There is no certification scheme available for NTA 8620. The government itself is required to supervise implementation of the safety management system, since having one is a legal requirement for Seveso companies. This is a major difference with an organization’s environmental or OHS (occupational health and safety) management system, the implementation of which takes place at the initiative of the organization itself.
However, there are companies who want to know for themselves how good their safety management system is, for example as preparation for an inspection. These companies have a certification body evaluate their system using the NTA 8620 as a basis. This can be combined with an ISO 14001 audit. Several certification bodies have auditors on staff who have worked at or for a company with Seveso II directive requirements and are thus qualified to evaluate the safety management system.