UW-Madison Lab Worker Charged for Poisoning Colleague's Water, Shoes

Prosecutors say Makoto Kuroda used lab chemicals to contaminate coworker's belongings out of anger over promotion and workplace rules.

Apr. 16, 2026 at 12:23am

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An extreme close-up of a shattered glass beaker reflecting a bright, harsh flash of light, conceptually illustrating the dangerous chemicals used in a workplace poisoning incident.A lab worker's alleged chemical tampering with a colleague's belongings exposes the risks of workplace rivalries in sensitive research environments.Madison Today

A 41-year-old researcher at the University of Wisconsin-Madison's Influenza Research Institute has been charged with second-degree recklessly endangering safety and tampering with household products after allegedly using lab chemicals to contaminate a coworker's water bottle and shoes. Makoto Kuroda admitted to taking paraformaldehyde and Trizol from the lab fridge and putting small amounts in the coworker's water and shoes, saying he wanted the person to vomit and suffer skin irritation.

Why it matters

This case highlights the risks of workplace rivalries escalating to criminal behavior, especially in sensitive research environments where access to dangerous chemicals is possible. It raises questions about lab safety protocols, employee mental health support, and the need for stronger oversight to prevent such incidents.

The details

According to the criminal complaint, Kuroda texted another colleague saying 'I did it. I have also informed the person himself.' The coworker noticed his water had a 'chemical taste' and smelled of chloroform, which is used in the Trizol mixture researchers at the institute use. The State Lab of Hygiene confirmed the water tested positive for chloroform. Kuroda told police he was angry over the coworker's promotion and annoyed by what he described as 'pet peeves', including the colleague's failure to wear a lab coat and goggles.

  • The alleged incident occurred on April 5, 2026.
  • Kuroda was released on a $5,000 cash bond and is due back in court next Tuesday.

The players

Makoto Kuroda

A 41-year-old researcher at the University of Wisconsin-Madison's Influenza Research Institute who has been charged with second-degree recklessly endangering safety and tampering with household products.

Coworker

The victim of Kuroda's alleged chemical contamination of a water bottle and shoes.

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What they’re saying

“I did it. I have also informed the person himself.”

— Makoto Kuroda, Researcher

What’s next

The judge will decide next Tuesday whether to allow Kuroda to remain out on bail as the case proceeds.

The takeaway

This incident underscores the need for robust lab safety protocols, employee mental health support, and stronger oversight in sensitive research environments to prevent workplace rivalries from escalating into criminal behavior that jeopardizes public safety.