What are they?

An occupational disease is an illness contracted as a consequence of work which, under Social Security legislation, is included in the official list of occupational diseases and is associated with the agents, substances, activities or exposures specified in that list.

The legal concept is currently established in Article 157 of the consolidated text of the General Social Security Law, approved by Royal Legislative Decree 8/2015, and is further developed by Royal Decree 1299/2006, which establishes the list of occupational diseases and the criteria for their notification and registration.

“An occupational disease shall be understood as one contracted as a consequence of work carried out for an employer in the activities specified in the list approved by the provisions implementing and developing this Law, and caused by the action of the elements or substances indicated in that list for each occupational disease.”

The list of occupational diseases establishes a relationship between:

1. the agents or substances capable of causing the disease;
2. the diseases or health disorders associated with those agents;
3. and the occupational activities in which exposure may occur.

Therefore, when a worker develops a disease included in the list and there is a correspondence with the agent and occupational activity specified in it, the disease may be recognised as an occupational disease.

The list of occupational diseases is contained in Annex I to Royal Decree 1299/2006. Annex II contains a complementary list of diseases whose occupational origin is suspected and whose inclusion in the official list could be considered in the future.

It is important to bear in mind that not all work-related diseases are included in the list of occupational diseases. A relationship between work and harm to health may exist even when the disease does not appear in the list.

In certain cases, diseases not included in the list may be considered an occupational accident if it is demonstrated that they were contracted as a result of carrying out the work and that the work was their exclusive cause, in accordance with Article 156.2.e of the General Social Security Law.

The importance of prevention

The occurrence of an occupational disease is an indication that there may be a workplace exposure that needs to be investigated and controlled.

The identification of an occupational disease should contribute to:

1. investigating the working conditions and exposures that may have caused it;
2. reviewing the risk assessment where necessary;
3. adopting or improving preventive and protective measures;
4. preventing further exposures and new cases;
5. and carrying out appropriate health monitoring of workers.

Investigating cases of occupational disease is a fundamental tool for identifying the working conditions that have contributed to their occurrence and for improving prevention.

The National Institute for Occupational Safety and Health (INSST) has a specific procedure for investigating these cases, as well as guidelines updated in 2025.

What should be done?

Workers and their representatives can contribute to the prevention of occupational diseases by:

1. knowing the hazardous agents and substances present in the workplace and the diseases they may cause;
2. checking that health risks arising from occupational exposures have been identified and assessed;
3. requesting information on the applicable preventive and protective measures;
4. reporting any suspected work-related harm to health to the occupational health and safety services and the relevant healthcare services;
5. promoting the investigation of occupational disease cases or suspected cases of occupational origin;
6. ensuring that measures are adopted to eliminate or reduce hazardous exposures;
7. and ensuring appropriate health surveillance adapted to the existing risks and respectful of workers' rights.

The notification of occupational diseases included in the official list is carried out through CEPROSS (Communication of Occupational Diseases in the Social Security System). The occupational disease report is prepared and transmitted in accordance with the applicable legislation. Order TAS/1/2007 – occupational disease report and transmission of information (BOE)

Occupational diseases and work-related diseases

A distinction should be made between:

Occupational disease: a disease that meets the requirements established in Article 157 of the General Social Security Law and is included in the list established by Royal Decree 1299/2006, under the conditions set out therein. General Social Security Law – Article 157 (BOE)

Work-related disease: a relationship may exist between working conditions and harm to health even though the disease does not appear in the list of occupational diseases. Its recognition as an occupational contingency will depend on the circumstances and on the evidence required by law.

This distinction is important because the list of occupational diseases has a legal status and is not an exhaustive list of all forms of harm to health that may be related to work.

Classification

Annex I to Royal Decree 1299/2006 classifies occupational diseases into six groups, according to the agents that cause them:

1. Group 1: occupational diseases caused by chemical agents.
2. Group 2: occupational diseases caused by physical agents.
3. Group 3: occupational diseases caused by biological agents.
4. Group 4: occupational diseases caused by inhalation of substances and agents not included in other sections.
5. Group 5: occupational skin diseases caused by substances and agents not included in any of the other sections.
6. Group 6: occupational diseases caused by carcinogenic agents.

Each group is subdivided into agents, sub-agents and activities, using a coding system that makes it possible to identify and register occupational diseases notified through CEPROSS.

The Risctox database contains the substances and agents included in Annex I to Royal Decree 1299/2006 that may be associated with occupational diseases, together with the relevant information from the official list.

Annex II contains a complementary list of diseases whose occupational origin is suspected and whose inclusion in the official list could be considered in the future. Royal Decree 1299/2006 – Annexes I and II, consolidated text (BOE)

Gender perspective

The identification and prevention of occupational diseases should take into account possible differences related to sex and gender.

Workers may be exposed differently to occupational risks due, among other factors, to occupational segregation, the distribution of tasks, employment conditions, the work or personal protective equipment used, and the characteristics of particular jobs.

In addition, for certain agents and diseases, there may be biological differences related to sex that should be taken into account where there is sufficient scientific evidence.

Therefore, risk assessment and health surveillance should avoid using a single worker profile as a reference and should consider relevant differences where these may affect exposure, susceptibility or health consequences.

Legislation

1. Royal Legislative Decree 8/2015 of 30 October, approving the consolidated text of the General Social Security Law, particularly Articles 156 and 157, concerning occupational accidents and occupational diseases.
2. Royal Decree 1299/2006 of 10 November, approving the list of occupational diseases in the Social Security system and establishing criteria for their notification and registration.
3. Royal Decree 1150/2015 of 18 December, amending Royal Decree 1299/2006.
4. Royal Decree 257/2018 of 4 May, amending Royal Decree 1299/2006.
5. Order TAS/1/2007 of 2 January, establishing the occupational disease report form, setting out rules for its preparation and transmission, and creating the corresponding personal data file.

References

Spanish institutional sources

1. National Institute for Occupational Safety and Health (INSST).Guidelines for the investigation of occupational disease cases. 2025. I
2. National Institute for Occupational Safety and Health (INSST).Procedure for the investigation of occupational disease cases. 2022.
3. National Institute for Occupational Safety and Health (INSST).Guidelines for clinical decision-making in occupational diseases (DDC).

International sources

1. International Labour Organization (ILO). ILO List of Occupational Diseases, revised in 2010.
2. International Labour Organization (ILO). Diagnostic and exposure criteria for occupational diseases – Guidance notes for diagnosis and prevention of the diseases in the ILO List of Occupational Diseases (revised 2010). 2022.

Last interface update: August 2026.