Opening statements in the fourth bellwether trial against 3M Company — stemming from a fatal explosion that rocked a West Houston neighborhood in 2020 — had an air of déjà vu Tuesday as the plaintiffs’ lawyers urged jurors to find 3M at fault, while attorneys for the multinational conglomerate argued the actions, and inactions, of Watson Grinding and Manufacturing leadership was solely to blame.
Testimony in the latest trial, involving 30 plaintiffs, started Tuesday morning and is expected to last through the first week of August. Most recently, in May, jurors in Harris County unanimously cleared 3M of any liability for the early-morning propylene gas leak and explosion that killed two employees of Watson and one nearby resident.
In June 2025, jurors awarded $37.9 million in damages to five plaintiffs. In November 2025, seven victims were awarded more than $118 million by a different jury. The lawsuits filed on behalf of more than 2,600 plaintiffs in the wake of the explosion were consolidated into multidistrict litigation for pretrial proceedings.
The plaintiffs in each case allege 3M’s failure to properly service a gas detection system at the Watson Grinding facility caused the disaster.
Experts concluded the cause of the 2020 explosion that killed two employees and one nearby resident was an undetected propylene gas leak. About 600 gallons of the gas filled the Watson Grinding facility overnight and into the early morning hours of Jan. 24, 2020. The gas ignited at 4:24 a.m., when an employee entered the building and flipped on a light switch.
The massive explosion could be felt and heard for miles.
The company specialized in applying thermal spray coatings to metal parts used in corrosive environments, such as fracking, offshore oil and gas operations, refining, power generation and aerospace. Propylene gas was used in the application process.
Watson Grinding filed for Chapter 11 bankruptcy Feb. 6, 2020, and was later liquidated.
Rob Kwok of Kwok Daniel, who represents a dozen of the 30 plaintiffs in this trial, held in one hand a small alarm topped with a red light. He said had Watson spent $200 to purchase that alarm, or one like it, to be installed in the coating booths, the explosion would never have happened. In this case, the injuries of the plaintiffs range from hearing loss to spine and neck surgeries, and some are suing to recover damages related to the destruction or damage done to their homes by the blast.
He did not shy away from Watson’s fault for the incident, telling jurors that both the premises owners and the “gas detection experts,” 3M, were responsible for what happened. He said while Watson’s “negligence” is a proximate cause of the blast, there can be “more than one cause of this explosion.”
“They’re about to get up here for an hour and tell you everything Watson did wrong,” Kwok said, gesturing toward the defense table. “I’ll save them the time. … Watson made all kinds of mistakes.”
Repeating a refrain from the third trial, Kwok told the jury that safety systems like the gas detection system Watson had installed in its facility exist because “people make mistakes.” He showed jurors three years of invoices from annual servicing of the system where he said notes from the technicians investigating the system were “at best” “unclear” regarding whether further action was required or if the system was properly functioning.
Kwok also teased for jurors they would be hearing from the 3M expert at trial. He played a snippet of the expert’s deposition testimony where lawyers questioned his use of AI to compile an expert report and drilled down on his prompt that asked the technology to help him find 3M zero percent at fault.
3M’s lead trial lawyer, Zandra Foley of Thompson, Coe, Cousins & Irons, told jurors that in 2008 there was a fire at the Watson Grinding facility that destroyed the building where thermal spray coatings were applied. In the wake of that, she said, the company developed policies and procedures intended to make operations safer and avoid future disasters.
But the company’s leadership failed to ensure the safety measures — such as turning off the gas valves inside the building as well as a main valve outside the building leading to the 2,000-pound propylene tank every night — were followed.
“An explosion like this, it’s never just one thing … and in this case there were multiple failures,” she said, noting that the company also failed to follow its own guidebook created after the 2008 explosion that said explosion-proof electrical systems should be installed.
“Had they just done one thing different, we wouldn’t be here today,” she said. “… These leaders systematically took shortcuts.”
Going through gas detection system service invoices, Foley pointed out to jurors that on page after page technicians noted that the system was not properly communicating with the company’s industrial computer, called a programmable logic controller, or PLC, that was a necessary part of the warning system.
“They didn’t do anything about it,” she said.
The panel of 12 jurors and two alternates is composed of eight women and four men.
Harris County District Judge Kristen Brauchle Hawkins is presiding over the trial.
The plaintiffs are represented by Robert Kwok, J. Ryan Loya, William Hoke, Ranny Sawaf and Marcos Cardenas of Kwok Daniel, William Moye of Moye Law Firm, Ryan Pigg of The Buzbee Law Firm, Adam Lewis of Arnold & Itkin, Eric Dick of Dick Law Firm, Adam Anthony of The Anthony Law Firm and Douglas Alexander, Marcy Hogan Greer, Anna Baker and Hannah Roblyer of Alexander Dubose & Jefferson.
3M is represented by Zandra Foley, John Flud, Kevin Risley and Zachary Nye of Thompson, Coe, Cousins & Irons, Sybil L. Dunlop of Greene Espel and Paul R. Garcia of 3M.
The case number is 2020-05505A. The case number for the MDL is 2021-15294.