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Robert W Malone, MD@RWMaloneMD · Jun 4, 2026

A scientist was hired by a chemical company to study its weedkiller. He found it was castrating and feminizing frogs.…

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Summary

Scientist Tyrone Hayes discovered that the herbicide atrazine chemically castrates and feminizes frogs, but the chemical company responded by investigating and discrediting him rather than addressing the findings. Despite being classified as probably carcinogenic by the WHO in 2025 and banned in Europe since 2004, the EPA still permits atrazine in US drinking water at levels 30 times higher than EU standards, and it persists in groundwater and accumulates in conventional milk.

Summarized by ThreadOut AI from the full thread. May miss nuance — read the thread below.

  1. #1

    A scientist was hired by a chemical company to study its weedkiller. He found it was castrating and feminizing frogs. So the company stopped studying the chemical and started studying him. This is the documented story of atrazine. 🧵

  2. #2

    Tyrone Hayes, a Berkeley biologist, found atrazine scrambled frog sexual development. Genetically male frogs were chemically castrated. Some were so feminized they mated with other males and laid viable eggs. Published in PNAS.

  3. #3

    Internal records later unsealed in litigation showed the company's PR team drew up goals. Goal number one: "discredit Hayes." Notes described investigating his wife, tracking his talks, and keeping a roster of ~130 supposedly independent experts to deploy on demand.

  4. #4

    This is not a theory. It is court exhibits, reported by the New Yorker, Mother Jones, and a nonprofit investigative newsroom. A company that makes a chemical built a psychological profile of the scientist who questioned it. Sit with that.

  5. #5

    November 2025: the WHO's cancer agency reclassified atrazine as "probably carcinogenic to humans." Same agency, same tier it gave glyphosate. The EPA still calls it safe as used.

  6. #6

    Here is the part most people miss. You do not mainly eat atrazine. You drink it. It washes off fields into streams and leaches into aquifers, where it persists for years. Germany banned it in 1991 and it was still the most abundant pesticide in their groundwater 18 years later.

  7. #7

    The US caps atrazine in drinking water at 3 micrograms per liter. The EU caps any pesticide at 0.1, thirty times stricter, and banned atrazine outright in 2004. Same molecule, same biology, two regulators an order of magnitude apart. One is wrong about your family's water.

  8. #8

    It bioaccumulates up into milk through feed and water. In US retail testing, conventional milk carried atrazine in about a quarter of samples. Organic milk tested clean, every sample. For a staple kids drink by the gallon, buying organic closes a door you actually control.

  9. #9

    MAHA named atrazine in its 2025 report. Then the follow-through thinned. Agriculture's voice inside the administration worked to soften the language, the EPA keeps defending it, and the only number that moved, the water limit, went the wrong way. A movement at war with itself.

  10. #10

    When a chemical is banned across Europe, flagged as a probable carcinogen, and defended by a company that hunted its critic, ask who the system is protecting. Full essay, fully sourced, here: malone.news/p/the-frog-whi…