PFAS, cancer classification and Australian drinking water

The IARC classification — what it actually means

In November 2023, a working group of 30 scientists from 11 countries convened by the International Agency for Research on Cancer (IARC) — the WHO’s cancer research agency — published its formal evaluation of PFOA and PFOS as IARC Monographs Volume 135, also published in The Lancet Oncology (doi:10.1016/S1470-2045(23)00622-8). The conclusions:

• PFOA (perfluorooctanoic acid): Group 1 — carcinogenic to humans. The highest IARC category, shared with tobacco smoke, asbestos and ionising radiation. Based on sufficient evidence for cancer in experimental animals, strong mechanistic evidence in humans (epigenetic alterations, immunosuppression), and limited but positive human evidence for renal cell carcinoma and testicular cancer.
• PFOS (perfluorooctane sulfonic acid): Group 2B — possibly carcinogenic to humans. Strong mechanistic evidence; limited animal and inadequate human evidence at time of evaluation.

IARC Group 1 identifies a cancer hazard — evidence an agent can cause cancer. It does not quantify risk at a specific exposure level. Tobacco and processed meat are both Group 1; their actual risk levels are not equivalent. The practical question for Australian drinking water consumers is not "is PFOA a carcinogen?" but "am I exposed at levels that meaningfully increase my cancer risk?"

Australia’s regulatory response — the June 2025 ADWG update

The NHMRC reviewed its Australian Drinking Water Guidelines (ADWG) for PFAS from 2023 to 2025, directly responding to the IARC classification and updated international evidence. In June 2025 new, substantially lower health-based guideline values were published:

The PFOS limit tightened nearly ninefold. The NHMRC confirmed that the vast majority of Australian public water supplies already meet the new values. These are conservative limits based on lifetime exposure — a reading above the guideline is managed by water authorities, not an immediate emergency.

Where PFAS has been found in Australian drinking water

Elevated PFAS in Australian tap water is concentrated near contamination point sources. The NHMRC and state health authorities identify the clearest pattern as proximity to:

• Defence bases: RAAF Williamtown (NSW), RAAF Oakey (QLD), RAAF Tindal (NT) and others where PFOS-containing firefighting foam (AFFF) was used for decades. The ANU PFAS Health Study (2021) confirmed elevated PFOS and PFHxS blood levels in communities near these sites.
• Civil airports: Perth Airport and Jandakot Airport are under ongoing PFAS investigation. Airservices Australia used PFOS-containing AFFF at 56 sites between the 1980s and early 2000s.
• Sydney Blue Mountains: WaterNSW detected PFAS in raw catchment water feeding the Cascade Water Filtration Plant. Sydney Water confirmed treated drinking water met ADWG values throughout, with blending and treatment measures implemented.

The critical distinction: PFAS in raw (untreated) source water is not the same as PFAS in your tap water. ADWG guidelines apply to treated water. Most metropolitan scheme water is well below current guideline values.

The exposure context

The NHMRC estimates drinking water typically contributes approximately 2–3% of total PFAS exposure for Australians in low-contamination areas. Up to 90% of PFAS exposure in Australia comes from food, cookware, waterproof textiles and household products. Drinking water is not the main source — but for communities near contaminated sites, its proportional contribution is significantly higher and filtration has the most meaningful impact.

From 1 July 2025, PFOA, PFOS and PFHxS are prohibited from import, manufacture and export in Australia under the Industrial Chemicals Environmental Management Standard (IChEMS). Historical contamination from decades of use will persist in the environment regardless.

What actually removes PFAS from drinking water

Standard carbon block filters — the core technology in most Australian whole-home and under-sink systems — have partial and inconsistent PFAS effectiveness at residential flow rates. The reliably verified residential technologies are:

• Reverse osmosis (NSF 58 certified): Removes 90–96% of PFAS. The most reliable residential technology. NSF 58 includes specific PFAS removal claims. Verify at nsf.org for the exact product model.
• Certified carbon block with specific PFAS claims: Some high-contact-time systems have been independently tested under NSF 53 or 58 for PFAS. Must be verified against the certification database — not taken on the supplier’s word.

How to check PFAS levels in your supply

Every major Australian water utility now publishes PFAS monitoring data. For scheme water, check your utility’s water quality reporting page: Water Corporation (WA), Sydney Water (NSW), SA Water, SEQ Water (QLD), Melbourne Water (VIC). The Australian Government’s pfas.gov.au portal also summarises contamination sites and investigations by state. For private bore or tank water near a contaminated site, NATA-accredited laboratory PFAS testing costs approximately $200–$400.