ISO 45001 was published in March 2018 and replaced OHSAS 18001, which has since been withdrawn. Organisations that built their safety systems on OHSAS 18001 will recognise most of the content, but the emphasis has moved.
The context of the organisation
ISO 45001 asks you to look at the internal and external issues that affect safety, and at the needs of interested parties such as workers, contractors, regulators and clients. OHSAS 18001 had no equivalent clause.
Leadership
Top management has to take an active role. Under OHSAS 18001 much of the work could be delegated to a management representative. ISO 45001 expects leaders to be accountable for the system and to show it.
Worker consultation and participation
The new standard requires that non-managerial workers are consulted and take part in decisions on hazards, controls, training and incident investigation.
Risks and opportunities
Planning covers risks to the management system itself, and opportunities to improve, as well as hazards to people.
A shared structure
ISO 45001 follows the same high-level structure as ISO 9001 and ISO 14001, which makes it easier to run an integrated system if you hold more than one standard.
If you are moving from OHSAS 18001, a gap analysis is the quickest way to see what needs to change.