What are they?

Endocrine disruptors are chemical substances that can interfere with the normal functioning of the endocrine system and, when this interference causes adverse effects, may affect people’s health, their offspring and the environment.

The endocrine system regulates essential functions such as growth and development, metabolism, reproduction, the immune response and other physiological processes. Substances with endocrine activity are not necessarily endocrine disruptors: for a substance to be considered to have endocrine-disrupting properties, there must be endocrine activity, an adverse effect and a biologically plausible relationship between the two.

Effects may occur immediately or appear after a latency period. Developmental periods, particularly pregnancy, childhood and other stages of development, may constitute periods of particular susceptibility.

Endocrine disruptors may be of natural or synthetic origin and may be found in raw materials, products and mixtures used in different work activities, as well as being generated as by-products or waste.

Among the possible effects of endocrine disruptors on human health that official sources associate with endocrine disruption are:

1. Exposed women: Breast cancer, endometriosis, embryonic and fetal death, malformations in offspring.
2. Exposed men: Testicular cancer, prostate cancer, reduced sperm count, reduced sperm quality, decreased testosterone levels, changes in thyroid hormone concentrations.
3. Daughters of exposed people: Precocious puberty, vaginal cancer, increased incidence of cancers, deformities of reproductive organs, problems in the development of the central nervous system, low birth weight, hyperactivity, learning problems, reduced intelligence quotient and reading comprehension.
4. Sons of exposed people: Cryptorchidism or undescended testes, hypospadias, reduced sperm count, decreased testosterone levels, problems in the development of the central nervous system, low birth weight, hyperactivity, learning problems, reduced intelligence quotient and reading comprehension.

Scientific evidence also indicates that effects may depend on the timing of exposure, the route and duration of exposure and the characteristics of the substance. In some cases, effects may appear at later stages of life or affect offspring.

What can be done?

Occupational exposure to endocrine disruptors must be included in the assessment of risks arising from chemical agents present in the workplace.

Prevention should primarily aim to avoid exposure and, whenever possible, to replace the substance or process with a less hazardous alternative. When substitution is not technically possible, appropriate prevention and protection measures should be applied to eliminate or reduce the risk to a minimum, following the hierarchy of preventive measures established in the regulations on chemical agents.

Preventive measures may include:

1. Elimination or substitution of the endocrine disruptor whenever possible.
2. Modification of the process or working conditions to prevent or minimise the release of the agent.
3. Application of technical and collective protection measures, such as closed systems, local exhaust ventilation or adequate general ventilation.
4. Minimisation of the quantities used and of the number of workers exposed.
5. Reduction of the duration and intensity of exposure.
6. Application of organisational and hygiene measures.
7. Use of personal protective equipment when exposure cannot be prevented by other means.
8. Health surveillance where appropriate according to the risk assessment and applicable legislation.

Occupational exposure limit values must be used taking into account the specific characteristics of each substance. In its Occupational Exposure Limits, the INSST uses the note ae (endocrine disruptor) for certain substances and warns that the limit values assigned to these agents have not been established specifically to prevent possible endocrine-disrupting effects. Therefore, compliance with an OEL should not automatically be interpreted as the absence of a risk from endocrine disruption.

Pregnancy and breastfeeding

The risk assessment must take into account pregnancy, recent childbirth and breastfeeding where working conditions may adversely affect the health of the worker, the fetus or the child during breastfeeding.

If the assessment identifies a risk, the company must take the necessary measures to prevent exposure by adapting the working conditions or working time. If adaptation is not possible or does not eliminate the risk, a different position or function compatible with the worker’s situation must be assigned.

Where a change of position is not technically or objectively possible, the employment contract may be suspended due to risk during pregnancy or breastfeeding where the legally established conditions are met.

Protection during pregnancy and breastfeeding must be based on an individual assessment of the exposure conditions and not solely on the existence or absence of an occupational exposure limit value.

Guidelines and reference publications

1. Technical Guide for the Assessment and Prevention of Risks Related to Chemical Agents Present in the Workplace. INSST, 2022.
2. Identification of endocrine disruptors in the workplace. INSST, 2022.
3. Endocrine disruptors. Identify, assess and control. INSST, 2022.
4. Substances with endocrine activity. EFSA.
5. Endocrine disruptors. Spanish Ministry for the Ecological Transition and the Demographic Challenge.
6. Endocrine Disruptors. ECHA.
7. Endocrine disruptors / information on chemicals that disrupt the endocrine system. WHO.
8. Guide on risks from exposure to endocrine disruptors from a gender perspective. CCOO de Catalunya, 2023.

