Authorities are scrambling to work out how toxic PFAS chemicals got into drinking water at a major Victorian airport.
About 30 firefighters and two air-traffic controllers who work at Avalon Airport are being tested after the long-lived contaminants were detected at levels far beyond safe drinking limits.
The United Firefighters Union says anxiety levels are high, with no indication yet how long workers may have been drinking, washing and working in contaminated water.
Water supplies to the terminal and other public buildings are safe, and the airport remains open.
Man-made PFAS chemicals have been associated with a range of serious health issues. They are often referred to as forever chemicals because they are very slow to break down and accumulate in human bodies.
Some of the most harmful types were in fire fighting foams that Australia has now phased out.
But their long-term use has left a legacy of contamination at defence bases and airports across the country, including Avalon.
One affected firefighter, who spoke to AAP on condition of anonymity, says the revelation is incredibly concerning.
Firefighters basically live at the station for their 18-hour shifts, eating there, showering there, washing clothes and equipment there.
He said the early advice was that PFAS levels were three to four times the safe limit.
"When we finally got the accurate information, we were made aware it was 44 times the safe limit for the fire station and it was 72 for the tower.
"Everything in the station has touched this water."
He says workers were told by a university expert who specialises in PFAS that they should essentially discard everything.
Airservices Australia operates the airport's firefighting and air traffic services and told AAP readings of 3080 and 5800 parts per trillion were detected.
The safe drinking water standard is 70 parts per trillion.
To put the readings into perspective, a recent analysis of tap water samples from 44 places in 31 US states, the highest reading was 185.9 parts per trillion.
Airservices Australia says it only leases part of the airport precinct and it has never used fire fighting foam containing PFAS at Avalon.
"The source of the PFAS is unknown at this stage," it said on Monday.
"Fire Rescue Victoria will service the airport during the temporary closure. Airport users will make their own determination on operating at the airport."
The union has told AAP the water is clean coming onto the site.
It says the supply line then splits. The pipe supplying the terminal is clean but another servicing the fire station and control tower is not.
Avalon Airport says PFAS foams were historically used at the site, and it is working to identify the source of the contamination.
"Our priority will be on removing the affected infrastructure and installing new and flushed infrastructure.
"We are working closely with the relevant environmental and health regulators, along with the best independent advisers to identify what measures are required and what appropriate steps need to be taken."
Affected staff have been offered health support, including free blood tests.
