduct in response to the product defect that Plaintiffs allege is at the heart of this case, including the effects of those actions on the availability of the defective product.
Held
- The Court denied Plaintiffs’ motions to exclude the testimony of Arash Hajjam and Carlos Fernandez-Pello.
- The Court granted in part Plaintiffs’ motion to exclude the testimony of Todd Song.
- The Court granted in part Defendants’ motion to exclude the testimony of Roy Deppa.
Key Takeaway
Expert testimony on “the intent, motives, or states of mind of corporations, regulatory agencies and others have no basis in any relevant body of knowledge or expertise.” Thus, Deppa may not opine on what Defendants, or individuals employed by Defendants, thought or about their motivations.
Please refer to the blogs previously published about this case:
Fire Investigation Expert Was Allowed to Opine on UL Listing
Insurance Expert Not Allowed to Opine on the Actual Cash Value of the Home
Case Details:
| Case Caption: | Hillman V. Gree USA, Inc. |
| Docket Number: | 4:23cv830 |
| Court Name: | United States District Court, Missouri Eastern |
| Order Date: | May 23, 2026 |
