Every Swiss company with employees must protect their safety and health. As soon as the work involves particular hazards, it must also call in specialists and be able to prove it. That is what the MSST directive (EKAS/CFST no. 6508, called the ASA directive in German) is about. This first article in the series explains what it is and who it applies to.
The directive in short
MSST stands for médecins du travail et autres spécialistes de la sécurité au travail: occupational physicians and other occupational safety specialists. It puts article 11a of the Accident Prevention Ordinance (OPA/VUV, SR 832.30) into practice: the employer must call in specialists when the health and safety of workers require it.
- The duty depends on the risk, the number of people employed and the specialist knowledge needed (art. 11a para. 2).
- Calling in specialists does not relieve the employer of responsibility (art. 11a para. 3).
- Following the EKAS directives gives a presumption of compliance. Another route is allowed if the employer proves that safety and health are guaranteed (art. 11b).
Specialists are occupational physicians, occupational hygienists, safety engineers and safety specialists with the required qualification (art. 11d).
Who is concerned?
Two questions decide: do you have particular hazards as listed in annex 1, and how many people do you employ? Headcount is taken across the whole company, temporary staff included.
| Situation | What the directive requires |
|---|---|
| Particular hazards, 10 people or more | Proof of the specialists called in or the measures taken, and proof of the safety organisation (section 3.1) |
| Particular hazards, fewer than 10 people | Proof by simple means: photos, maintenance contracts, completed checklists (section 3.2) |
| No particular hazards, 50 people or more | Calling in specialists is optional, but the safety organisation must be proven (section 3.3) |
| No particular hazards, fewer than 50 people | The general duties of articles 3 to 10 of the ordinance (section 3.4) |
The particular hazards
Annex 1 groups them by type of work: mechanical, falls from 2 m, electrical, harmful chemical or biological substances, fire and explosion, thermal, physical (noise, vibration, radiation), special work environments (confined spaces, night or shift work, violence) and the musculoskeletal system.
The annex itself says it is not a hazard identification tool. It tells you whether you are concerned. To identify hazards, Suva offers its own methods, such as the hazard portfolio and its checklists.
How ENSURE fits
Your "particular hazards: yes or no" answer should rest on a written, dated assessment. In ENSURE:
- Add the annex 1 hazard types as categories in your risk register. Each risk has its category, score, owner and review date.
- Break risky tasks down in a job hazard analysis (JHA).
- Load your safety data sheets into chemicals: the hazard statements of each product help you spot the chemical hazards of annex 1.
You get a list you can filter by category that shows, in one click, why you are concerned or not.
Sources: MSST directive, CFST no. 6508, French (as of 23 October 2025); OPA/VUV (SR 832.30), art. 3 to 11d.
Your particular hazards, documented
See in 30 minutes how to keep your risk register with the annex 1 categories.