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Legionella risks from work with potting mix and compost

Legionella bacteria, potting mix and compost

Legionella bacteria are found in the environment. Human infection is most commonly caused by:

  • Legionella pneumophila – found in man-made water systems such as cooling towers(PDF, 472.21 KB) and spas.
  • Legionella longbeachae – found in potting mix and compost.

Infection with Legionella bacteria can cause:

  • Legionnaires' disease –a severe respiratory illness with pneumonia.
  • Pontiac fever –a mild influenza-like illness without pneumonia.

People who work with potting mix and compost may be exposed to Legionella longbeachae bacteria. Infection can occur from breathing in dust and aerosols that contain the bacteria and from hand to mouth contact.

Most people who are exposed to Legionella longbeachae bacteria do not become ill. The risk of illness increases for workers over 50 years of age, who smoke, have a weakened immune system or a chronic disease (e.g. chronic heart, lung or kidney disease, diabetes or cancer).

If a person is diagnosed with a Legionella longbeachae bacteria infection because of their work, this must be notified to Workplace Health and Safety Queensland.

Who is at risk?

Workers who work with potting mix, compost and similar materials such as mulch, decomposing plant materials and gardening soil are at increased risk of infection. At risk workers include:

  • gardeners, horticulturalists and nursery workers
  • workers who work with green waste
  • workers who manufacture potting mix and compost.

If a worker who works with these materials becomes sick with a respiratory illness, they should tell their doctor about their work.

Managing exposure

Eliminating exposure is the most effective way to protect workers, however this may not always be possible. Where the risk cannot be eliminated, it must be minimised.

  • Minimise exposure to dust and aerosols, for example:
    • wet potting mix and compost before handling, during use and when cleaning up to keep it moist
    • open bags of potting mix carefully and direct the opening away from the face
    • handle potting mix and compost in a well-ventilated area
    • when emptying bags of potting mix and applying compost, avoid shaking the bag and keep the product close to the ground
    • avoid using water under high pressure on potting mix and compost
    • wear a properly fitted(PDF, 883 KB) particulate respirator (e.g. disposable half-face respirator with a P1 or P2 filter) when handling potting mix and compost and turning over compost heaps.
  • When handling potting mix and compost:
    • wear gloves
    • avoid touching your face
    • don't eat, drink or smoke.
  • Wash hands thoroughly with soap and water:
    • after handling potting mix and compost
    • before eating, drinking and smoking
    • after removing gloves.
  • Store bagged potting mix in a cool, dry place and out of direct sunlight.
  • Clean and cover cuts, abrasions and other non-intact skin with a dry dressing.
  • Wash work clothes regularly.
  • Read the warning label on commercial potting mixes and follow the manufacturer' instructions.

More information

Contact Workplace Health and Safety Queenslandon 1300 362 128 for information on work with potting mix and compost. If a person contracts an infectious disease at work, this must be notified to Workplace Health and Safety Queensland.

Contact Queensland Health on 13HEALTH (13 43 25 84) for information about Legionnaires’ disease. Seek advice from your doctor or local public health unit if you have concerns about possible exposure to Legionella bacteria.

Last updated
17 March 2020

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