Expert Witness Profiler

Tag: Chemical

  • Environmental Expert Was Allowed to Opine on the Impact of PCBs

    Environmental Expert Was Allowed to Opine on the Impact of PCBs

    The Burlington School District (“BSD” or “Plaintiff”) commenced this action after discovering polychlorinated biphenyls (“PCBs”) at Burlington High School (“BHS”). Defendants Monsanto Co., Solutia, Inc., and Pharmacia LLC (collectively “Monsanto” or “Defendants”) are allegedly successors to the old Monsanto company, which was the primary manufacturer of PCBs in the United States for several decades. BHS was constructed in the 1960s, and testing recently revealed the presence of PCBs in its buildings. The BSD concluded that because of PCB contamination, BHS had to be demolished.

    Defendants filed a motion to exclude all testimony of Plaintiff’s experts Wendy Pearson and Robert A. Wanat.

    Environmental Expert Witness

    Wendy N. Pearson is a licensed engineer who has worked at Matson & Associates for over 25 years.

    Pearson has bachelor’s and master’s degrees in civil engineering and environmental science and engineering. She has also conducted peer-reviewed research relating to environmental contamination, chemical manufacturing industry standards and practices, and chemical releases from manufacturing and industrial facilities.

    Discover more cases with Wendy Pearson as an expert witness by ordering her comprehensive Expert Witness Profile report.

    Chemistry Expert Witness

    Dr. Robert Adam Wanat holds an M.S. and a Ph.D. in chemistry from Cornell University. He has more than 30 years’ experience working for major chemical companies overseeing research and development of various chemical products. Since 2018, he has owned his own consulting company which specializes in the development, manufacture, and application of polymers, plastics, materials, and adhesives.

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

    Discussion by the Court

    I. Monsanto’s Knowledge

    Defendants first argued that opinions about what Monsanto should have known should be excluded. Their contention is that these witnesses’ testimonies about the environmental impacts of PCBs — based in part on information from Monsanto’s own archives — are “mere pronouncements” based on “subjective or speculative opinions” and would constitute a subjective interpretation “based on nothing more than a review of decades-old documents.”

    Pearson reviewed the state of the science related to PCBs over several decades, beginning in the 1930s. Pearson also explained the chemical nature of PCBs and what was known about their dangers. She did offer opinions about what Monsanto could have done to expand its knowledge. Those opinions are based on studies that were known in the scientific community and, in certain instances, by Monsanto itself.

    As a result, the Court found that Pearson’s testimony is not based on speculation. Nor did it constitute merely subjective narrations. Instead, they appeared to be supported by a substantial documentary record that provided a foundation for their opinions. 

    Wanat’s report is similarly supported. He will testify about chemical evaporation generally, and with respect to PCBs specifically. He will also reference Monsanto’s documents, including patents and technical bulletins.

    II. Standard of Care

    Defendants next argued that Pearson’s and Wanat’s opinions regarding industry standards cannot be admitted because they are not supported by sufficient facts, are not based on any methodology, and constitute improper legal conclusions.

    Pearson intended to testify that Monsanto defined its own standard of care and failed to live up to that standard. Wanat’s report is more limited, citing Monsanto’s adherence to American Conference of Government Hygienists thresholds.

    The Court questioned whether the materials in question establish a standard of care, or whether they instead constitute general statements of corporate responsibility. Regardless of the distinction, the Court found no reason to exclude the testimony of either Pearson or Wanat, insofar as their testimony is based on Monsanto’s own statements about its responsibilities.

    Defendants’ final argument is that testimony about the standard of care consisted of improper legal conclusions and stood in the shoes of the jury.

    Here, Plaintiff submitted that Wanat will use the term “reasonable” in its “ordinary, non-legal sense.” Defendants have not identified an element of a pending cause of action that would render the term “reasonable” an impermissible legal conclusion. Consequently, the Court declined to bar such testimony.

    Held

    The Court denied Defendants’ motion to exclude the expert testimony of Wendy Pearson and Robert Wanat.

    Key Takeaway

    To determine when a question posed to an expert witness calls for an improper legal conclusion, the district court should consider first whether the question tracks the language of the legal principle at issue or of the applicable statute, and second, whether any terms employed have specialized legal meaning.

