Safety warning issued after truck driver exposed to phosphine gas

The following article is a news item provided for the benefit of the Workplace Health and Safety profession. Its content does not necessarily reflect the views of the Australian Institute of Health & Safety.
Monday, 23 August, 2021 - 12:30
Policy & legislation

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:

  • respiratory problems, including coughing
  • double vision, dizziness and headaches
  • fatigue
  • gastrointestinal disturbances such as pain, nausea, vomiting and diarrhoea.

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:

  • Store canisters correctly to prevent deterioration of the tablets.
  • Ensure fumigation is conducted in well-sealed enclosures and fumigation and ventilation periods are followed.
  • Allow only qualified workers to use aluminium phosphide while on the farm and engage a licensed pest management technician to fumigate products that have left the farm. Users must hold the following national units of competency:
  • Where fumigation is a routine practice, it is recommended to have equipment available and calibrated to measure the concentration of phosphine.
  • Make and keep records of agricultural chemical applications and worker training.
  • Provide workers with personal protective equipment (PPE) required by the product label.
  • Provide workers with information, training and instruction in the proper use and wearing of PPE, and the storage and maintenance of PPE.
  • Ensure PPE is maintained, repaired and replaced so that the equipment remains clean and hygienic, and in good working order.