Paraquat in Australia: why the weedkiller is still allowed, the Parkinson's debate, and the Senate inquiry explained

By The Rundowns News Desk · Published 1 November 2026

Paraquat, one of Australia's most widely used knockdown weedkillers, remains legal after the national chemicals regulator finished a review that ran for close to three decades. It now comes with much tighter limits, and the decision is being examined by a Senate inquiry. This week the regulator's chief executive was questioned at Senate estimates about how it weighed evidence on Parkinson's disease. Here's what changed, what each side says, and how to have your say before submissions close on 18 November.

What happened this week

At a Senate budget estimates hearing on Tuesday, independent ACT senator David Pocock questioned Australian Pesticides and Veterinary Medicines Authority (APVMA) chief executive Scott Hansen for about 30 minutes over the paraquat review, The Guardian reports. Pocock said the review relied partly on studies funded by the manufacturer Syngenta and on studies that tracked effects over periods as short as 30 days. He argued that Parkinson's can take "years to decades" to appear. Hansen defended the process, saying it weighed all the studies and considered potential bias from both industry and health-sector researchers.

The exchange happened at estimates because Pocock's push for public hearings in the inquiry itself was voted down 26 to 15, with Labor, Liberal and National senators opposed, according to Grain Central. The Guardian also reports the motion was defeated.

What the regulator actually decided

The APVMA's final decision, released on 23 June 2026, covers both paraquat and the related herbicide diquat. Both stay registered, with these changes:

• The maximum application rate is cut to 231 grams per hectare, down from 1,150 g/ha. A higher rate is allowed for technology-assisted spot spraying, capped at 30% of the total area.
• Backpack sprayers are phased out.
• Enclosed mixing and loading systems are required for all uses, along with enhanced personal protective equipment.
• New label conditions apply to products made from 23 June. Existing stock is phased out over two years.

The APVMA says these limits are driven by the acute poisoning risk to people handling the chemicals, which are Schedule 7 poisons, and by risks to birds and mammals that forage in treated areas. The Guardian also reports a phase-out of use on certain crops, including sugar cane.

The Parkinson's question

This is the core of the dispute.

• The regulator's position: the APVMA found that "the weight of evidence does not show that paraquat exposure through approved uses increases the risk of developing Parkinson's disease". Its neurotoxicity report says it screened 156 references cited in public submissions and considered 21 newer papers in detail. It concluded, in line with a 2019 US Environmental Protection Agency review, that the evidence does not convincingly show a direct causal link.
• The critics' position: neurologists in Australia and overseas say the review was too narrow. The Guardian reports criticism that it left out a landmark 2011 study. That study and later research associated paraquat exposure with 2.5 times the odds of developing Parkinson's, or 4.5 times for people not wearing protective clothing. US neurologist Michael S Okun, of University of Florida Health, wrote to the inquiry that "in medicine, we do not wait for every uncertainty to disappear before acting". Parkinson's Australia's submission calls for an immediate ban.
• The manufacturer's position: Syngenta has long said there is no established link between paraquat and Parkinson's (The Guardian).

Association isn't the same as proven causation, and that gap is exactly what the regulator and its critics disagree on. The inquiry is meant to test how the APVMA handled that evidence.

"Banned in 70 countries": what that means

Pocock told the Senate that paraquat is banned in more than 70 countries, including China, and The Guardian reports the same figure. The APVMA's Hansen argued that the European Union's ban, which covers 27 countries, stemmed from perceived gaps in regulatory frameworks rather than health findings. Treat the headline number as a count of bans, not a count of countries that found a Parkinson's link.

Why farmers are worried too

For grain and cane growers, paraquat is a dependable knockdown herbicide. It supports no-till farming and helps against weeds that have grown resistant to other chemicals. Western Australian grain growers told the inquiry that lower rates would mean more cultivation, which affects soil quality and carbon storage. They asked that any further changes be evidence-based and phased in with practical help (The Guardian). Grain Central reports that Grain Producers Australia, GrainGrowers and state farming bodies opposed the inquiry, saying it could undermine the regulator's independence.

Supply is also shrinking. Syngenta announced in July that it will exit all paraquat products in Australia and New Zealand. It cited "commercial grounds": generic competition, its local formulation partner stopping production, and the cost of compliant storage. It says it will follow the APVMA's sell-out and use-by timelines. The Guardian links the exit to the new restrictions. Other generic paraquat products remain registered under the new conditions.

The Senate inquiry: what it covers and how to have your say

The Senate referred the APVMA's June decision to the Rural and Regional Affairs and Transport References Committee on 8 September, with support from the Coalition and the Greens (ABC Rural). Its terms of reference include:

• the scientific evidence the APVMA considered, and how adequate, transparent and independent its process was
• current evidence on paraquat and Parkinson's and other neurological conditions
• the impact on farmers, farm workers, regional communities, golfers and others who may be exposed
• how other countries regulate paraquat, and whether Australia's framework needs changes

Submissions close 18 November 2026. The deadline was extended from 22 October (Grain Central), and the inquiry is listed on the Parliament of Australia's open submissions page. The committee is due to report by the first sitting day of 2027.

What's next

• 18 November: public submissions close.
• Early 2027: the committee reports. It can recommend changes but can't itself cancel a chemical's registration. That power sits with the APVMA. (Our reading of the process. Check the committee page for the formal position.)
• By mid-2028: the two-year phase-out of old-label stock ends, based on the 23 June 2026 decision date.

If you use paraquat or diquat, check your product's label and the APVMA decision for the new handling rules. Don't rely on older labels.

This article is general information, not medical, legal or agronomic advice. If you're worried about past chemical exposure, talk to your GP.