The industry body representing Australian cotton growers has called for continuity in the regulation of the controversial chemical paraquat.
Paraquat is a widely used weedkiller that has been under review by the Australian Pesticides and Veterinary Medicine Authority (APVMA) for 27 years.
A proposed regulatory decision was released in August recommending tighter restrictions on the chemical's use and lower usage rates.
Public consultation on the proposal is due to close on Tuesday.
The chemical is widely used within Australia's cotton industry to prevent insect resistance to the genetically modified (GM) crop.
It is sprayed to defoliate the crop prior to harvest and to destroy the crop post-harvest — an essential step for growers to meet their legal responsibility in using the GM technology.
Doug McCollum, who prepared Cotton Australia's submission to the chemical regulator, stressed the importance of paraquat to one of Australia's most lucrative crops.
"It's basically revolutionised the way we manage weeds in cotton," he said.
Paraquat and Parkinson's
While Cotton Australia has called for sustained use of the chemical, others want to see it banned completely, citing evidence of its link to Parkinson's disease.
A drum of paraquat dichloride with a label describes the chemical as a toxic, corrosive liquid. (Supplied)
A Western Australia-based neurologist has amassed more than 40 signatures from colleagues in clinical neurology as part of his submission calling on the APVMA to take swift action.
Parkinson's is a progressive brain disorder that affects the nervous system. Symptoms generally develop over years and can affect movement, sleep, mental health and cognitive function.
The APVMA declined to be interviewed while the review was underway.
"This current review is in addition to the 2016 review of paraquat, where the APVMA requested an evaluation of the toxicology of paraquat by the Department of Health," the regulator said in a statement.
"At the time of the 2016 review, the epidemiological studies available did not find a robust association between paraquat exposure and Parkinson's disease."
A crop-duster sprays defoliant over a cotton crop in NSW. (ABC Rural: Lisa Herbert)
Concerns can be 'dealt with'
Mr McCollum said while Cotton Australia did not touch on Parkinson's disease in its submission, the industry body did support the regulator's recommendations in the draft review, which would limit the occupational exposure to paraquat.
"We have a really proud record in the cotton industry of adopting closed delivery systems and making sure that people who are using these products are doing so in a way that is safe," he said.
"There's technology out there to protect people using these chemical products and, if we can do that, the concerns around the toxicity of the product can be dealt with."
Cotton Australia says toxic chemicals such as paraquat can be safely managed. (Supplied: Alex Russell)
Cotton Australia also expressed support for further regulations aimed at reducing aerial spray drift of paraquat.
But Mr McCollum was concerned the chemical regulator would continue its current proposal to remove a number of current uses at high rates of paraquat application.
"If the draft review stays as it plans, there would be no way we could use any paraquat or paraquat diquat in cotton," Mr McCollum said.
He said the proposal would leave growers of dryland, or non-irrigated, cotton across Australia without a viable option to manage their crops.
"There would just be less cotton," Mr McCollum said.
The APVMA's final regulatory decision is expected in May 2025.