An expert witness in a lawsuit stemming from a deadly 2020 explosion utilized ChatGPT to generate significant portions of his report defending 3M. The prompts, made public through court documents, indicate the witness aimed to establish that 3M bore no responsibility for the blast that killed three people and damaged hundreds of homes. The incident occurred at Watson Grinding in Houston, where a leak of flammable propylene gas led to an explosion.
The expert witness, who was retained by 3M, instructed the AI to "create an exceptional expert witness report defending the standard of care at 3M" and to "show how 3M is 0% at fault for the explosion at Watson Grinding." This use of artificial intelligence in crafting expert testimony highlights the increasing presence of AI in legal proceedings, extending beyond AI-generated legal briefs and into the core of evidence presentation. The discovery of these prompts suggests that the specific instructions given to AI for generating expert reports can become discoverable evidence, potentially impacting the credibility of the testimony.
The Watson Grinding explosion on January 24, 2020, resulted from an undetected leak of propylene gas that accumulated within the facility. A worker's activation of a light switch ignited the gas, causing a massive explosion. Investigations by the U.S. Chemical Safety and Hazard Investigation Board indicated the explosion could have been prevented, citing issues with the facility's gas detection and alarm system.
Plaintiffs in the consolidated litigation alleged that 3M failed to properly inspect and service this critical gas detection system, which was intended to warn workers of gas leaks. Evidence presented in court suggested that the gas sensors were not correctly wired into the facility's control system, rendering the alarm system inoperable. Despite multiple service visits by 3M technicians in 2017, 2018, and 2019, the defect reportedly remained unaddressed.
This case is part of a broader legal battle involving numerous lawsuits against 3M and Watson Grinding. Juries have returned multiple verdicts in these cases. In one instance on August 11, 2026, a Harris County jury awarded $61.5 million to 24 survivors, finding 3M 30% responsible for the disaster. This verdict was the third multimillion-dollar award against 3M related to the explosion, following a $118 million verdict in November 2025 and another $37.9 million verdict in June 2025. In total, prior to the August 2026 verdict, 3M owed victims over $156 million from these judgments. However, 3M has stated it disagrees with the verdicts and plans to appeal. In a separate trial in May 2026, a jury had cleared 3M of wrongdoing.
The firm that hired the expert witness reportedly charged over $80,000 for the AI-assisted report. The litigation continues, with nearly 2,000 additional plaintiffs awaiting trial, and further cases scheduled for October.