Australia’s National Farmers’ Federation has rejected the finding of a US court that the weedkiller Roundup causes cancer, saying it set a “reckless precedent” that could harm agriculture.

On Monday, Greenpeace urged the Australian government to start restricting the sale of Roundup – which is widely available in supermarkets and hardware stores – after a Californian court found it caused the cancer of a terminally ill man.

The jury ruled that Dewayne Johnson, a school groundskeeper, developed non-Hodgkin lymphoma due to regularly using Roundup. It also found that the manufacturer, Monsanto, knew of the product’s potential health risks, and acted “with malice or oppression” by failing to warn users.

The active chemical in Roundup – glyphosate – has been classified as “probably carcinogenic” by the World Health Organisation but is still approved for use in Australia and the US.

On Tuesday, the NFF said the US court decision was “in blatant ignorance” of science.

“No other herbicide has been tested to the lengths that glyphosate has,” the NFF president, Fiona Simson, said. “After four decades of evaluations, no regulatory agency in the world considers glyphosate to be carcinogenic.”

She said glyphosate – the world’s most common herbicide – had an environmental benefit.

“Through the use of glyphosate, farmers are able to practise minimum tillage – protecting soil structure and nutrients and ultimately increasing the storage of soil carbon,” she said.

Australia’s chemical regulator, the Australian Pesticides and Veterinary Medicines Authority, classifies Roundup as safe.

“The APVMA is aware of the decision in the Californian superior court,” a spokesman said on Monday. “APVMA approved products containing glyphosate can continue to be used safely according to label directions.”



Paul Pharoah, professor of cancer epidemiology at the University of Cambridge, said the court’s finding did not mean that glyphosate necessarily caused cancer.

“These medico-legal cases are always difficult to make because the concepts of risk and cause in a scientific sense are different to those concepts in a legal sense,” he said.

“The epidemiological evidence that glycophosphates are associated with an increased risk of lymphoma is very weak ... From a purely scientific point of view I do not think that the judgement makes sense.”

Ian Rae, a professor of chemistry at the University of Melbourne, said the risk of developing cancer from Roundup was “very, very low”.

He said the categorisation of glyphosate as a carcinogen was based on very high exposure levels in workplaces.

“The basic measure is that if the exposure is low, there is very little risk ... I don’t think there is a case for stopping using it at all.”

Monsanto’s vice-president, Scott Partridge, has also insisted that Roundup is safe, and the company intends to appeal against the decision.



But Friday’s ruling in the US was scathing of Monsanto’s behaviour.



Johnson’s lawyers produced internal Monsanto emails that they said proved the corporation knew of the risks, ignored expert warnings, “ghostwrote” research that was favourable and targeted academics who spoke up against Roundup.

They alleged that Monsanto “fought science” for decades to have the product’s health risks downplayed.

Patridge said the internal emails had been taken out of context.

Johnson, a 46-year-old father of three, was awarded US$289m in damages and compensation. He worked for a school district near San Francisco, spraying herbicides on weeds for several hours a day. Doctors say he has months left to live.

Another trial against Monsanto is scheduled to begin in Missouri in the coming months.