Classification

The Commission Delegated Regulation (EU) 2023/707 introduced new hazard classes into the CLP Regulation for endocrine disruption, both for human health and for the environment.

Endocrine disruption for human health

Substances are classified into two categories:

Category 1. Known or presumed endocrine disruptors for human health

Classification is based on evidence from human data, animal data or methods with equivalent predictive capacity. There must be evidence of:

1. endocrine activity;
2. an adverse effect in an intact organism, its offspring or future generations;
3. a biologically plausible relationship between the endocrine activity and the adverse effect.

Category 2. Suspected endocrine disruptors for human health

This applies where there is evidence of endocrine activity and an adverse effect, together with a biologically plausible relationship between the two, but the evidence is not sufficiently conclusive to classify the substance in Category 1.

Classification is carried out through an assessment of the overall evidence, taking into account the weight of evidence and scientific judgement.

Endocrine disruption for the environment

The CLP Regulation also establishes two categories for endocrine disruption for the environment:

1. Category 1: known or presumed endocrine disruptors for the environment.
2. Category 2: suspected endocrine disruptors for the environment.

In this case, the assessment considers adverse effects on organisms, populations or subpopulations and the biologically plausible relationship with endocrine activity.

Mixtures

A mixture is classified as an endocrine disruptor for human health or for the environment when it contains at least one component classified as Category 1 or Category 2 and the generic concentration limits established in the CLP Regulation are reached.

For endocrine disruption for human health:

The same generic limits apply to endocrine disruption for the environment.

If a mixture contains a Category 2 endocrine disruptor at a concentration equal to or above 0.1%, the obligation relating to the safety data sheet established by the CLP Regulation must be taken into account.

Transitional application

For substances, the new classification and labelling criteria apply at the latest from 1 May 2025, with a transitional period for substances placed on the market before that date until 1 November 2026.

For mixtures, the new criteria apply at the latest from 1 May 2026, with a transitional period for mixtures placed on the market before that date until 1 May 2028.

Identification of substances

There is no single universal and exhaustive list of all endocrine disruptors, a distinction should be made between:

1. substances that have already been recognised and regulated because of their endocrine-disrupting properties;
2. substances included in the REACH Candidate List of substances of very high concern because of endocrine-disrupting properties;
3. substances being assessed by ECHA for possible endocrine-disrupting properties;
4. substances for which there are indications or scientific information, but whose regulatory assessment has not yet been completed.

The ECHA Endocrine Disruptor Assessment List contains substances for which assessment of these properties is ongoing or has been completed. Inclusion on this list does not in itself mean that the substance has been legally recognised as an endocrine disruptor or that a regulatory measure has been adopted.

The REACH Candidate List has a regulatory status. When a substance is included on it because of endocrine-disrupting properties, the obligations arising from REACH must be applied.

Legislation

1. Law 31/1995 of 8 November, on Occupational Risk Prevention, particularly Articles 15, 16, 25 and 26.
2. Royal Decree 374/2001 of 6 April, on the protection of the health and safety of workers against risks related to chemical agents at work.
3. Royal Decree 39/1997 of 17 January, approving the Regulation on Prevention Services, including Annexes VII and VIII concerning pregnancy and breastfeeding.
4. Regulation (EC) No 1907/2006 (REACH), in particular the procedure for identifying substances of very high concern.
5. Regulation (EC) No 1272/2008 (CLP), as currently applicable.
6. Commission Delegated Regulation (EU) 2023/707, introducing hazard classes relating to endocrine disruption for human health and for the environment.
7. Chemicals Strategy for Sustainability – Towards a Toxic-Free Environment, COM(2020) 667 final, as a European Union policy document.

Official references

1. National Institute for Occupational Safety and Health (INSST): endocrine disruptors and occupational risk prevention.
2. INSST: Occupational Exposure Limits for Chemical Agents in Spain, 2026 edition.
3. European Chemicals Agency (ECHA): Endocrine Disruptor Assessment List.
4. ECHA: REACH Candidate List of substances of very high concern.
5. European Food Safety Authority (EFSA): substances with endocrine activity.
6. European Commission: Chemicals Strategy for Sustainability.
7. World Health Organization (WHO): information on chemicals that disrupt the endocrine system.

Last reviewed: August 2026.