    Case Details:

    Case Caption: Burlington School District V. Monsanto Co.
    Docket Number: 2:22cv215
    Court Name: United States District Court, Vermont
    Order Date: April 07, 2026
  • Environmental Engineering Expert’s Testimony on Workplace Exposure Admitted

    Environmental Engineering Expert’s Testimony on Workplace Exposure Admitted

    Anthony Perrotti was an engineer who designed navigation control systems for air- and spacecraft. Aside from a brief stint at another aerospace company, he worked for Lockheed for his entire career, from when he was an intern in college until he died from gastroesophageal cancer at age 47. After his death, Jennifer Perrotti, his widow, brought this suit against Lockheed for negligence and strict liability, alleging that toxic chemicals at the facility where he worked caused his cancer.

    Plaintiff relied on Dr. Ranajit Sahu, a fate-and-transport engineer to establish causation. The Court filed a motion to exclude the testimony of Sahu.

    Environmental Engineering Expert Witness

    Dr. Ranajit (Ron) Sahu has over thirty one years of experience in the fields of environmental, mechanical, and chemical engineering. He has over twenty eight years of project management experience and has successfully managed and executed numerous projects in this time period. He has provided consulting services to numerous private sector, public sector and public interest group clients.

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

    Discussion by the Court

    Sahu’s opinions are as follows. In the companion case, Sahu used Lockheed’s reported emission rates to model the concentrations of the substances at issue to which people in the area surrounding the facility were exposed, and then he compared those concentrations to the background exposures of the general population of the state. He concluded that the concentrations modeled in the area nearby were many times higher than the background exposures. The Court found that methodology reliable.

    Adopting that analysis in this case, Sahu then concluded that the decedent was “likely exposed” to the substances at issue via “occupational exposures.”

    Sahu characterized the decedent’s exposures as “elevated,” but he declined to quantify particular levels of exposure, instead performing a qualitative assessment. In his rebuttal report, Sahu noted that the studies he relied on concerning occupational exposures likewise did not quantify particular dosages.

    He pointed out that precise quantification would have required historical recordkeeping that Lockheed did not do, and he noted that any modeling he could conduct now would not capture the emissions to which this decedent in particular was exposed beginning three decades ago.

    Specifically, Lockheed argued: (1) because Sahu did not quantify the dose levels, no reliable data shows the decedent was likely exposed to the substances at issue; (2) Sahu’s failure to investigate exactly where the decedent worked in the facility and model exposures inside the facility means he cannot reliably show exposure; (3) the studies Sahu cited did not reliably support his conclusions because they do not all pertain to cancer; and (4) Sahu improperly relied on some data outside the time period of the decedent’s work.

    Analysis

    The Court held that the lack of a quantitative dosage assessment specific to the decedent did not make Sahu’s methodology unreliable. Based on his three decades of experience as an engineer in the field of air emissions, Sahu reconstructed data from the time of the decedent’s employment using Lockheed’s records to show the emissions coming from the facility, examined the ventilation system to determine that the decedent would have been exposed to those emissions through the air, and concluded that the decedent was likely exposed at elevated levels comparable to subjects in occupational exposure studies.

    Therefore, the conclusion that the decedent was exposed on-site at elevated levels logically flows from Sahu’s reliable opinion that individuals nearby were exposed to elevated levels against background.

    The Court found Lockheed’s secondary arguments similarly unavailing. Sahu explained that no matter where the decedent was working at the facility, he would have been exposed throughout.

    Sahu opined that insufficient containment and ventilation systems meant the decedent would have been exposed inside or out. He explained why he did not model inside the facility and why doing so would not have been useful anyway. He relied on studies examining occupational exposures because that was the opinion he was asked to provide—on workplace exposure, not the decedent’s particular cancer. Sahu referenced chemical usage records during the years of the decedent’s employment, and he explained that emissions prior to the decedent’s work also caused ongoing contamination.

    Held

    The Court denied Lockheed’s motion to exclude the testimony of Ranajit Sahu.

    Key Takeaway:

    Lockheed may quibble with exactly what Sahu’s opinion—that the decedent was “likely exposed” to the chemicals at “elevated” levels—can (and cannot) tell the jury about whether the chemicals caused his cancer. But there is nothing about this methodology or the data it interprets that is insufficient or unreliable from a Daubert standpoint.

    Case Details:

    Case Caption: Perrotti V. Lockheed Martin Corporation
    Docket Number: 6:22cv1338
    Court Name: United States District Court, Florida Middle
    Order Date: September 02, 2025
  • Chemical Engineering Expert Witness’ Testimony About the Harms Surrounding PFOA Limited

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

    This case involves a dispute concerning the contamination of the drinking water in Hoosick Falls, New York by perfluorooctanoic acid, a chemical commonly referred to as PFOA. Following multiple settlement agreements with certain Defendants, DuPont is the only remaining Defendant. Plaintiffs alleged that DuPont is liable for producing the PFOA that ultimately contaminated the water supply in Hoosick Falls. To bolster those allegations, Plaintiffs retained Dr. Michael Hickner to testify about the harms surrounding PFOA and DuPont’s knowledge thereof. 

