---
title: "Testimony of Industrial Hygiene Expert Witness Admitted Despite her Alleged Lack of Firsthand Knowledge"
meta:
  "og:description": "Industrial Hygiene Expert Witness adopted methods which are common to the field of industrial hygiene"
  "og:title": "Testimony of Industrial Hygiene Expert Witness Admitted Despite her Alleged Lack of Firsthand Knowledge"
  author: "Expert Witness Profiler"
  description: "Industrial Hygiene Expert Witness adopted methods which are common to the field of industrial hygiene"
---

# Testimony of Industrial Hygiene Expert Witness Admitted Despite her Alleged Lack of Firsthand Knowledge

Posted on June 25, 2024 by Expert Witness Profiler

A district judge in California admitted the testimony of an industrial hygienist despite the legitimacy of her method being attacked.

Plaintiffs, former employees of Defendant, Bay Area Rapid Transit District (“BART”) brought First Amendment, Title VII, and FEHA claims against BART after losing their jobs due to their refusal to comply with BART’s COVID-19 vaccine mandate. 

BART disclosed, _inter alia_, the expert report of [Nancy McClellan](https://expertwitnessprofiler.com/expert-witness/Nancy-McClellan/1542538), an industrial hygienist. The McClellan report concluded, based on the above, that “BART worksites were moderate to high in their COVID-19 transmission risk, warranting a vaccine mandate [and the expectation of] 100% compliance,” and that “BART’s interpretation of the feasibility of the less effective administrative and PPE controls as secondary to vaccination was correct according to the classic hierarchy of controls.”

Plaintiffs filed a _Daubert_ motion seeking to exclude, or in the alternative limit, the testimony of McClellan.

## **Industrial Hygiene Expert Witness**

[Nancy McClellan](https://expertwitnessprofiler.com/expert-witness/Nancy-McClellan/1542538) holds a B.S. in Medical Technology from Michigan State University and a Master of Public Health with a focus on Industrial Hygiene from the University of Michigan. She has worked as an industrial hygienist for some 25 years and is certified by the American Board of Industrial Hygiene. She has served as the Chair of the American Industrial Hygiene Association, among other professional organizations, and currently serves on its Executive Board of Directors. McClellan has worked as an industrial hygiene consultant or testifying expert in several industries, including car manufacturing, pharmaceuticals, ordinance storage and testing, agriculture, and others. Expert McClellan has also worked on COVID-19. She provided guidance on controls for COVID-19 transmission in airports and other facilities, as well as the efficacy of air filtration systems on airplanes. 

[Discover more cases with Nancy McClellan as an expert witness by ordering her comprehensive Expert Witness Profile report.](https://app.expertwitnessprofiler.com/login?eId=1542538)

## **Discussion by the Court**

The Court held that the McClellan report was relevant to issues central to BART’s burden under both Title VII and FEHA. To meet its burden under Title VII, BART must show that accommodating unvaccinated employees would have imposed an undue hardship on BART.

The McClellan report ultimately concluded that engineering controls, such as vaccination, constituted the best feasible controls during the pandemic and that, in light of her worksite risk assessment, “BART’s interpretation of the feasibility of the less effective administrative and PPE controls as secondary to vaccination was correct.”

The Court also held the contents of both the McClellan report and the sources cited therein suggest that the methods underpinning McClellan’s analysis — namely the hierarchy of controls and worksite risk assessment — are common to the field of industrial hygiene. In other words, McClellan’s testimony was based on sufficient facts and data.

#### **McClellan is not an Expert in a Cognizable Field**

When Plaintiffs argued that McClellan is not an expert in a cognizable field: she is, instead, an “all-purpose expert” “market[ed] . . . in many divergent areas loosely categorized as industrial health,” the Court held that Plaintiffs’ characterization of McClellan’s experience omitted key details. McClellan had significant prior experience with COVID-19 and in any event, Plaintiffs’ assertion that industrial hygienists are so finely specialized as to require a “transit industrial hygienist” as opposed to an “ordinance testing industrial hygienist” was unsupported.

#### **The** **Legitimacy of McClellan’s Method was Questioned**

Plaintiffs attacked the legitimacy of McClellan’s method: ” McClellan claims that . . . the hierarchy of controls, is the same regardless of whether pickles are being made, bombs are being blown up, automotive parts [are] being made or pharmaceuticals [are] being manufactured. . . . This proves too much.”

The Court held that the hierarchy of controls is “an ingrained part of OSHA’s regulatory framework” for air contaminants in the workplace, and has been codified in Title 29’s Occupational Safety and Health Standards. Henceforth, McClellan’s assertion that the hierarchy of controls is “the fundamental principle for how [industrial hygienists] go about any biological chemical or physical exposure [and] how to address it” is supported.

#### **McClellan Lacked Firsthand Knowledge**

Plaintiffs advanced a number of arguments attacking McClellan’s “lack of firsthand knowledge.” The Court held that an expert is permitted wide latitude to offer opinions, including those that are not based on firsthand knowledge or observation. Moreover, Plaintiffs’ suggestion that McClellan should have contacted each Individual Plaintiff prior to preparing her report cuts against the norms of expert practice.

## **Held**

The Court denied Plaintiffs’ motion to exclude Defendant’s expert Nancy McClellan.

## **Key Takeaway:**

When Plaintiffs contended that McClellan lacked expertise in COVID-19, vaccines, or transit agencies, the Court held that there is no requirement that an expert be a specialist in a given field.

Also, the Court deemed McClellan’s assertion that the hierarchy of controls is “the fundamental principle for how [industrial hygienists] go about any biological chemical or physical exposure [and] how to address it” fully supported. According to the Court, Plaintiffs have identified various grounds for “vigorous cross-examination,” not exclusion.

## **Case Details:**

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