The standard is based on OHSAS 18001, conventions and guidelines of the International Labour Organization including ILO OSH 2001, and national standards. It includes elements that are additional to BS OHSAS 18001 which it is replacing over a three-year migration period from 2018 to 2021. As of March 2021, companies and organizations should have migrated to ISO 45001 to retain a valid certification, although ISO has extended the transition period for up to six months (to 11 September 2021) for organizations adversely affected by COVID-19. ISO 45001 follows the High Level Structure of other ISO standards, such as ISO 9001:2015 and ISO 14001:2015, which makes integration of these standards easier.
