Expert Witness Profiler

Tag: Contamination

  • Veterinary Medicine Expert Allowed to Opine on Sources of Contamination

    Veterinary Medicine Expert Allowed to Opine on Sources of Contamination

    Plaintiff Kim Gentry trains riders and horses in dressage. This professional negligence case concerns the untimely death of Gentry’s beloved horse, Dantique, and Gentry’s dashed hopes to perpetuate Dantique’s bloodline.

    Plaintiff retained an equine appraiser, Tanja Schnuderl, as well as a veterinary expert, Robert Boswell. Defendants sought to exclude the testimony of both experts.

    Equine Appraisal Expert Witness

    Tanja Schnuderl is a certified appraiser with the American Society of Equine Appraisers and has established her own equine appraisal business.

    She is also the Director of International Services at The Equine Expert LLC and serves as consultant and expert witness with specialties in barn management, horse behavior and appraising.

    Get the full story on challenges to Tanja Schnuderl’s expert opinions and testimony with an in-depth Challenge Study.

    Veterinary Medicine Expert Witness

    Robert P. Boswell is a 1985 graduate of the University of Florida College of Veterinary Medicine and has devoted the entirety of his career to the practice of equine medicine and surgery with an emphasis on equine sports medicine.

    Want to know more about the challenges Robert Boswell has faced? Get the full details with our Challenge Study report.

    Discussion by the Court

    Tanja Schnuderl

    Schnuderl calculated the value of the oocytes by taking the average price of five embryos (which are fertilized oocytes), multiplying that cost by twenty, which was the number of oocytes removed from Dantique’s ovaries, and then applying a twenty percent reduction “to accommodate for the 80% success rate of embryo transfers and end up at the fair market value per oocyte.”

    Defendants’ beef is with the twenty percent reduction. They argued that this adjustment “is not based upon facts or data, and therefore not reliable.”

    Here, Defendants are not attacking the methodology Schnuderl used—in fact, they concede that “her calculation of the ‘comparable’ figures appears reasonable”—but rather the source of her twenty percent reduction.

    Because attacks on the source of an expert’s opinion go to weight and not admissibility, Defendants have not established a basis to exclude Schnuderl’s opinions as unreliable.

    Robert Boswell

    Boswell’s report stated that because “the ovary acts as an impenetrable ’tissue container’ for the oocytes,” contamination could only have occurred at the Hospital, not when the ovaries were removed. He said that contamination could result from improper cleaning and rinsing of the ovaries, and that the oocytes should have been placed in separate vials of separation media so that if one oocyte was contaminated, it would not contaminate the others.

    At Boswell’s deposition on January 16, 2026, when asked whether he could “identify a breach of the standard of care,” Boswell responded that a breach occurred at some point during the oocyte removal process. More specifically, Boswell pointed to combining all of the oocytes into one vial of separation media and a lack of proper aseptic technique as breaches of that standard. Boswell did not include this ultimate conclusion in his report because he “thought it was self-evident.”

    Analysis

    Defendants first took issue with Boswell’s testimony that Defendants breached the standard of care, arguing that this is a new opinion that was not timely disclosed in Boswell’s report. True, Boswell did not use the words “standard of care” in his report except to describe his view of the Hospital’s failure to investigate the contamination. But he did explain that contamination must have occurred at the Hospital; improper cleaning and rinsing of the ovaries could have caused it, and that the oocytes should have been placed in different maturation media. So Boswell’s deposition testimony is not a new opinion—rather, it is the same opinion reworded in response to questioning from Defendants’ counsel.

    Defendants next argue that Boswell is unqualified because he has never practiced equine reproductive medicine, nor has he fertilized embryos using these procedures. But Boswell is not testifying about the specifics of equine reproductive medicine or embryo fertilization. His opinions relate to proper aseptic technique and sources of contamination—broad principles of veterinary medicine that a veterinarian with forty years of experience is certainly qualified to testify to, even if he has not performed the specific procedure at issue.

    Defendants finally argued that Boswell’s methodology is unreliable because his opinions are based on “his own assumptions, conclusions, and anecdotes” instead of data and studies.

    Here, Boswell reaches his conclusions—on the timing of contamination, causes of contamination, and breaches of the standard of care—through his personal experience as a veterinarian combined with a review of the medical records and relevant depositions, which are reliable bases for his non-scientific opinions.

    As a result, the Court allowed both experts, Schnuderl and Boswell, to testify.

    Held

    The Court denied Defendants’ motions to strike Plaintiffs’ experts, Tanja Schnuderl and Robert P. Boswell.

