A map of expertise, not a division of responsibility
Article 34 of Royal Decree 39/1997 connects higher-level functions with these disciplines. The basic, intermediate and higher levels describe capabilities and functions; they are not three additional disciplines.
The company retains its duty of protection. Having specialists supports well-founded decisions, but does not transfer all prevention to the prevention service. Purchasing, maintenance, operations and management must implement measures within their own areas.
Occupational safety
This focuses on conditions that may cause accidents: access to moving parts, falls, traffic, electricity, fires or energy releases. It analyses equipment, installations, tasks and the organisation of operations.
It may require inspections, accident analysis, equipment assessment and selection of safeguards. A risk is not resolved simply because a written procedure exists: design, resources and execution must be checked to establish that safe work is possible.
Occupational hygiene
Occupational hygiene identifies and assesses exposure to chemical, physical and biological agents. It determines when measurements are necessary, how to obtain representative results and which measures reduce exposure.
Its work is not limited to comparing a number with a limit. It includes assessing task duration and variability, routes of exposure, extraction effectiveness and process changes. An isolated sample may not represent every shift or circumstance.
Ergonomics and applied psychosociology
Ergonomics studies the fit between people, tasks and resources: exertion, postures, repetition, mental workload, interfaces and conditions of use. Applied psychosociology analyses organisational factors such as demands, autonomy, support, roles and working time.
In the Spanish classification, they form a combined discipline. This does not mean that the same technique suits every problem: a manual handling assessment does not replace analysis of work organisation.
Occupational medicine and healthcare collaboration
This addresses the relationship between work and health through competent healthcare professionals. Article 37 of the Regulation includes specific surveillance, study of collective results and collaboration with other disciplines to propose improvements.
Individual medical information has specific protection. The company receives the appropriate preventive conclusions, not a complete medical history. A recommendation for adaptation must connect with actual tasks and exposures while respecting that confidentiality.
How to decide who should be involved
Start from the problem: what is happening, during which task, with what exposure and affecting whom. An in-house service must cover at least two disciplines and contract for those it does not cover; entities acting as external prevention services must have all four, under the Regulation.
These organisational requirements do not replace checking competence for a specific assessment. A complex project may require joint work, specialist measurements or additional technical support.
Hypothetical example: a new welding workstation
Safety reviews fires, projected material and equipment. Hygiene analyses fumes and extraction. Ergonomics examines postures and reach to components, while psychosociology considers pace and organisation. Occupational medicine uses risk information for the appropriate health surveillance.
The outcome should be a coherent set of decisions. A protective screen that prevents good posture or extraction that makes the operation difficult requires joint review, rather than four disconnected reports.
