Final answer:
The final review and signature on all PHAs and applicable documentation are carried out by a responsible official within an organization with the requisite authority, such as a safety manager or operations manager.
Step-by-step explanation:
In the context of Process Hazard Analysis (PHA) within industrial and organizational settings, the final review and signature on all PHAs and applicable documentation is usually performed by a responsible official within the company, such as a safety manager, process engineer, or operations manager. This individual would be someone who has the authority to ensure that all safety and regulatory requirements are met before the PHA is considered complete. In some cases, there may be a requirement for higher-level sign-offs such as from corporate executives or plant managers, especially when significant risks have been identified or substantial changes to the process are recommended.