    Key Takeaway

    An expert may use their experience to reach non-scientific testimony. In this case, Boswell reaches his conclusions—on the timing of contamination, causes of contamination, and breaches of the standard of care—through his personal experience as a veterinarian combined with a review of the medical records and relevant depositions.

    Case Details:

    Case Caption: Gentry V. Prell
    Docket Number: 5:25cv50
    Court Name: United States District Court, Florida Middle
    Order Date: July 02, 2026
  • Engineering Expert Allowed to Opine on Property Damage

    Engineering Expert Allowed to Opine on Property Damage

    Plaintiff R&J Components filed this action for negligence, alleging damage to inventory during roof renovations. Centimark Corporation and SIU Professional Roofing LLC (“Defendants”) sought to exclude Plaintiff’s damages expert, Mikey Minor, under Rule 702 of the Federal Rules of Evidence.

    Engineering Expert Witness

    Mikey Minor is a director of consulting and lead consulting engineer with twenty years experience with an industry-leading engineering firm servicing the insurance and legal industries on losses involving electronics,
    electrical infrastructure, and electro-mechanical equipment. He supervises the entire division of engineers in multiple locations and provides support for data, salvage, and restoration divisions.

    In addition to consulting on high-profile and large losses, he oversees assigning and reviewing all projects with engineering staff, developing ongoing test procedures and research protocol, and performing peer review and quality control of engineers’ work product.

    Get the full story on challenges to Mikey Minor’s expert opinions and testimony with an in-depth Challenge Study.

    Discussion by the Court

    Plaintiff designated Mikey Minor to testify as an expert witness on (1) the extent of the property damage and (2) the value of the loss.

    I. Qualification: Specialized Knowledge

    Defendants asserted that Minor “has no particular knowledge, training, skill, or experience that would assist the jury as to determining [the] value of the allegedly damaged inventory.”

    Plaintiff argued, “Minor has specialized knowledge in industry sources to obtain pricing and evaluat[e] unique components to develop comparison pricing where exact ‘apples to apples’ components may not exist in the market.”

    Plaintiff has demonstrated by a preponderance of the evidence that Minor’s valuations and consideration of factors including the identification of each component, its footprint, operation, and more, is beyond the knowledge of a layperson. As such, the Court held that Minor is qualified to testify to these matters.

    II. Reliability

    A. Items 1 & 7: Failure to Determine the Extent of the Damage & Subjective Evaluations of Contamination

    Defendants argued that Minor’s testimony and opinions are not reliable because he failed to determine the extent of the damage, did not identify the source of contamination in his evaluation, and made subjective evaluations of the level of contamination observed on the inventory.

    Plaintiff emphasized that Minor inspected the subject inventory on two separate visits: in May and June of 2022. In the second visit, which took place over the course of three days in June, Minor and his team visually inspected, photographed, and noted the contamination and number of parts in total inventory of approximately seventy skids containing over 500 different part numbers and parts exceeding fifteen million pieces of inventory.

    Minor has previously served as an expert and has worked on multiple high profile insurance claims to document damages and identify costs. His determination of the extent of the damage is supported by photo evidence that could be used to replicate his findings. He also created various categories of contamination to classify and evaluate the levels of damaged inventory.

    This type of visual assessment, inspection, and valuation falls squarely within Minor’s field of practical expertise. Minor sufficiently explained his methodology and bases for his determinations in categorizing and classifying the damaged inventory. The Court is satisfied that this methodology is reasonably reliable under Rule 702(c) and has been reliably applied to the facts under Rule 702(d).

    B. Item 8: Failure to Determine Fair Market Value

    Defendants argued that Minor was initially retained to determine the replacement value of the inventory, not the fair market value, and that his valuation of the goods erroneously includes only the replacement value.

    Plaintiff has explained that its water damaged products have a resale value of zero. Minor’s reliance on Plaintiff’s statements that the products are a complete loss after being damaged by water is not a basis for the exclusion of his testimony.

    Further, using this resale value, Minor’s description in his deposition of the method he used to obtain the values of the inventory describes an amount matching the description of fair market value.

    Though Defendants may raise concerns over a jury being confused or misled, the Court disagreed. Ultimately, Defendants took issue with how Minor defines his data, but such a dispute did not go to the reliability of Minor’s testimony, at least for Rule 702 purposes.

    C. Item 9: Acceptance of Plaintiff’s Allegations

    Defendants argued that Plaintiff’s expert “is unreliable because he simply accepts Plaintiff’s allegations.” As an example, Defendants highlighted that Minor accepted Plaintiff’s assertion that all skids claimed as damaged did, in fact, sustain damage.

