Guidance

Perfluoroalkyl and polyfluoroalkyl substances (PFAS): general information

Published 22 September 2026

What are PFAS

Per- and polyfluoroalkyl substances (PFAS) are a group of thousands of man-made chemicals that have been widely used since the 1950s. Although PFAS share certain features, they can have very different chemical structures. This means they behave differently in the environment and in the body.

They are sometimes referred to as “forever chemicals” because they persist in the environment for a very long time. This persistence is due to the strong carbon-fluorine bonds in their chemical structure, which do not break down easily.

PFAS in everyday life

PFAS are used in many industrial sectors and everyday settings because they are resistant to water, oil and stains, and can withstand high temperatures. As a result, PFAS can be found in a wide range of products, such as:

• textiles (such as clothing, carpets and furniture)
• non-stick cookware
• food packaging materials
• personal care products
• cosmetics
• electronics
• paints, waxes and plastics
• lubricants
• pesticides
• vehicles
• medical devices
• fire-fighting foams

Because PFAS are used in many products and industrial processes, they can also be found in food, drinking water, air, dust and soil. For most people, diet and drinking water are thought to be the main ways PFAS can get into the body. Other possible routes include indoor dust and skin contact with PFAS-containing products.

Drinking water in the UK is monitored and regulated to help protect public health and minimise PFAS levels. Further information on PFAS in drinking water can be found on the Drinking Water Inspectorate’s web page about PFAS and Forever Chemicals.

If you work in a job that produces or uses PFAS and PFAS-containing materials, you may be exposed to PFAS at work. If you have concerns about your PFAS exposure at work, you should speak to your employer or contact the Health and Safety Executive, who is responsible for workplace safety.

PFAS in the environment

PFAS have been used for many decades, and because they do not break down easily, they are now widely found in the environment. Efforts are being made to better understand the sources of PFAS in the environment and reduce future releases.

The Environment Agency is responsible for managing PFAS emissions to the environment. You can read more at The Environment Agency’s role with PFAS ‘Forever Chemicals’ Engage Environment Agency.

Possible dangers of PFAS

PFAS do not break down easily, so they can remain in the environment for a long time, and ongoing exposure may lead to a gradual build‑up of certain PFAS in the body. However, this does not mean that PFAS will remain in the body permanently. Different PFAS behave differently once they enter the body: long‑chain PFAS (those with longer carbon chains) can stay for years, while many short‑chain PFAS (with shorter carbon chains) are usually cleared within days to months. Some long‑chain PFAS have been restricted because they can build up in people and animals and may cause harmful effects. These have mostly been replaced with short‑chain PFAS, which the body clears more quickly.

People are often exposed to a mixture of PFAS at the same time. Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonic acid (PFOS) are often detected at the highest levels because they were widely used for many years before being phased out. Other PFAS, such as perfluorohexane sulphonate (PFHxS) and perfluorononanoic acid (PFNA), may also be detected but generally at lower levels, depending on their past uses and how long they remain in the body or the environment.

Because PFAS vary in how they behave and how long they stay in the body, the potential health effects of exposure can also vary. Whether PFAS exposure has an impact on your health will depend on several factors, including:

• how much you were exposed to (the concentration)
• the way you were exposed
• how long you were exposed for (duration)
• the type of PFAS
• the form of the chemical (solid or liquid)
• if you were exposed to any other chemicals
• your underlying health (any existing health conditions).

How exposure to PFAS could affect your health

There is growing concern about the possible health risks of PFAS, but only a small number have been well studied. The PFAS with the most research are PFOA and PFOS, with some additional evidence available for PFHxS.

PFAS are a large group of chemicals, and they do not all behave in the same way or pose the same level of risk. Some are more likely to build up in the body or remain in the environment for long periods, and the evidence on their potential health effects differs across the group.

The evidence on the health impacts from PFAS exposure is inconsistent. However, exposure to PFOA and PFOS has been linked with:  

• increases in cholesterol levels
• decreases in birth weight
• reduced immune response to some vaccines
• changes in liver enzyme levels, which may indicate effects on the liver

It is not clear whether these changes directly lead to specific health problems in individuals, and more research is needed to understand their long‑term significance. Other PFAS may cause similar effects, but the evidence is weaker and further research is needed. The long-term effects of exposure are also not well understood for a large proportion of PFAS, which means there is uncertainty when considering possible health effects across PFAS as a group.

At present, it is difficult to determine whether PFAS, individually or as a group, directly cause specific health conditions in humans.

The UK has already banned or restricted the PFAS of greatest concern (including PFOS, PFOA and PFHxS) by putting the requirements of an international agreement (the Stockholm Convention) into UK law. This agreement commits countries around the world to phase out the production and use of these substances. The UK is also preparing to apply the most recent global controls on another group of PFAS called long‑chain perfluorocarboxylic acids (LC‑PFCAs), which have now been added to the same agreement.

The UK Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) is reviewing the available scientific evidence to support the assessment of potential health risks from both current and past exposure to PFAS. This work will be published on the COT website once it is available. For more information on this work, see PFAS - Committee on Toxicity.

