Chemical giant Bayer has been forced on the defensive after a second court ruling that one of its most popular products is associated with cancer.

Key points: Lawyers say the decisions coming out of the US are heartening for plaintiffs in Australia, with an influx of people making enquiries

Lawyers say the decisions coming out of the US are heartening for plaintiffs in Australia, with an influx of people making enquiries Farmers say a ban on glyphosate would be devastating and would reduce crop yields by two-thirds

Farmers say a ban on glyphosate would be devastating and would reduce crop yields by two-thirds The Cancer Council wants more research into the potential risks, but says the public needs to maintain faith in the present science

A Federal District Court jury in San Francisco found in favour of 70-year-old Edwin Hardeman, who claimed glyphosate, marketed as Roundup, was a factor in him developing non-Hodgkin's lymphoma.

It comes just months after a former school groundskeeper was awarded $289 million for the same cancer he said stemmed from his use of the chemical, an amount later reduced on appeal.

Bayer has vowed to appeal, saying the verdict was reached on shaky scientific evidence it sought to exclude before trial.

Legal ramifications

Maurice Blackburn Lawyers' Queensland principal Jonathan Walsh said it was a bellwether case for hundreds of others in the same jurisdiction.

While the impacts were less certain for local courts, similar expert evidence could form part of Australian court cases.

"These decisions coming out are heartening for plaintiffs here in Australia, to continue pursuing legal entitlements," Mr Walsh said.

"The expert evidence used in the US is comparable and can be used in Australian cases; however, standards could make a similar judgement more difficult.

Used on broadacre cropping operations, proponents say glyphosate has boosted production while reducing water loss and carbon emissions. ( Kendall Jackson )

"The standard to prove that glyphosate caused these injuries, it is different, the requirement for expert evidence in order to satisfy that test of legal causation appears to be a bigger challenge."

Mr Walsh said the decision could lead to more interest from those who blamed the chemical for their cancer.

"Around the first decision from last year, we certainly had an influx of enquiries around that time," he said.

Glyphosate critical: farmers

Chairman of Grain Producers Australia and western Victoria farmer, Andrew Weidemann, has been using glyphosate for decades and said he had no concerns about its safety.

"It's been approved as safe by regulatory authorities right around the world; there's no proof that this isn't a safe product to use," he said.

Mr Weidemann said he was concerned that the cases being brought against Monsanto could see glyphosate withdrawn from shelves, which he said would be a crushing blow for agriculture.

"I would think we would be back to a third of our production overnight if we weren't able to use it," he said.

"We would really struggle to produce enough food to feed a growing world population."

Matthew Cossey, CEO of Croplife Australia, which represents agricultural chemical companies, said the findings of the US jury should not be extrapolated globally.

Wimmera farmer Andrew Weidemann says pre-glyphosate, crop yields were as much as two-thirds lower. ( ABC News: Rachel Carbonell )

"We need to separate what is a medico-legal case in a Californian civil litigation matter to the actual independent regulatory assessment," he said.

"If you look at the statements by a range of independent experts, all have been clear there is absolutely no scientific connection between the normal use of glyphosate and any cancer risk.

"The reason glyphosate is so successful and used not just in Australia but globally is because it's so effective and safe, so that's the irony here."

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CEO of rural lobby group WAFarmers, Trevor Whittington, said a ban could be disastrous for farmers and the court outcome required careful handling.

"First and foremost is to be engaging with our state government and our community, so we don't end up going down the same path of the US and France and overreacting," he said.

"We need to build that community confidence that it is safe, if well handled and it's also an essential part of our cropping rotation."

As much as 8.6 billion kilograms of glyphosate has been used globally since it was introduced in 1974. ( ABC News: Neale Maude )

But a director of Gene Ethics, a community network concerned about genetically engineered crops and foods, rejected assertions the science was clear and overwhelming when it came to glyphosate.

Bob Phelps believed, before being acquired by Bayer, Monsanto massaged the science, misleading authorities about the chemical's safety.

"Regulators and the companies themselves have been relying on company-generated data … Monsanto has been misleading regulators and the public for the past 50 years," he said.

More study needed

The Cancer Council has called for more research into specific potential risks from the chemical, but urged the public to maintain faith in the present science.

CEO Sanchia Aranda said the non-specific research cited by the plaintiff's lawyers required more attention.

"It is strong enough to suggest the association with non-Hodgkin's lymphoma is worth investigating; we would like to see the global community do more work," Professor Aranda said.

"It's a specific need in those people who are exposed on a regular basis in the context of their work.