    Minor’s reliance on Plaintiff’s list of damaged skids months after the water intrusion, as well as checking Plaintiff’s valuations on items for values—especially at the quantity Plaintiff held—that were not readily available, is reasonable and likely necessary given the circumstances. Though Defendants asserted that “Minor’s methodology was patently unreliable because he ignored market data in favor of appeasing . . . Plaintiff,” Minor’s deposition and report indicated that he used reasonable diligence to reach opinions regarding the value of Plaintiff’s damaged inventory, checking numerous websites, confirming with outside sources, and drawing on personal experience to determine values.

    Plaintiff has shown by a preponderance of the evidence that the methodology used to confirm the values for available quantities of the claimed inventory is consistent with Minor’s expertise and has been explained clearly enough to withstand judicial scrutiny.

    D. Item 10: Assignment of Value to Items Lacking Evidence of Contamination

    Defendants also asserted that Minor’s methodology and opinions are unreliable because he assigned value to items that his own investigation concluded did not show any evidence of damage or contamination.

    Plaintiff responded that Minor created various categories of contamination to provide a more thorough analysis, and that inventory subject to water and debris could not be sold by Plaintiff such that Defendants’ focus on functionality misses the mark.

    Defendants construe Plaintiff’s response as a concession that inventory with no visible contamination is still marketable. It is unclear whether Plaintiff does, in fact, concede this point given Plaintiff’s evidence indicating that any exposure to the moisture whatsoever makes the products unmarketable because a willing buyer would not be interested in buying materials that had the risk of contamination.

    In any event, this argument again goes to the weight, rather than the admissibility, of Minor’s testimony. A jury can determine whether it is reasonable for Plaintiff to be compensated, should it find liability, for products containing no visible evidence of contamination.

    E. Items 2-6: Failure to Consider Prior Sales Data or Analyze Costs of Acquisition, Potential Resale Value, Salvage Value, & Whether Inventory Was Obsolete

    Defendants list these “failures” with little, if any, explanation or reasoning provided to explain why they warrant exclusion of Minor’s testimony. The Court is not persuaded that any of these independent bases for purported unreliability are cause for the exclusion of Minor as an expert; nor would their collective effect change this determination.

    Ultimately, these independent “holes” Defendants are attempting to “poke” are all factors that appear to suggest a lack of credibility, as opposed to reliability, on the part of Plaintiff’s expert. A matter affecting the weight and credibility of the testimony is a question to be resolved by the jury.

    The Court found that Plaintiff has met its burden of showing by a preponderance of the evidence that Minor’s methods and opinions were reliable and will help a jury’s understanding or determination as to the extent of the damage and the value of the loss.

    Held

    The Court denied Defendants’ joint motion to exclude the testimony of Mikey Minor.

    Key Takeaway

    The Court need not determine that the expert testimony a litigant seeks to offer into evidence is irrefutable or certainly correct. As with all other admissible evidence, expert testimony is subject to being tested by “vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof.”

    Case Details:

    Case Caption: R&J Components Corporation V. Centimark Corporation
    Docket Number: 2:23cv358
    Court Name: United States District Court, South Carolina
    Order Date: November 18, 2025
  • Environmental Engineering Expert Witness Validates Methodology Employed by Whistleblower

    Environmental Engineering Expert Witness Validates Methodology Employed by Whistleblower

    On Feb. 3, 2023, a train carrying chemicals jumped the tracks in East Palestine, Ohio, rupturing railcars filled with hazardous materials and fueling chemical fires at the foothills of the Appalachian Mountains. The Defendant Norfolk Southern Railway Company (“NSR”) was held responsible for the train derailment and chemical spill (vinyl chloride), which adversely affected not less than 500,000 people. It necessitated immediate evacuation of all homes and businesses in an approximate one-to-two-mile radius of the Site.

    EPA’s handling of chemical testing was called into question in the wake of the derailment, which has led to serious personal and professional repercussions. As a result, multiple whistleblowers came forward to testify to the Environmental Protection Agency’s (EPA) investigation and potential manipulation of data collection regarding chemical contamination in East Palestine.

    Scott Smith, for instance, conducted multiple rounds of testing in and around East Palestine to come up with evidence of significant environmental contamination. Testimony from forensic engineer and environmental contamination expert, Stephen Petty, has validated independent data collected by Government Accountability Project client Scott Smith.

