An additional 183 properties, included in the contamination zone when its footprint expanded 50 per cent in November last year, received letters in the mail from the NSW Valuer General.

Peter Payne, like most who spoke to the Herald on Thursday, said he “wished” his property value had only dropped 15 per cent.

Many said the true market value of their properties was zero because no one would buy them due to the per- and poly-fluoroalkyl chemicals [PFAS] spread from Williamtown RAAF Base.

“There’s no doubt that 15 per cent is extremely conservative,” Mr Payne said. 

“It’s so frustrating and very disappointing that here we have proof in these letters that the land has been devalued because of the pollution, but the authorities won’t do anything to help us. It’s hard to even know what to say about it.”

News of the official land value reduction brings properties in Fullerton Cove and Salt Ash, in line with the other 500 households in the original red zone boundaries that were reduced by 15 per cent in November 2016.

Fullerton Cove resident Sue Walker said residents were stuck, unable to get out.

“We bought there 15 years ago and we thought it was paradise,” she said. “It was until Defence destroyed it. Now we can’t get out of there quick enough, but we’re all trapped.”

It’s the latest blow in a horror week for residents.

Earlier this week the Turnbull Government announced it would not be buying owners out of contaminated properties and a controversial sand mine- opposed by residents - was approved by the NSW Independent Planning Commission. 

It also emerged this week that the Federal Government's expert health panel found there was no evidence the chemicals at the centre of the scandal had a “large impact” on human health. 

This was despite the panel finding “consistent” evidence tying the contaminants to a string of adverse health effects, including disruption of the immune system. 

Michelle and Paul McMahon, who bought two acres in Fullerton Cove 14 years ago as part of their retirement plan, fear everything they worked for has been taken away.

“All the time we were thinking the place would go up in value as an investment for when we want to retire,” Mrs McMahon said. “Now we can’t do that...the whole thing is disgraceful.” 

Another Fullerton Cove resident, who asked not to be named, said she moved away from the area in January because of the pollution.

It took her five months to find a tenant at half the rent a real estate agent said the property was worth.

“The place looks like a resort and now it’s worth nothing,” she said. “It’s one thing to rent the place at a hugely reduced price, it’s another thing completely to find a buyer.

“We were lucky that my husband got a job offer and we got the hell out of there for our health, not everyone can do that. It’s a disgrace.”

She said if Defence had been “upfront” about the contamination she never would have bought in 2010. 

“Now the NSW government thinks it’s a good idea to just hand out a letter to residents and pretend we’ve only lost 15 per cent off our property prices, it’s just wicked,” she said.

“We looked at our place originally and thought it was a gold mine. We had the closest land to the coast and the CBD that hadn’t been developed. Before all this exploded we’d already doubled our money, now we’re left with nothing.”

The NSW Valuer General’s review in 2016 of “benchmark valuations” and sales within the original red zone confirmed that values had reduced. 

The report found that there had been nine sales in the original area since it was announced in September 2015, compared to an annual average of 16 sales. 

There has only been one sale in the extended red zone area since it was announced in November.