Workplace Health & Safety Queensland recently issued a safety alert following an incident in which a truck driver was exposed to a fumigant that produced phosphine gas.
The truck driver began feeling very unwell after transporting grain to a feedlot with his semi-trailer.
For reasons yet to be established, it appears that during the transportation he was exposed to a fumigant that produced phosphine gas which is commonly used to control insect infestations in grain.
While investigations are continuing, the safety alert noted fumigants, including aluminium phosphide, are used in the agriculture industry to kill pests such as grain weevils.
Aluminium phosphide is a solid fumigant that reacts with moisture in the air to release highly toxic phosphine gas.
If the manufacturer’s directions aren’t followed, there is a serious risk to those who transport or store the grain.
The alert said reducing timeframes or applying aluminium phosphide fumigants in poorly-sealed containers, such as a semi or B-double trailer covered with a tarpaulin, will not effectively control pests and creates a serious risk to people from any remaining phosphine gas.
Phosphine gas is toxic when breathed in at concentrations approaching or exceeding the workplace exposure standard of 0.3ppm using a time-weighted average over an 8-hour workday, or 1ppm as a 15-minute short term exposure limit.
Early symptoms of exposure may include:
The alert said exposure to high levels of phosphine gas can cause damage to the kidneys, liver and heart, as well as pulmonary oedema (fluid in the lungs), convulsions and death. Phosphine gas is heavier than air and hazardous concentrations can develop quickly in enclosed, poorly ventilated, or low-lying areas.
The alert recommended developing a safe system of work for fumigation activities: