Legionella and garden soils

Commercial garden soils which include packaged potting mixes and bulk soil supplies have been associated with several cases of Legionnaires’ Disease in WA, as a result of exposure to the bacteria Legionella longbeachae.

How Legionella longbeachae are spread is uncertain, but it is thought that they are breathed in or spread from hand to mouth. The bacteria can remain on hands contaminated by handling potting mix and other garden soils.

Garden soils, as defined by the Garden Soils Regulations, include:

  • potting mixes
  • gardening soils
  • mulches
  • composts
  • soil conditioners.

Package, in relation to garden soil, means anything that contains or surrounds the garden soil, whether or not the garden soil is completely enclosed.

Currently, no strategies are available to control or eliminate Legionella longbeachae growing in commercial garden soils. Soil in the natural environment may still present a risk when people are working in their gardens.

Safety precautions

Preventative strategies for this disease are limited to educating the community on the safe use of garden soils, which includes publishing health warnings on bagged materials and providing signage near bulked products. Such warnings attempt to inform the consumer to take precautionary measures when handling garden soils.

These recommendations include:

  • using a face mask
  • wearing gloves
  • avoiding inhalation of dust and aerosols and
  • washing hands after using the material.

This public health risk is currently managed under the Health (Garden Soil) Regulations 1998, (Garden Soils Regulations) which requires warning labels to be included on packaged materials or for signage to displayed in prominent locations at bulk soil suppliers.


Updates to commercial garden soils regulations

As part of the implementation of the Public Health Act 2016 all regulations under the Health (Miscellaneous Provisions) Act 1911, as well as a number of provisions within the Act, have been reviewed to determine which public health risks should continue to be regulated under the framework provided by the Public Health Act or alternatively managed in other ways such as by other legislation or a guideline.

Guideline for commercial garden soils

Given the overall risk to public health from commercial garden soils is considered low, the Health (Garden Soil) Regulations 1998 (WA) will be repealed on 4 June 2024 and replaced with a guideline.

Implementation of the new Guidelines will commence on Tuesday 4 June 2024.

The guideline be the primary guidance material for those managing the public health risks associated with commercial garden soils and provides information and guidance on best industry practice for managing the public health risks associated with commercial garden soils.

The general public health duty, specified in Part 3 of the Public Health Act 2016, requires that all persons and businesses “must take all reasonable and practicable steps to prevent or minimise any harm to public health that might foreseeably result from anything done or omitted to be done by the person”. The Guideline may be used to clarify the application of the general public health duty and provide information on the “reasonable and practicable steps” that should be taken to prevent or minimise harm to public health.

Important updates and information you need to assist you through this transition can be found on this page.

For further information you can contact the Environmental Health Directorate at publichealthact@health.wa.gov.au.

Last reviewed: 08-03-2024
Produced by

Environmental Health Directorate