May 12, 2026

PFAS – what does the science say?

Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) are a large class of chemicals, sometimes dubbed ‘forever chemicals’. They are used widely in consumer products such as non-stick pans, rinse-aid, cosmetics and stain-resistant clothing/carpets.  They all have a strong carbon-fluorine bond which typically means they break down slowly in the environment.

Studies have found PFAS in human blood and urine, and some have been linked to numerous health effects such as raised cholesterol, reduced antibody response to vaccines, liver enzyme changes and some testicular cancers – as well as bioaccumulation in other species and potential ecotoxicological effects.

Two chemicals in the class, PFOS and PFOA, are now banned in the UK and some are calling for the entire class to follow suit.  But this is a huge group of chemicals with varying properties and we’re typically exposed to them at low levels.  What does the science say about PFAS? What do we definitely know about the impacts of PFAS and what is more speculative? Where are the gaps in the scientific knowledge? How concerned we should be and how should we legislate, especially in the face of uncertainty and incomplete data?

This extended briefing addressed questions such as:

• How are we exposed to PFAS and how are they affecting us?
• What are their toxicological effects and is there a ‘safe’ level?
• How should they be regulated?
• Do they really last ‘forever’?
• Are they necessary – and if not is there something we should replace them with?
• How are they affecting wildlife and ecosystems?
• Is a national clean-up needed and is it even possible at scale?

Journalists came to this background briefing to hear from six experts and put your questions to them.  

Speakers included:

Dr Tony Fletcher, Honorary Associate Professor in Environmental Epidemiology at the London School of Hygiene & Tropical Medicine – epidemiology, human health outcomes

Prof Leon Barron, Professor of Analytical & Environmental Sciences at Imperial College London – measurement & exposure, biological pathways

Dr Luigi Margiotta-Casaluci, Senior Lecturer in Toxicology at King’s College London – toxicology, evidence around health impacts

Prof Stuart Harrad, Emeritus Professor of Environmental Chemistry at the University of Birmingham – exposure science, environmental contamination, analytical chemistry

Dr Elma Lahive, Senior Ecotoxicologist at the UK Centre for Ecology & Hydrology – ecosystem & wildlife effects, ecotoxicology

Prof Madeleine Bussemaker, Professor in Chemical Engineering at the University of Surrey – engineering / remediation, removal and treatment