Residents around the RAAF base at Williamtown, north of Newcastle, are being told to take precautions after the discovery of firefighting chemicals in water.
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were historically used in fire-fighting foams.
The chemicals have been found in some surface water, groundwaters and in small numbers of fish around Tilligerry Creek and Fullerton Cove at Port Stephens.
As a precaution, authorities are closing commercial and recreational fisheries and the oyster harvest for up to a month in both bodies of water.
The chemicals were used at the base during training and operations before the Department of Defence changed its policy in 2008.
The Environment Protection Authority (EPA) said the chemicals have been used in fire-fighting and fabric treatments around the world and do not break down in the environment.
It is not known whether the chemicals affect human health, but the EPA said “the potential for adverse health effects cannot be excluded”.
“While at this stage any risk to human health appears to be low, the NSW Government is taking a precautionary approach to this preliminary advice and is working with the Department of Defence to determine the extent and potential impact of these offsite chemicals,” it said in a statement.
Local residents are advised not to drink bore water and not to eat fish caught in the area or eggs from backyard chickens.
The EPA said there was no risk to town water supply.
Residents shocked at contamination warning
Lindsay Clout is the president of the Fullerton Cove residents action group.
He said he was shocked to hear of the contamination warning and said there had been concerns about the base for years.
“There has been anecdotal information in the area for some time that dangerous chemicals had been disposed off and buried in the ground in the Williamtown area, but it was very difficult to get any information about this,” he said.
“I’m just staggered the information has come out.”
In a statement, the Department of Defence said it was “committed to working with other Federal and State government departments to further investigate the possible human and environmental impacts associated with the historical use of fire-fighting foams.”
“The health and safety of people who reside near our bases and Defence personnel who work, or have worked, at these bases is a high priority for Defence,” it said.
“Despite extensive research, scientific studies into the possible human health impacts are inconclusive.”
The EPA said it would keep residents informed and a public meeting would be scheduled shortly.