There are many companies around the world that create and issue standards, two of these are the British Standard Institute (BSI) and the International Organization for Standardization (ISO). ISO has issued the ISO 45001 standard, and BSI had issued the OHSAS 18001 standard. While the ISO organization has countries from around the world vote on the standards it releases, an organization like BSI does not. As such, the ISO standards are recognized around the world as the best practice in the international community. By comparison, the BSI standards are recognized by some countries but not others.
For a comparison of what will happen it is helpful to loo k at the ISO 14001 standard. This was also a different BSI standard before it was adopted by ISO. Once the ISO standard was issued the BSI standard was made obsolete shortly after the fact and no longer updated. The same thing is expected to happen here, the ISO 45001 standard has become the internationally recognized standard, and BSI will make the OHSAS 18001 standard obsolete, at which time certification bodies will not audit against this standard and OHSAS 18001 will not have any other releases. There has been no merger of companies, just that the standard for occupational health & safety is now internationally recognized in ISO 45001. The BSI organization does much more than just maintain standards, and will continue to exist for many other reasons.
To help transition from OHSAS 18001 to ISO 45001 I suggest looking into our whitepaper, “Twelve-step transition process from OHSAS 18001 to ISO 45001”, https://info.advisera.com/45001academy/free-download/twelve-step-transition-process-from-ohsas-18001-to-iso-45001