PFAS and cancer

Some studies have suggested possible links between exposure to certain PFAS, particularly PFOA and PFOS, and cancers such as kidney and testicular cancer. The likelihood of any health effect will depend on factors such as the amount of PFAS a person is exposed to, how long they are exposed for and the specific PFAS involved.

The International Agency for Research on Cancer (IARC), part of the World Health Organization, has classified PFOA as carcinogenic to humans and PFOS as possibly carcinogenic. However, the overall evidence remains mixed, and expert organisations do not all reach the same conclusions.

PFAS and human biomonitoring

Human biomonitoring is a way of measuring chemicals in the body by testing samples such as blood or urine.

Many people in the UK are likely to have measurable levels of PFAS in the blood. For substances like PFAS that are widespread in the environment, test results reflect exposure from many different sources, including food, drinking water, air and everyday products. This means that a test result cannot tell you where the exposure came from.

For these reasons, PFAS biomonitoring is not currently recommended for individuals through the NHS or private blood tests. At this time, such tests are unlikely to provide clear or helpful information for individuals and can sometimes create unnecessary worry. PFAS blood testing also cannot be used to predict future health problems or determine the cause of any existing ill-health, and there is no evidence that reducing PFAS in the body on an individual basis will improve health outcomes.

The UK Health Security Agency (UKHSA) is developing capabilities to assess human exposure to PFAS and has access to a small number of population samples of blood and urine through the Health Survey for England. By analysing these samples, UKHSA will be able to assess and understand background exposure to PFAS across the general population in England. This type of population-level monitoring helps inform public health advice and chemical regulation but does not provide information that is useful for managing an individual’s health.

PFAS and higher-risk groups

Pregnant people

Some studies have found that some PFAS can cross the placenta during pregnancy, which means that the developing foetus may be exposed. Some research has suggested that PFAS exposure in the mother over their lifetime may be linked to small changes in the birth weight of their child.

Some studies have found that breastfeeding can transfer small amounts of PFAS from the mother to the infant. As human milk is the best source of nutrition for most infants, breastfeeding or providing human milk is recommended when possible. Current scientific evidence shows that the benefits of breastfeeding outweigh any potential risks from PFAS in breast milk.

The amount of PFAS an infant may be exposed to through breastfeeding can vary. It depends on:

• the level of PFAS in the mother
• the level of PFAS in breast milk
• the duration of breastfeeding.

There is currently no established PFAS level in breast milk that indicates a health risk for either the infant or the mother.

Children

Infants and young children may be more vulnerable to the potential effects of PFAS because their bodies and organs are still developing. They can be exposed in several ways, including through breast milk, formula made with PFAS contaminated water, or hand to mouth behaviours such as mouthing toys or fabrics.

Some studies have suggested that PFAS exposure may be linked with effects such as reduced immune response to some vaccines, although the evidence is mixed and not all studies report the same findings.  More research is needed to understand the long‑term significance of PFAS exposure in childhood.

Breastfeeding remains the recommended source of nutrition for most infants, and current evidence shows that the benefits of breastfeeding outweigh any potential risks from PFAS in breast milk.

What the Government is doing about PFAS

A cross-government, science-led plan has been published to improve understanding of the impacts of PFAS on public health and the environment, and to coordinate actions to minimise risks, see the PFAS Plan.

The plan sets out the government’s overall approach to PFAS and includes actions to:

• understand sources of and exposure to PFAS
• tackle the ways PFAS enter and move through the environment
• reduce ongoing exposure to PFAS

The plan reflects the government’s commitment to protect public health and the environment.

What UKHSA is doing about PFAS

The UK Health Security Agency (UKHSA) provides independent scientific advice to help protect people from potential health risks linked to PFAS exposure through water, soil and air. UKHSA works with partners across government to strengthen the evidence base on PFAS and to support policy and regulatory decisions.

UKHSA is developing a human biomonitoring programme to understand population exposure to chemicals in our daily lives, including PFAS.

UKHSA has published a review on the health impacts from industrial sources of PFAS. The report is available t The health impacts from industrial sources of PFAS: a rapid review.

UKHSA recognises growing public concern about PFAS and will continue to work with partners to improve knowledge, inform risk assessment and support decision making to protect public health. More information about UKHSA’s wider responsibilities can be found at What we do: UK Health Security Agency.

Additional sources of information

For more information on PFAS in drinking water, see:

• PFAS and Forever Chemicals - Drinking Water Inspectorate

For statements and position papers from the Committee on Toxicity (COT), see:

• Interim Position Paper on Per- and Polyfluoroalkyl Substances Committee on Toxicity
• Statement on the EFSA Opinion on the risks to human health related to the presence of perfluoroalkyl substances (PFASs) in food: Lay Summary Committee on Toxicity

For information on UK‑wide policy and regulatory action on PFAS, see:

• the PFAS plan

For information on PFAS in the environment, including monitoring and regulation, see:

• The Environment Agency’s role with PFAS ‘Forever Chemicals’ Engage Environment Agency

For international guidance on PFAS and global assessments of health and environmental risks, see:

• Assessing the occurrence and human health risk of per- and polyfluoroalkyl substances

Email chemcompendium@ukhsa.gov.uk if you have any questions about this guidance or enquiries@ukhsa.gov.uk if you have any other questions.