In re Bard Implanted Port Catheter Products Liability Litigation
U.S. District Court, District of Arizona · D. Ariz. · Arizona bar guidance
Conduct
Defendants argued in reply that plaintiffs' expert misled them about using ChatGPT, citing hallucinated citations in a different case-specific report he wrote in the MDL.
Consequence
Here the court refused to consider the late AI argument, held that mere suspicion could not exclude the expert, and limited his opinions only on unrelated grounds.
Lesson
Here an expert's admitted ChatGPT use did not support exclusion without a hallucinated source identified in the report actually at issue.
Verified September 29, 2026
- Citation
- In re Bard Implanted Port Catheter Products Liability Litigation, MDL No. 3081, Order (D. Ariz. Aug. 12, 2026), ECF No. 10030
- Decided
- August 12, 2026
Summary
In this multidistrict litigation over Bard implanted port catheters, the defendants moved to exclude the opinions of plaintiffs' materials science expert, Dr. Ahmed El-Ghannam. For the first time in their reply brief, they argued that El-Ghannam "gave deliberately misleading testimony" about his AI use "that destroys his credibility and reliability and renders his entire opinion inadmissible." They did not identify any AI-generated portion of his general report. Instead, they argued that "numerous citations are now suspicious" because hallucinated citations had appeared in an El-Ghannam case-specific report in the MDL (in a case since dismissed), while acknowledging that "Bard has not identified any fully hallucinated citations in the General Report." At deposition, El-Ghannam testified: "I use all engines, including ChatGPT, and I go to the references and read these articles and put my report based on that." Asked whether he cut and pasted from ChatGPT, he said he did not remember but that his "general way of writing my report is that I read and check the references and write my report on that basis." Asked whether he used an AI program to write or edit his report, he answered, "I wrote the report by myself."
- AI tool:
- ChatGPT (plaintiffs' expert Dr. Ahmed El-Ghannam acknowledged at deposition that he used "all engines, including ChatGPT"; defendants identified no hallucinated citation in the report at issue)
- Amount or terms:
- None; the AI-based challenge to the expert was rejected
How did the court address the AI-related conduct?
The court declined to consider the AI argument because courts do not consider arguments raised for the first time in a reply brief. The court added that "[m]ere suspicion is not enough to exclude El-Ghannam's opinions," distinguished Kohls v. Ellison as a case involving confirmed AI-hallucinated sources in an expert declaration, noted that the defendants' other cases involved plagiarism, which they implied but did not directly argue or support with evidence, and observed that the defendants' own authority acknowledges experts may use AI in the report-writing process. It relied on El-Ghannam's testimony that he wrote the report and on his signed report confirming the opinions are his own. On other grounds, the court granted the motion in part: El-Ghannam may not opine that the cracking of the catheter's surface was likely caused by Bard's manufacturing processes, or on the cause of one patient's infection and biofilm. The motion was otherwise denied.
Why does In re Bard Implanted Port Catheter Products Liability Litigation matter for law firms using AI?
This order addresses AI in an expert report from the side of a challenge that failed. The defendants did not show any hallucinated source in the general report; they relied on hallucinated citations in a different, case-specific report by the same expert and on his deposition answers about ChatGPT. The court declined to consider the argument because it was raised first in reply, and also observed that “[m]ere suspicion is not enough.”
The court also noted that experts may use AI in writing reports. It quoted the defendants’ own authority, Kohls v. Ellison, for the point that the court there “does not fault Professor Hancock for using AI for research purposes,” and distinguished Kohls because that case involved “confirmed AI-hallucinated sources.” Here the expert testified that he reads and checks the references and “wrote the report by myself,” and the signed report confirmed the opinions were his.
The partial exclusion that followed rested on the court’s Rule 702 analysis of two specific opinions, not on AI. Firms documenting compliance may wish to consider that, in this MDL, an expert’s AI use became a litigation issue because of errors in a different report, and that the court observed the defendants had identified nothing hallucinated in the general report before it.
Implications for your firm
Operational steps a firm reading this case may wish to consider documenting. Strategic and rule-application calls belong to your firm's attorneys.
- Document any challenge to an expert's AI use in the opening motion, with the specific AI-generated passages identified; here the argument was raised only in reply and was not considered.
- Review retained experts' reports for AI-generated citations across every report they file in a litigation; here hallucinated citations in one case-specific report prompted a challenge to the general report.
- Verify that experts can testify to how they used AI tools and that they checked the cited references, as this expert did in the testimony the court relied on.
Sources
Primary sources
- The case-specific El-Ghannam report said to contain hallucinated citations, and the dismissed case in which it was filed (Doc. 8389), are not identified by name in this order and were not reviewed.