    DuPont sought to preclude Hickner from offering the following opinions:

    (1) The Barr Processor Mass Balance Study released in 2005 definitively demonstrated that PFOA was not destroyed during AFD processing and that IR heated ovens released into the air . . . PFOA vapor during processing;

    (2) DuPont was aware since the 1980s that when AFD was heated to temperatures above 150 [degrees Celsius] APFO in the AFD would sublime to form PFOA vapors;

    (3) DuPont was aware at least since the mid-1990s that PFOA was stable at 250 [degrees Celsius] and had a half-life of 31.5 minutes when heated to 300 [degrees Celsius];

    (4) DuPont was aware since the 1970s that [released] PFOA . . . would not reach 300 [degrees Celsius] for more than a few minutes; and

    (5) DuPont recognized in the 1980s that PFOA released from heating AFD could contaminate drinking water and began a program to capture and recycle PFOA released from its fine powder dryers using scrubbers and other technologies.

    Chemical Engineering Expert Witness

    Michael Hickner has a Ph.D. in chemical engineering and is a researcher and professor in materials engineering and materials sciences. At the time he completed his report, he was a professor of Materials Science and Engineering at Penn State University. In 2023, he became an endowed professor in the Department of Chemical Engineering at Michigan State University. Since 1998, he has conducted research regarding polymers and has worked with fluoropolymers such as those contained in AFD, which are the focus of this case Hickner has taught classes in chemistry, polymers, and materials science.

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

    Discussion by the Court

    Opinion # 1

    DuPont first sought to exclude Hickner’s opinion that the Barr Study definitively demonstrated that PFOA was not destroyed during AFD processing but instead was released into the air. DuPont does so on the basis that Hickner “offer[ed] nothing more than an interpretive narration of documents” to arrive at his conclusion.”

    In formulating his opinion, Hickner summarized the findings of the Barr Processor Mass Balance Study “performed in response to EPA’s concerns about PFOA in the environment.” He stated that the “study demonstrated that 39-54% of [chemicals were] released through the air to the environment as PFOA through the [infrared] oven process.” He goes on to state a number of statistics detailed in the Barr Study. Hickner uses these statistics and other chemical data to support his ultimate finding that the Barr Study demonstrates that PFOA was released into the air rather than destroyed during processing.

    DuPont takes issue with this method, arguing that the ultimate opinion is a “factual narrative based on nothing more than a review of documents and testimony.” The Court believed that the Barr Study summarized by Hickner is sixty-seven pages of highly technical and scientific data regarding AFD processing, infrared ovens, PFOA vapor release, and other scientific data. In other words, Hickner’s testimony would “streamline the presentation of that data to the jury, saving the jury time and avoiding unnecessary confusion.”

    Opinions ## 2-5

    Opinions two through five all concern what DuPont was “aware” of and “recognized” and when. Black’s Law Dictionary defines to “become aware of” as to have “specific knowledge of something.” The Court held that Hickner’s opinions all concern what DuPont knew and when. To allow such testimony would be to wrongly supplant the role of the jury. This is especially true because Hickner has no expertise in the field of corporate governance from which he could offer opinions about how knowledge held by some individuals in a corporation could be imputed to the corporation itself.

    The Court added that Hickner may offer testimony on the scientific data supporting his ultimate conclusions provided he does not opine on DuPont’s knowledge. 

    Held

    The Court granted in part and denied in part the Defendant’s motion to exclude expert testimony from Dr. Michael Hickner. Hickner’s testimony was limited to his opinion on the Barr Study, the general science behind chemical processing and PFOA, and what information was available about that science to individuals associated with DuPont.

    Key Takeaway:

    If expert testimony is permitted to aid a jury in understanding business practices, the Court is comfortable finding that expert testimony would aid the jury here where the scientific data at issue is dense, complex, and difficult to understand without specialized knowledge. 

    Case Details:

    Case Caption: Baker Et Al V. Saint-Gobain Performance Plastics Corp. Et Al
    Docket Number: 1:16cv917
    Court: United States District Court, New York Northern
    Order Date: September 12, 2024