Firefighters exposed to contaminated drinking water at a Victorian airport have elevated levels of toxic chemicals in their blood, tests show.
Authorities are still trying to work out how PFAS chemicals got into drinking water at Avalon Airport's fire station and air traffic control tower.
Airservices Australia, which operates fire and air traffic services at the site, last month revealed PFAS readings of 3080 and 5800 parts per trillion had been detected.
The safe drinking water standard is 70 parts per trillion.
The United Firefighters Union says blood tests ordered for 30 firefighters and two air-traffic controllers are now revealing the impacts for those workers.
"Every one I've seen so far is higher, considerably higher, than their previous tests and much higher also than the normal community background levels," says Wes Garrett, the union's aviation branch secretary.
"We're not surprised. It confirms they have been drinking contaminated water. The question remains for how long. That's still unclear."
Man-made PFAS chemicals are often referred to as forever chemicals because they are very slow to break down and accumulate in human bodies.
They have been associated with a range of serious health issues and some of the worst types were in firefighting foams that are now banned but have left lasting contamination issues at airports and defence sites.
Mr Garrett says many affected firefighters were previously tested for PFAS, because it was a known risk for those in the profession.
"Some of them are up to 15 times higher now (than they were a year ago)"
One Avalon firefighter, who asked not to be named, has given AAP his blood test results.
Since his previous test last year, one particular PFAS chemical is up by more than 700 per cent.
"We're no scientists, we're just firies but the trends have all shown that anyone tested in 2021 was quite normal and now, in 2022, they've gone through the roof, they've really spiked," he said.
The only known way to reduce PFAS levels at a relatively quick rate is for people to make repeated blood or plasma donations.
Of the relatively few well-studied PFAS, most are considered moderately to highly toxic.
Many governments worldwide now warn certain exposure levels may lead to increased cancer and other health risks from substances heavily used in consumer and industrial products since the 1940s.
The Australian government, in its new draft PFAS management plan, urges a precautionary approach focused on limiting exposure.
Firefighters are now back at work at Avalon Airport's fire station, after the facility was deep cleaned, and taps and sinks replaced along with water pipes to exterior of the building.
"The drinking water taps are now PFAS-free, with clean, tank-supplied water. Regular monitoring is ongoing," said Airservices Australia, which says it has never used PFAS firefighting foam at the leased airport site.
It says surface swab testing at the station has shown there is no risk to human health.
Site owner Avalon Airport has confirmed PFAS foams were historically used at the site.
AAP has asked for an update on its investigation into the cause of the drinking water contamination.
