Tag: Threshold

  • 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
  • Pediatrics Expert’s Opinion Regarding a Target 95% Vaccination Rate Met the Daubert Bar

    Pediatrics Expert’s Opinion Regarding a Target 95% Vaccination Rate Met the Daubert Bar

    On July 22, 2022, Dr. Gregory Fox, individually and as parent of C.F., and Rita Fox, individually and as parent of C.F. (jointly, the Plaintiffs), filed a lawsuit challenging the state of Maine’s public school vaccination requirements.

    Dr. Laura Blaisdell, a pediatrician with extensive qualifications in medicine and public health, was presented as an expert witness by Department of Education Commissioner Pender Makin. Fox’s challenge centered on Blaisdell’s opinion regarding a 95% vaccination rate target. He argued that her reliance on the R0 variable, which assumes a “totally susceptible” population, was unreliable and unsupported by scientific methodology when applied to the case’s specific facts. He claimed her assumption was erroneous because the population in question was only “partially susceptible”.

    Furthermore, Fox contested the scientific support for the 95% vaccination coverage goal, asserting that Blaisdell erred in inferring its necessity to protect susceptible individuals or halt disease transmission.

    Pediatrics Expert Witness

    Laura L. Blaisdell, MD, MPH, FAAP, CPE is a board-certified pediatrician, public health consultant, and researcher with expertise in vaccine hesitancy, infectious disease control, and camp medicine. She holds a Doctor of Medicine (MD) from the University of Minnesota Medical School and a Master of Public Health (MPH) from the University of Minnesota School of Public Health. She is also a Certified Physician Executive (CPE) and a Fellow of the American Academy of Pediatrics (FAAP).

    Blaisdell has served as an Attending Physician in the Department of Pediatrics at Maine Medical Center since 2008 and is an Assistant Professor at Tufts University School of Medicine. Her research and clinical work focus on vaccine decision-making, public health policy, and disease prevention in communal settings, particularly youth camps. She has been a key figure in vaccine advocacy and has contributed to legislative efforts to promote immunization policies.

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

    Discussion by the Court

    Commissioner Makin countered that Fox conflated herd immunity threshold rates with public health vaccination targets for schools. They argued that Blaisdell’s use of R0 was a generally accepted practice for determining herd immunity thresholds.

    Regarding the 95% target, the Commissioner emphasized that it was a public health goal, not a herd immunity threshold, aligning with targets set by the United States Centers for Disease Control and Prevention (U.S. CDC) and the Maine Center for Disease Control and Prevention (Maine CDC). Blaisdell, in her deposition, clarified the distinction, stating that the 95% figure represents a public health recommendation for school vaccination levels.

    Analysis

    The Court acknowledged that Blaisdell’s use of R0 to calculate herd immunity thresholds was supported by scientific literature, including articles cited by both parties. While the use of this methodology in other scientific literature is not conclusive, it did demonstrate a measure of acceptance within the scientific community.

    The Court ruled that Fox’s challenge regarding the “partially susceptible” population goes to the weight and credibility of Blaisdell’s testimony, not its admissibility. The Court also recognized the distinction between herd immunity thresholds and public health vaccination goals.

    Blaisdell’s reliance on sources like the CDC and state health reports, as well as her clear explanation during deposition, provided sufficient support for the 95% target as a public health goal. Moreover, Blaisdell sufficiently distinguished herd immunity threshold calculations from the public health goal of 95% vaccination coverage. Therefore, challenges to the weight and credibility of the 95% goal did not prevent the testimony from being admissible.

    Held

    The Court dismissed without prejudice Gregory Fox’s motion to partially exclude the testimony of Dr. Laura Blaisdell.

    Key Takeaway:

    This case highlights the importance of distinguishing between different types of scientific targets, such as herd immunity thresholds and public health goals. It also demonstrates the Court’s role in evaluating the reliability and relevance of expert testimony under the Daubert standard. The Court’s decision emphasizes that challenges to the factual underpinnings of expert opinions primarily affect their weight and credibility, not necessarily their admissibility.

    Case Details:

    Case Caption: Fox Et Al V. Makin Et Al
    Docket Number: 2:22cv251
    Court: United States District Court, Maine
    Order Date: March 10, 2025