For the first time ever, Australian grain growers have full-scale trial data to show what a purpose-built phosphine fumigation system with recirculation and ventilation actually delivers in the field.
In March 2026, Action Steel ran its first commercial-scale trial using FumoFlow, their new patent-pending grain shed fumigation system, on a shed storing 5,420 tonnes of wheat. The trial ran for 15 days across 12 independent monitoring probes, placed at both surface and floor level to capture readings across every part of the shed.
What the data showed
Phosphine concentration peaked at an average of 1,068 ppm across all 12 probe locations within 49 hours of introduction.
Every probe exceeded 550 ppm within that window, and held above it for the full 7-day period. Every probe also held above 200 ppm for the full 10 days. Not one dropped below either threshold during the required exposure window.
For context, 550 ppm maintained for 7 days is the commonly referenced target for addressing phosphine-resistant insect strains. 200 ppm for 10 days covers susceptible populations at all life stages.
FumoFlow met both thresholds, consistently, across every probe location throughout the full exposure window.
Why gas distribution matters
In a passively sealed shed or silo, phosphine can pool and stratify. Concentrations near the fumigant source run high. Readings further away, particularly at floor level, often fall short. That is where failed fumigations start.
FumoFlow actively recirculates gas through the grain mass from the point of introduction. In this trial, probes at floor level and furthest from the fumigation boxes returned concentrations well above threshold, consistent with readings near the source.
The trial demonstrated uniform gas distribution across the full 5,420 tonnes of grain, from surface to floor, and from the point of introduction to the furthest edges of the stack.
Ventilation in two days
Once fumigation was complete, the FumoFlow fans switched to ventilation mode. The shed reached safe re-entry levels in two days.
Passive ventilation after tarp removal takes considerably longer and requires staff on site to start the process. With FumoFlow, the entire ventilation cycle is managed from outside the shed.
With tighter phosphine Workplace Exposure Limits coming into effect in December 2026, reducing the 8-hour TWA from 0.3 ppm to just 0.05 ppm, that speed and control matters. It is a compliance advantage, not just an efficiency one.
What this means for grain growers
Phosphine resistance is increasing. Regulatory requirements are tightening. And the cost of a failed fumigation, whether that is rejected grain at receival or a re-infestation, is real.
For the first time ever, you have trial data from a full-scale commercial shed to guide that decision.
The results are in. FumoFlow delivers.
FumoFlow was developed over 18 months in consultation with growers and leading fumigation contractors. The results from the first full-scale trial suggest the work was worth it.
Visit fumoflow.au or call 1800 68 78 88 to find out more.
FumoFlow is a product of Action Steel, The Big Shed People.
