Expert witness for ChatGPT says 3M bears no liability
| Source: HN | Original article
ChatGPT generated most of a 3M expert report, drafting 85% after a prompt to prove zero liability, with 350 pages of chat logs revealed in discovery.
An expert witness hired by 3M relied on ChatGPT to draft the bulk of a defense report in a $61 million lawsuit stemming from a fatal explosion at the company’s Watson Grinding plant. Court filings reveal that the attorney‑expert, who charges $475 an hour, fed the chatbot prompts such as “create an exceptional expert witness report defending the standard of care at 3M” and “show how 3M is 0 % at fault for the explosion.” Trial testimony estimates that 85‑90 % of the 350‑page document was generated by the AI, and more than 350 pages of prompt‑and‑response logs have now entered the discovery record.
The episode spotlights the growing, and still opaque, role of generative AI in high‑stakes litigation. If a machine can produce the substantive arguments that shape a jury’s view of liability, questions arise about the expert’s duty to verify accuracy, the admissibility of AI‑generated analysis, and the potential for undisclosed bias. The discovery of the chat logs also raises transparency concerns: courts may need to decide whether parties must disclose the extent of AI assistance and how to evaluate its reliability.
Legal observers will be watching how the judge rules on the admissibility of the report and whether any sanctions follow the revelation of extensive AI use. The case could prompt tighter discovery rules around AI prompts, spur discussions on professional responsibility for lawyers and experts, and accelerate calls for watermarking or other provenance tools—issues we flagged in earlier coverage of AI adoption in professional settings [2026‑08‑18] We still don’t know how people are really using AI (id 11911). The outcome may set a precedent for how courts treat AI‑crafted testimony in future lawsuits.
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