Pesticides users’ health study

About the study

The Pesticide Users' Health Study (PUHS) was established in the late 1990's by the Health and Safety Executive (HSE) who also fund it. The aims of the study are to:

  • monitor the long-term health of people potentially exposed to low levels of pesticides on a longer term basis
  • help fill the gaps in knowledge about the extent and nature of pesticide-related ill health

How pesticide users became part of the study

From 1994 to 2003, pesticide users applying for a certificate of competence were asked if HSE could access their information for medical research on pesticide use. For those who agreed, the National Proficiency Tests Council (NPTC) passed their name, contact details and certification information to HSE, and they became members of the study. There are around 65,000 participants from across Great Britain.

How we collected information about participants' pesticide use

From 2004 to 2006, HSE sent a questionnaire to all members of the study asking about:

  • their work with pesticides at the time, and in the past
  • the types of pesticide used and the time spent using them

How we collect information about participants' health

Around 96% of members of the study have been successfully 'flagged' with NHS central registers. This means that HSE will be notified whenever a study member.

  • dies
  • is diagnosed with cancer
  • emigrates from or returns to Great Britain

This information is provided to us each quarter by NHS Digital (for England and Wales) and National Records of Scotland (NRS).

NHS Digital supplies cancer data to HSE. This includes health data such as the date of the event and the cancer type or cause of death, which is regarded as a special category of information. We use this to understand the long-term health of study participants.

We also receive information on hospital admissions for members of the study from NHS Digital. This allows us to investigate long-term ill health, such as neurological and eye diseases.

How we use participants' data

The data collected is used for health research purposes only and is kept strictly confidential. The data will be used to investigate whether there is any evidence of a link between working with pesticides and health. The study findings will be freely available online in HSE research reports or published articles.

The findings are reported in such a way that no individual can be identified.

HSE is the sponsor for this study based in the United Kingdom. We use the information from the participant and their medical records (provided by NHS Digital and NRS) in order to undertake the study and will act as the data controller for the study. This means that HSE is responsible for looking after participants' information and using it properly. HSE will keep identifiable information about participants for 15 years after the study has finished.

The data collected about participants may be provided to researchers running other research studies in HSE or in other organisations. These might be universities or other organisations involved in health research in this country or abroad. Individuals will not be identifiable in any data shared with other approved researchers, and the data will not be combined with other information in a way that could identify an individual participant.

As a government agency we use personally identifiable information to conduct research to improve workers' health. As a publicly funded organisation, we have to ensure that it is in the public interest when we use personally identifiable information from people who have agreed to take part in research. This means that when someone agrees to participate in a research study we will use their data in the ways needed to conduct and analyse the research study.

Participants' rights to access, change or move their information are limited, as we need to manage their information in specific ways in order for the research to be both reliable and accurate. If a participant withdraws from the study, we will keep the information about them that we have already obtained.

To safeguard participants' rights, we will use the minimum personally identifiable information possible.

Health information is sensitive personal data and is regarded as 'special category' data. Sensitive personal data will only be processed for research purposes.

This study does not use automated decision-making or profiling to make decisions about individuals.

If you wish to raise a complaint on how we have handled personal data you can contact our data protection officer by email at [email protected] or you can write to them at the following address:

Data Protection Officer
Health and Safety Executive
1.3 Redgrave Court
Merton Road
Bootle
Liverpool L20 7HS

More information on how HSE processes data is provided in HSE's Privacy Policy Statement.

If you are not satisfied with our response or believe we are processing personal data in a way that is not lawful, you can complain to the Information Commissioner's Office (ICO).

Reports and publications

Reports and publications available:

Withdrawing from the study

You can withdraw from all or part of the study at any time by contacting us using the e-mail address given below.

Contact us

If you have any questions at all about the research, contact us.

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Updated 2025-11-27