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Effluent Pond Operations -- Worker Drowns In Tractor Incident

  • Document Type: Guidance Note
    Keycode: web only
    Industry: Farming, 
    Category: Plant, 
    Publication Date: 21 July 2006
    Date First Published: 21 July 2006
    Summary: This Guidance Note highlights the need for farmers, farm contractors and the designers of effluent ponds to ensure that systems of work in managing effluent ponds are safe and risks are being controlled.

In Victoria in January 2004 a farm contractor drowned when the tractor which he was operating inadvertently slid into an effluent pond on a dairy farm. The death shows that there is significant danger when agricultural machinery such as tractors, pond stirrers and slurry tankers are operated in the vicinity of effluent ponds.

This Guidance Note is issued to highlight the need for farmers, farm contractors and the designers of effluent ponds to ensure that systems of work in managing effluent ponds are safe and risks are being controlled. This Guidance Note has been developed in conjunction with the Department of Primary Industries and in consultation with the Victorian Farmers Federation, Australian Workers' Union and stakeholders in the farming community.

How the incident happened
The farm contractor was operating a tractor which was powering an agitator (stirrer) to stir the contents of an effluent pond and break down the crust. The tractor was situated at the very top edge of the pond's bank.

The operator was either attempting to re-locate the tractor or attempting to stop the tractor from sliding rearwards when the tractor entered the pond and sunk to the bottom, a depth of approximately eight metres. The operator was unable to exit the tractor and there were no other people in the vicinity of the effluent pond to provide assistance.

Photo 1 -- Typical effluent pond on a dairy farm
Photo 1 -- Typical effluent pond on a dairy farm

Investigations by the State Coroner and WorkSafe Victoria have found that:

  1. Tractors are commonly used to power drive agitators and pumps as part of managing effluent ponds on dairy farms. Tractors are often in very close proximity to the edge of the effluent pond. It is usual for a contractor to be engaged to conduct the agitation and spreading of effluent, and often the farmer provides the tractor to power the agitator.
  2. It is known that the inside walls and edges of effluent ponds are extremely slippery due to sludge/spill and consequently these conditions affect the tractor tyres' traction.
  3. The tractor did not have a functioning four wheel drive system and the operator did not have knowledge of this fault. Further, the operator was not familiar with the type of tractor that was being used at the time.
  4. The operator was working alone and unsupervised at the time of the incident.
  5. There is no standard for the design of effluent ponds in Australia, nor is there a Code of Practice in the state of Victoria. However, the pond was originally designed to the specifications advised by the Department of Primary Industries.
  6. A Job Safety Analysis (JSA) was not completed prior to the commencement of work. The JSA may have disclosed the tractor's four wheel drive maintenance issue and, combined with the close proximity of the tractor to the pond's edge, the hazards may have been identified and the system of work could have been changed.


  1. Where practicable, farmers should seek to eliminate the need to use tractors in close proximity of the edge of effluent ponds. Systems of work might include combinations of the following:
    a) Using a small solar, wind or electric driven circulator mounted on a small pontoon to agitate the pond.
    b) Using electric pumps which are attached to sprinkler systems.
    c) Pumping effluent more frequently so the ponds do not form a crust.
    d) Using permanent fencing designed to prevent access to livestock, machinery and young children. Machinery access points should be provided for necessary pond maintenance and should be designed in consultation with the contractor.
    e) Engaging contractors with appropriate machinery and equipment.
    f) Using stirrers with a pushing motion and with a longer pole so that the tractor can be located at a safe distance from the outer edge of the pond.
    g) Using barriers or chocks to prevent the tractor from moving rearwards.
  2. It is imperative that farm machinery be regularly maintained according to manufacturer's instructions, and all operator controls should be clearly marked. Faulty machinery should not be used.
  3. Designers and manufacturers of effluent ponds should ensure that safety considerations form part of the advice in Effluent Management Plans. These Plans are provided to farmers and enable safe systems of work to be put in place. Safety considerations include the preferred pond site, the design/stability of the pond, banks and access points, the method of pumping and planning for ongoing maintenance. Ponds should never be sited near overhead power lines, trees or on hills.
  4. Workers, particularly those working with machinery, should not be working in isolation and there must be a level of supervision, training and instruction for the specific type of machinery and equipment which is to be used.
  5. Farmers and contractors should complete a Job Safety Analysis prior to starting a job and any changes to the pond design and the effluent level should be taken into account. All workers should be properly consulted and trained in safe operating procedures.

Photo 2 - Floating circulator coupled to a submerged impellor.
Photo 2 - Floating circulator coupled to a submerged impellor.

Legal responsibilities
Employers have responsibilities under the Occupational Health and Safety Act 2004 to provide and maintain, so far as is reasonably practicable, an environment that is safe and without risks to health. This duty extends to independent contractors and any employees of the independent contractor.

The Occupational Health and Safety Regulations 2007 require that hazards associated with the use of plant and equipment are identified and actions taken to control the risks. The regulations also require for plant to be maintained.

Acts and Regulations

  • Occupational Health and Safety Act 2004
  • Occupational Health and Safety Regulations 2007

Acts and regulations are available from Information Victoria on 1300 366 356 or order online at

View the legislation at Victorian Law Today at


Standards Australia

AS 2153:1997 -- Tractors and machinery for agriculture and forestry -- Technical means for ensuring safety (Parts 1 and 3).
Australian Standards are available from Standards Australia on 1300 654 646, or online at

Copies of standards can be obtained by contacting Standards Australia on 1300 654 646 or by visiting the web site at

Further information

WorkSafe Victoria publications

Department of Primary Industries publicationsAgriculture Notes AG0444 - Dairy Effluent: Building and Operating a Safe System (Feb 06)
Agriculture Notes are available for free from any DPI or online at Department Of Primary Industries, Information Series

EPA VictoriaView information regarding dairy effluent management at

Note: This guidance material has been prepared using the best information available to WorkSafe Victoria and the Department of Primary Industries. Any information about legislative obligations or responsibilities included in this material is only applicable to the circumstances described in the material. You should always check the legislation referred to in this material and make your own judgement about what action you may need to take to ensure you have complied with the law. Accordingly, the Victorian WorkCover Authority extends no warranties as to the suitability of the information for your specific circumstances.