    Environmental Engineering Expert Witness

    Stephen Petty is currently President of Engineering & Environmental Services, Inc. (EES).  He also served as an Adjunct Professor at Franklin University, where he taught courses in environmental and earth sciences.  Prior to starting EES Group, Inc. in 1996, Petty was the Manager of Residential and Commercial Technology at Columbia Energy and a Senior Research Engineer at Battelle.  He has 32 years of forensic engineering, health and safety, environmental engineering, and energy experience.  

    Get the full story on challenges to Stephen Petty’s expert opinions and testimony with an in-depth Challenge Study. 

    Discussion by the Court

    Since the derailment, Smith has traveled to East Palestine 27 times and has conducted 31 rounds of testing on homes, soil, and water.  His work revealed dangerous levels of dioxins and furans in the town’s air, water, soil, and homes, which counters the EPA narrative that it is safe to live in East Palestine. 

     Some EPA staffers had dismissed Smith as a “fake scientist,” while class  counsel told the Court that misinformation has been spread about the settlement including “inaccurate commentary attributable to Scott Smith, a non-class member with no formal scientific or medical training or education.”

    Petty, an expert who previously worked for attorneys pursuing the class action settlement, submitted a declaration validating his environmental testing and sampling work. He praised Smith’s quality control and methodology as meeting professional standards.

    This new filing by Petty substantiated Smith’s credibility, pointing to the lack of human health assessment studies in East Palestine. 

    Held

    Plaintiffs’ attorneys own testing expert validated Scott Smith’s data and methodologies.

    Key Takeaway:

    Despite facing personal and professional challenges, Smith stood up for the health of the East Palestine community. He provided concrete evidence that the EPA is altering data to downplay the dangers.

    Case Details:

    Case Caption: In Re: East Palestine Train Derailment
    Docket Number: 4:23cv242
    Court: United States District Court, Ohio Northern
    Declaration Date: September 24, 2024
  • Forensic Accounting Expert Witness’ Opinion About Defendant’s Potential Contribution of APFOs Admitted

    Forensic Accounting Expert Witness’ Opinion About Defendant’s Potential Contribution of APFOs Admitted

    The case involves allegations concerning the contamination of drinking water in Hoosick Falls, New York, by perfluorooctanoic acid (PFOA), a chemical commonly referred to as PFOA. Plaintiffs claim that the primary source of this contamination was a fabric coating facility located on McCaffrey Street. According to their allegations, DuPont manufactured and sold aqueous fluoropolymer dispersions (AFD) containing ammonium perfluorooctanoate (APFO) to Saint-Gobain and Allied Signal, who used these products at the facility. APFO, when dissociated in water, forms perfluorooctanoate (PFO) and, under acidic conditions, transforms into PFOA, which contributed to the contamination. 

    Plaintiffs allege that DuPont supplied PFOA-containing AFD products to these companies from the 1950s through 2015, despite being aware of the health hazards associated with PFOA exposure by 1984. They further assert that DuPont was also aware of technologies that could have reduced or eliminated PFOA emissions but chose not to advise its customers or recommend testing for PFOA in groundwater near their facilities. Instead, DuPont allegedly prioritized profits over safety, continuing to sell these products without warning about the risks. 

    DuPont, in its defense, denied many of the allegations and disputed its role as a direct and proximate cause of the contamination. It argued that it was not a significant contributor to the contamination of the Hoosick Falls water supply. To support this, DuPont submitted expert reports from Adam Love and David Duffus, suggesting that the company contributed only around 15% of the total AFDs delivered to the McCaffrey Street facility between 1991 and 2003. Plaintiffs, however, sought to exclude their expert testimony, arguing that they were not relevant to the case. 

    Environment Engineering Expert Witness

    Dr. Adam Love earned a Bachelor of Arts in Geosciences from Franklin & Marshall College in 1996, followed by a Master of Science in Material Science and Mineral Engineering in 1998, and a Doctor of Philosophy in Civil and Environmental Engineering in 2002, both from the University of California, Berkeley. He accumulated over 20 years of experience in environmental forensics, site characterization, remediation, exposure assessment, human health risk, and contamination transport analysis. 

    From 1996 to 2002, Love worked as a graduate student researcher at UC Berkeley, contributing to contaminant transport and environmental forensic evaluations. He developed new techniques for environmental pollution reconstruction and allocation. From 2002 to 2009, he served as a scientist at the Forensic Science Center at Lawrence Livermore National Laboratory. 

    Discover more cases with Adam Love as an expert witness by ordering his comprehensive Expert Witness Profile report.   

