New rules for workplace exposure to dust, chemicals and gasses come into effect on December 1, but mine and farm groups say they are not practical or measurable.
Safe Work Australia formed the new rules, but enforcing the limits will be up to each state.
Farmers and miners in Western Australia are nervous about new workplace safety rules that will reduce accepted exposure levels of dust and certain chemicals from December 1.
New rules set by Safe Work Australia will reduce the safe exposure limit for hundreds of dusts, fumes and chemicals found in Australian workplaces.
West Australian Grain Group chair Alastair Falconer said farmers were alarmed SWA's accepted exposure limit for the fumigant phosphine will be reduced by 80 per cent.
Mr Falconer said the grain industry relied on phosphine to keep insects out of stored or exported grain, but said the new rule "almost renders phosphine unusable".
In a statement, Safe Work Australia said workplace exposure limits were used to protect workers and the revised workplace exposure limits reflect current scientific evidence and independent expert advice.
Safe Work said it conducted public consultation in 2019-2021, and the new limits were agreed by work health and safety ministers and published in April 2024 for implementation on December 1, 2026.
In August, WorkSafe Victoria said it would delay workplace exposure limits for 15 airborne contaminants, including phosphine, until December 1, 2029.
Association of Mining and Exploration Companies chief executive Warren Pearce said Safe Work had taken a "blanket" approach, which was not always practical to carry out.