Weed Spraying and Herbicide Application

Yes. Every Australian state and territory requires licensing for commercial herbicide application (spraying for fee or reward). The specific licence type varies: NSW requires a Ground Applicator Licence (5 years) from the EPA, based on ChemCert AQF3 training. Victoria uses an Agricultural Chemical User Permit (ACUP, 10 years) from Agriculture Victoria. Queensland requires an ACDC or Commercial Operator Licence from Biosecurity Queensland. WA requires a Pest Management Technician Licence from the Department of Health. Similar requirements exist in SA, TAS, NT, and ACT. The base training in most states is ChemCert AQF3 accreditation, which includes the unit of competency AHCCHM307 — Prepare and apply chemicals to control pest, weeds and diseases. Spraying without a valid licence is illegal and carries significant penalties.

The International Agency for Research on Cancer (IARC) classified glyphosate as Group 2A — "probably carcinogenic to humans" in March 2015, based on limited evidence of positive association with non-Hodgkin lymphoma. However, the Australian Pesticides and Veterinary Medicines Authority (APVMA) reviewed the IARC evidence and concluded that glyphosate does not pose a carcinogenic or genotoxic risk to humans when used in accordance with label directions. Glyphosate products remain registered for use in Australia. The key safety requirements are: follow label directions exactly, wear PPE as specified on the label and SDS (minimum: gloves, safety glasses, long sleeves), avoid skin contact and inhalation of spray mist, and wash hands thoroughly after use. Regardless of the regulatory position, minimising personal exposure through correct PPE and application technique is always prudent.

Temperature inversions are the single greatest spray drift risk factor. During an inversion, a layer of warm air sits above cooler air near the ground, creating a stable atmosphere that prevents spray droplets from dispersing upward. Instead, fine droplets remain suspended near ground level and can be carried laterally for kilometres by gentle air movement — far beyond the target area. Inversions typically occur from about 1.5 hours before sunset to 1.5 hours after sunrise, and are most common on calm, clear nights. Signs of an inversion include: very calm air (wind speed below 3 km/h), dew forming on surfaces, ground-level fog or mist, smoke or dust hanging close to the ground instead of rising, and unusual odours carrying long distances. Most herbicide labels now prohibit spraying during temperature inversions. If conditions suggest an inversion, do NOT spray — wait until the inversion lifts (usually indicated by rising air temperature and increasing wind activity).

Minimum PPE varies by product and activity. For routine spray application: chemical-resistant gloves (nitrile minimum, check SDS for material), safety glasses with side shields, chemical-resistant coveralls (long sleeves and legs), enclosed chemical-resistant footwear (gumboots or safety boots), P2 respirator (minimum for outdoor spraying), and sun protection. For mixing and loading concentrated chemicals: upgrade to chemical splash goggles (sealed), PVC or neoprene gauntlet gloves, chemical-resistant apron, and half-face respirator with organic vapour/particulate cartridge (Type A1P2). For Schedule 7 products (paraquat): full-face respirator, full chemical-resistant suit, sealed goggles, and gauntlet gloves. Always check the specific product SDS and label — some products have additional PPE requirements. Remember: wash hands BEFORE removing gloves, and launder contaminated clothing separately from household washing.

Herbicide ingestion is a medical emergency, particularly for paraquat (Schedule 7 Dangerous Poison — no antidote exists, lethal in small quantities). Immediate actions: Call 000 for ambulance AND call Poisons Information Centre on 13 11 26 (available 24 hours). Do NOT induce vomiting. If the person is conscious and able to swallow: rinse mouth with water and give small sips of water to dilute. If unconscious: place in recovery position, ensure airway is clear, and prepare for CPR. Provide the paramedics with: the exact product name and active ingredient, estimated quantity ingested, time of ingestion, and the Safety Data Sheet. Transport the product container and SDS with the patient to hospital. For paraquat ingestion specifically: even small amounts can cause fatal multi-organ failure — immediate emergency department treatment is critical. Time is the most important factor — do not wait for symptoms to develop before calling emergency services.

Spray drift management is a legal requirement under APVMA registration conditions and state EPA regulations. Key controls: check wind speed is between 3–20 km/h and blowing AWAY from sensitive areas (use an anemometer). Use drift-reducing nozzles (air-induction/venturi type) producing COARSE or VERY COARSE droplets — fine spray drifts much further. Keep boom height as low as practicable (within 50 cm of target for boom sprayers). Do not spray during temperature inversions (typically 1.5 hours before sunset to 1.5 hours after sunrise). Maintain label-specified buffer zones from property boundaries, waterways, and sensitive areas. Notify downwind neighbours before broadacre spraying. Record weather conditions before and during every application. If drift occurs: stop spraying immediately, notify affected property owners, document conditions, and report to your supervisor and state EPA if damage is suspected. Use wick/wipe application or shielded sprayers adjacent to sensitive boundaries for zero-drift application.