Major class action thrown out as Federal Court finds insufficient evidence to prove weedkiller Roundup causes cancer

There is insufficient evidence to prove the controversial weedkiller Roundup causes cancer, the Federal Court has ruled.

Roundup’s parent companies Monsanto and Bayer were taken to court in a major class action, with hundreds of Australians claiming their exposure to the product’s active ingredient, glyphosate, caused non-Hodgkin lymphoma.

After hearing evidence in a lengthy trial, Justice Michael Lee said on the balance of probabilities, the plaintiffs failed to prove that the products caused cancer.

Justice Lee acknowledged there were mixed views in the scientific community about the risks of Roundup, and said further research could provide a more definitive answer.

The judge said none of the scientific studies presented at the trial led him to conclude there was “clear and compelling” evidence that glyphosate caused cancer in mammals.

The lawsuit against Monsanto and Bayer has now been dismissed.

Glyphosate has been hailed as transformative for farmers, weed sprayers and gardeners but there has also been widespread debate about its safety.

About 500 glyphosate products are currently approved in Australia.

Latest in a string of legal battles

The current lawsuit, brought by plaintiff Kelvin McNickle and backed by Maurice Blackburn, alleged the weedkiller was carcinogenic and that its manufacturers were negligent about risks the product posed to customers.

Mr McNickle, who is in his early 40s, developed non-Hodgkin lymphoma after two decades of exposure to glyphosate while working for his family’s vegetation management business in Queensland.

About 800 others joined Mr McNickle’s class action lawsuit.

Outside court on Thursday, Bayer’s crop science director Warren Inwood hailed the result as a win for Australian farmers.

“These products underpin sustainable farming systems and support farmers in doing what they do best — putting food on the tables of Australians every day,” he said.

In a statement, Maurice Blackburn said it was “carefully reviewing the judgement”, stopping short of declaring it would lodge an appeal.

Roundup’s manufacturers, who insist the product is safe, have been locked in legal battles with class action litigants in Australia since 2019.

Bayer has also been the subject of numerous legal cases in the United States.

In 2020, it paid out $US10.9 billion ($16.6 billion) to settle 95,000 Roundup lawsuits.

However, Bayer claims it has won 14 of its previous 20 cases at trial, and has vowed to appeal recent US losses where it was ordered to pay out a combined $1.1 billion in damages.

In 2015, the International Agency for Research on Cancer said glyphosate was “probably carcinogenic to humans”, based on what it described as “limited” evidence of cancer in people.

But two years later the local regulator, the Australian Pesticides and Veterinary Medicines Authority (APVMA), said it believed the chemical was not cancer-causing from its analysis of scientific research.

In November 2023, the European Commission voted to approve glyphosate usage for another decade, although not all members states agreed to back the proposal.

Andrew Weidemann, the southern director of Grain Producers Australia, said he had used the herbicide for nearly 40 years and believed it was safe.

“It’s one of the greatest tools invested in my time of farming,” he said.

If Roundup was banned, Mr Weidemann said he feared for the future of food production.

The APVMA said it noted Justice Lee’s decision and would continue to monitor the science around glyphosate.

The regulator said it would take “appropriate action” if new evidence showed the chemical posed a risk to the community, industries or environment.