    Forensic Accounting Expert Witness 

    David Duffus is a forensic accountant with over 25 years of experience across diverse industries. He earned a BA in Economics and Political Science, an MBA in Accounting and Finance, and held several professional designations, including CPA, ABV, CFE, and CFF. 

    Throughout his career, Duffus served as an expert on more than 100 occasions, testifying over 90 times in depositions, trials, and alternative dispute settings. He handled disputes involving values up to $275 million and project values exceeding $300 million. Additionally, he acted as an arbitrator and neutral accountant in post-acquisition and valuation-related disputes. 

    Since 1992, Duffus specialized in complex litigation services, forensic accounting, and valuation assignments for a wide range of businesses, from start-ups to Fortune 100 companies. He collaborated extensively with legal counsel through all phases of litigation, providing expert witness and deposition testimony in both state and federal courts, as well as in alternative dispute settings. Before joining HKA, Duffus dedicated nearly 17 years to Baker Tilly’s Global Forensics & Litigation Services practice, including 15 years as a partner. 

    Want to know more about the challenges David Duffus has faced? Get the full details with our Challenge Study report. 

    Discussion by the Court 

    Adam Love 

    Plaintiffs sought to exclude Love’s testimony on the grounds of irrelevance, asserting that his opinions did not cover the full period during which DuPont supplied chemicals to the McCaffrey Street site. They argued that Love’s data only reflected roughly a third of the known supply period, making it insufficient to determine DuPont’s contribution to the contamination. Plaintiffs further contended that his opinions did not make it less probable that DuPont significantly contributed to the contamination in Hoosick Falls. 

    The Court, however, found Love’s testimony relevant under Rule 401 of the Federal Rules of Evidence, which allows evidence that has any tendency to make a fact more or less probable. The comparative data he presented could reasonably lead a jury to conclude that DuPont was not a significant contributor to the contamination. Additionally, the Court noted that Love’s report explicitly recognized the limitations in the available data, particularly regarding the APFO content in the AFDs supplied by DuPont. While Plaintiffs argued that this limited scope could confuse the jury, the Court emphasized that such concerns could be addressed through cross-examination rather than by excluding the testimony. Thus, Love’s testimony was found to be both relevant and based on a sufficient foundation. 

    David Duffus 

    Plaintiffs also sought to exclude Duffus’ expert testimony, arguing that his reliance on a limited data set—specifically, records from Saint-Gobain covering a narrow time frame—rendered his conclusions irrelevant. Duffus’ report addressed DuPont’s supply of AFDs between 1991 and 2003, but Plaintiffs argued that this narrow focus could not accurately assess DuPont’s contribution to the contamination. 

    In response, the Court found Duffus’ testimony relevant under Rule 702, which establishes a broad standard for the admissibility of expert opinions. Despite the limited data set, the Court concluded that Duffus had based his opinions on the best available information, which was accessible to both parties. The Court also rejected Plaintiffs’ argument that the source of the data—Saint-Gobain—undermined the testimony’s foundation. Instead, it held that any limitations in Duffus’ analysis could be explored during cross-examination, rather than serving as grounds for exclusion. Permitting Plaintiffs’ able counsel to cross examine Duffus about the perceived limitations of the data set and what, if any, information can be gleaned from his opinion about DuPont’s potential contribution of APFOs is considered a better remedy than total preclusion of this opinion.

    Held 

    The Court denied the Plaintiffs’ motions to exclude expert testimonies from Adam Love and David Duffus, ruling they met relevance and admissibility standards under Federal Rules 401(a) and 702. 

    Key Takeaways: 

    • Relevance of Expert Testimony: The Court affirmed that expert testimony can be relevant even if it doesn’t cover the entire time period of alleged contamination. Partial data can still be useful in assessing a party’s potential contribution to environmental damage. 
    • Cross-Examination vs. Exclusion: The Court favored allowing expert testimony and subjecting it to cross-examination rather than excluding it entirely, even when there were potential limitations in the data or analysis. 
    • Foundation for Expert Opinions: The Court found that expert opinions based on limited available data can still have sufficient foundation, especially in cases where complete historical records may not exist. 
    • Source of Data: The Court determined that the source of data (in this case, from one of the parties) does not automatically render expert testimony inadmissible or lacking foundation.

    Please refer to the blog previously published about this case:

    Chemical Engineering Expert Witness’ Testimony About the Harms Surrounding PFOA Limited

    Case Details:

    Case Caption: Baker V. Saint-Gobain Performance Plastics Corp. 
    Docket Number: 1:16cv917 
    Court: United States District Court for the Northern District of New York 
    Order Date: September 13, 2024