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OHSAS 18001: What It Was, and Why It’s Now ISO 45001 

OHSAS 18001 was the widely used standard for occupational health and safety management systems, before it was withdrawn. Organizations transitioned to ISO 45001, which replaced it. If you still see OHSAS 18001 referenced, it’s a legacy certification; the current standard for the same job is ISO 45001.

Why does OHSAS 18001 still matter? 

OHSAS 18001 still matters mainly as context: it was the standard many organizations built their health and safety management systems around before ISO 45001 existed. Knowing what it covered explains why current systems look the way they do and what changed in the transition. If you still see it referenced on old certificates or in documents, it points to a legacy system that should now be aligned with ISO 45001.

What did OHSAS 18001 do? 

It set the framework for managing workplace health and safety:
  • A management system for identifying and controlling OH&S risk.
  • Policy, planning, implementation and checking, on a plan-do-check-act cycle.
  • Certification through an accredited third party.
  • Widely adopted before an international ISO standard existed. 

Why was it replaced by ISO 45001

To become a true international standard with a modern structure. ISO 45001 replaced OHSAS 18001, adding stronger leadership and worker-participation requirements and the shared high-level structure that lets it integrate with ISO 9001 and 14001. Certificates were transitioned over a set period. Any live safety management system certifies to ISO 45001 now, not OHSAS 18001.

OHSAS 18001 vs ISO 45001 at a glance

The legacy standard versus its replacement. 
 
AspectOHSAS 18001ISO 45001
StatusWithdrawnCurrent
ScopeOH&S managementOH&S management
StructureStandaloneHigh-level structure
Use todayLegacy references onlyThe standard to certify to

Related Terms

Further Reading

Still on a legacy OH&S standard?
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