Background and ongoing management

The investigation into PFAS contamination coming from RAAF Base Williamtown is complete, and the NSW Government is providing long-term advice to the Williamtown community.

What is PFAS?

PFAS (per- and poly-fluoroalkyl substances) are a group of manufactured chemicals that have been used as fire retardants since the 1950s, and in a range of common household products and specialty applications across Australia and internationally. This includes non-stick cookware; fabric, furniture and carpet stain protection applications; food packaging; some industrial processes; and some types of firefighting foam.

PFAS are considered an emerging contaminant and research is still being undertaken globally to understand their long-term effects. There is no consistent evidence that PFAS is harmful to humans, but because these chemicals take a long time to break down in humans and in the environment, the NSW Government has adopted a precautionary approach to managing PFAS across the state.  

The NSW EPA is investigating sites across NSW to better understand the extent of PFAS use and potential contamination.


On the 3 September 2015, the NSW Government announced that PFAS contamination had been detected both on and offsite at the Department of Defence RAAF Base at Williamtown. A full environmental investigation by the Department of Defence was initiated, which was conducted to determine the full extent of contamination, and any risks to human health and the environment.

The NSW Government released a map of the Williamtown Investigation Area and precautionary advice for residents to minimise their exposure to PFAS from the RAAF Base. This included fishing closures in Fullerton Cove and upper Tilligerry Creek. These closures have since been lifted and replaced with dietary advice for seafood and fish produce.

An Expert Panel of technical experts in contamination and health was convened, led by the NSW Chief Scientist and Engineer, Professor Mary O’Kane AC. The panel was tasked with exploring the nature and extent of the contamination and recommending next steps. Two working groups - the Human Health Risk Assessment Group and the Water Working Group - were developed to provide additional expertise and assistance.

These Groups provided technical guidance to the Department of Defence during the investigation, as well as advising the NSW Government on issuing and updating precautionary advice, and re-defining the Investigation Area as new information became available.

A Community Reference Group (CRG) was also convened to ensure that the residents were provided with ongoing updates and advice to the community during this process.

In August 2016, the Department of Defence released the first Human Health Risk Assessment (HHRA) and Environmental Site Assessment (ESA) Reports. These reports were reviewed by the NSW Government and Expert Panel, confirming that the precautionary advice, fishing closures and Investigation Area were still appropriate and should remain in place. Drinking contaminated groundwater was identified as the major exposure pathway, and a number of data gaps were identified. The NSW EPA requested the Department of Defence to carry out additional testing and sampling. 

The Department of Defence released the final HHRA and ESA in December 2017, concluding the investigations. The Expert Panel reviewed the HHRA and recommended some changes to better reflect the level of exposure of residents to the contamination in certain areas. This resulted in updated precautionary advice and the development of a new Williamtown Management Area. The Department of Defence released the Ecological Risk Assessment in October 2018, which looks at the potential risks to plants and animals.

The Expert Panel continues to work on other PFAS-related sites in NSW.

Ongoing management

As the investigation phase is complete, the NSW Government has provided long-term advice to the Williamtown community.

The Department of Defence is currently developing the Williamtown PFAS Management Area Plan (PMAP), which includes an Ongoing Monitoring Plan (OMP). The PMAP will outline the actions that will be taken over the coming years to manage the PFAS contamination. The OMP will monitor the levels of PFAS in the area, to determine if these actions are effectively reducing the PFAS contamination.

The EPA, Expert Panel and Water Working Group will continue to review any reports released by the Department of Defence, to ensure they are scientifically sound, and that the Williamtown Management Area Map and precautionary advice remain appropriate.

Williamtown Management Area

The Williamtown Management Area was developed following

  • a significant amount of new data from further testing carried out by the Department of Defence in October 2016, requested by the NSW Government.
  • an increased knowledge of the surface and groundwater in the Management Area
  • modelling of the movement of PFAS into the future

The Williamtown Management Area, comprises three zones:

  • Primary Management Zone this area has significantly higher levels of PFAS detected and therefore, the strongest advice applies.
  • Secondary Management Zone – this area has some detected levels of PFAS. 
  • Broader Management Zone – the topography and hydrology of the area means PFAS detections could occur now and into the future.  

Each zone has tailored precautionary advice for residents to minimise exposure to PFAS originating from the RAAF Base Williamtown. 

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