Australia has defied global trends by retaining the use of paraquat, a highly contentious herbicide linked to Parkinson's disease, despite being banned or heavily restricted in over 70 countries. The decision, made by the Australian Pesticides and Veterinary Medicines Authority (APVMA), follows a lengthy review of hundreds of scientific papers on the chemical's safety.
While the regulator acknowledged evidence of potential health impacts on farm workers, birds, and mammals, it stated that its review did not establish a definitive causal link between paraquat exposure and Parkinson's disease. However, this conclusion has been disputed by Parkinson's groups, scientists, and neurologists worldwide, who argue that a correlation exists based on robust epidemiological studies.
The new restrictions on paraquat use aim to reduce exposure risks significantly, including phasing out backpack sprayers, requiring enclosed mixing and loading systems, and mandating enhanced personal protective equipment for users. The maximum application rate will also be substantially reduced from 1,150 grams per hectare to 231 grams per hectare, with a higher rate permitted only for technology-assisted spot spraying.
Australia's decision is at odds with the European Union and the UK, which banned paraquat in 2007 following a lawsuit that found Syngenta had not adequately established its safety. An investigation by The Guardian in 2022 revealed internal Syngenta documents from the 1970s indicating reservations about paraquat's chronic effects, despite public assurances to the contrary.
US regulators also permit ongoing use with tighter controls, but Parkinson's researchers in Australia argue that their country is out of step with prevailing scientific evidence. Professor Wes Thevathasan, a Melbourne neurologist, pointed to multiple epidemiological studies suggesting a threefold increase in risk and highlighting the global consensus on the link between paraquat exposure and Parkinson's development.
The APVMA's chief executive, Scott Hansen, defended the decision, citing the regulator's preference for a clear answer on causation. However, the ruling is unlikely to quell the ongoing controversy surrounding paraquat and Australia's approach to regulating agricultural chemicals.