Toxicology Expert’s Report Exceeds the Bounds of Permissible Supplementation
Posted on June 3, 2025 by Expert Witness Profiler
Michelle Young, the surviving spouse of Ernest James Young and Amanda Fries, the daughter and heir of Young filed the underlying lawsuit alleging that Young’s death from pancreatic cancer was caused by his exposure to radioactive contaminants that were released by the Defendants’ negligent operation of a uranium processing plant in Gore, Oklahoma, near where Young grew up.
On December 6, 2024, Plaintiffs disclosed and provided the expert report of James Clark, Ph.D. On March 6, 2025, Plaintiffs submitted a report entitled ‘Supplemental Opinions’ of Clark, Ph.D. (“March Report”).
Defendants filed a motion to strike the March Report pursuant to Fed. R. Civ. P. 37(c)(1), arguing it is an improper attempt to supplement the December Report because it is an unauthorized sur-rebuttal expert report.
Toxicology Expert Witness
James Clark is a well-recognized toxicologist, air modeler, and health scientist specializing in dose reconstruction. He has 30 years of experience in tying together environmental contaminants measurements to human health impacts.
Discussion by the Court
Propriety of Clark’s March Supplemental Report
Defendants argued that Clark’s March Report is an improper supplement because it did not correct any inaccuracies or complete an incomplete disclosure in his December Report. Instead, Defendants argued, Clark’s March report added a completely new analysis regarding Young’s radionuclide absorption and exposure and offered four or five new sweeping opinions.
Plaintiffs first argued that Rule 26(a)(2)(D)(ii) expressly allowed rebuttal reports and that the March Report was Clark’s rebuttal response to criticisms set out in the opposing expert’s report. Plaintiffs next argued that Clark’s March Report was an appropriate supplement to his December Report because he simply filled in an incomplete aspect of his December Report – calculated the previously uncalculated radionuclide absorption in Young’s cremains. Finally, Plaintiffs argued that Clark’s March Report was timely because Rule 26(a)(3) provides for such supplement no later than the required pretrial disclosures.
Analysis
The Court noted that Plaintiffs sought neither to amend the schedule nor leave to file the March Report.
Moreover, Clark’s March Report was not a proper supplement to his December Report. In the December Report, Clark opined that Young’s cremains contained from 2 to 4.5 times as much radiation when compared to the average value in cremains of other Colorado residents. In his March Report, Clark took the additional step of calculating the additional radiation exposure by year experienced by Young based on the analysis of radiation in Young’s cremains as compared to other Colorado residents.
Since Clark merely attempted to “strengthen” or “deepen” his opinion expressed in the December Report by making calculations that he could have made in the December Report, the Court held that Clark’s March Report exceeded the bounds of permissible supplementation and is subject to exclusion under Fed. R. Civ. P. 37(c)(1).
Whether a Rule 26(a) Violation is Justified or Harmless
Defendants argued that they are prejudiced because of the late disclosure of Clark’s opinions in the March Report and because they will have to seek leave to file a sur-sur rebuttal report. Plaintiffs argued that Defendants will not suffer any prejudice or, to the extent they do, it is easily curable because the discovery deadline was extended by ninety days. While Plaintiffs are correct that the discovery and related deadlines were extended, the expert disclosure and rebuttal deadlines were not. It is apparent that permitting Clark’s March Report will likely disrupt the trial of this case.
Moreover, Clark acted willfully in that he knew or should have known that his opinions regarding Young’s radiation exposure would be stronger if accompanied by a radionuclide absorption analysis. After all, Clark could have performed the radionuclide absorption analysis as part of his December Report.
Held
The Court granted the Defendants’ motion to strike the Plaintiffs’ purported supplemental expert report of James Clark.
Key Takeaway:
A supplemental expert report that states additional opinions or rationales or seeks to “strengthen” or “deepen” opinions expressed in the original expert report exceeds the bounds of permissible supplementation and is subject to exclusion under Rule 37(c)(1).
Case Details:
| Case Caption: | Young Et Al V. Sequoyah Fuels Corp. Et Al |
| Docket Number: | 6:22cv280 |
| Court Name: | United States District Court, Oklahoma Eastern |
| Order Date: | June 02, 2025 |
