Determining the true extent of "forever chemicals" being used in consumer products is like finding a needle in a haystack, an expert warns.
A parliamentary inquiry into the use of per and polyfluoroalkyl substances, known as PFAS, gets under way on Wednesday as calls grow for more transparency from the companies that use them.
Among those fronting the inquiry is University of New South Wales professor Denis O'Carroll, who says the level of PFAS use might be impossible to gauge.
"We certainly have quantified a few PFAS in these (industrial) products, however, identifying others is akin to finding a needle in a haystack," he said in his submission to the inquiry.
"There are thousands of products on, or previously on the market, that contain PFAS."
Thousands of PFAS chemicals have been created, with uses ranging from firefighting foam to non-stick cookware.
While studies into their use continue, concerns have been raised about potential health risks from exposure to PFAS chemicals, such as cancer.
There is limited evidence of human disease or other clinically significant harm resulting from PFAS exposure.
Professor O'Carroll is helping develop PFAS treatment technology, and said it was concerning manufacturers didn't share what forever chemicals were used in products.
"It is recommended that industry be compelled to provide much more information related to the range and mass of PFAS that have been historically used to help better direct health and ecosystem investigations."
The Senate inquiry will hear from bodies such as the CSIRO, government departments and experts on PFAS remediation and the human health impact of the synthetic chemicals.
It comes after national drinking water guidelines were tightened for potential PFAS chemicals.
Draft benchmarks released in October by the National Health and Medical Research Council were met with criticism that the threshold was 50 times higher than new limits in the US.
Prof O'Carroll said the council needed to consider a wider range of guidelines for PFAS and drinking water, which would bring Australia into line with Europe and Canada.
"At the moment, many of the public are afraid to consume drinking water, even though PFAS would be below all international drinking water standards," he said.
"Governmental agencies need to develop a communication plan of openness and transparency to ensure public confidence."