Management Systems
How Management of Change Works as a Process Safety Control
Vinit Pandey · Published 4 August 2026
In short: Management of Change (MOC) is a process safety management element requiring that any modification to process technology, equipment, procedures, or personnel is reviewed and authorised before implementation, so that new hazards introduced by the change are identified and controlled.
Key takeaways
- MOC scope includes procedure, control logic, and personnel changes, not only physical equipment changes
- A working MOC system distinguishes 'replacement in kind' from changes requiring genuine hazard screening
- Review level should be proportionate to the change's potential hazard impact
- Inadequate MOC is a repeatedly cited root or contributing cause in process safety incident investigations
The scope of MOC covers more than physical equipment changes: process chemistry adjustments, operating procedure revisions, control system logic changes, and even temporary staffing changes in safety-critical roles can all introduce new hazards requiring review.
A functioning MOC system distinguishes between a 'replacement in kind' — where a component is replaced with an identical or equivalent part requiring no further review — and a genuine change requiring hazard screening, since treating every minor replacement as a full MOC review would make the system unworkable in practice.
MOC screening typically routes a proposed change to a level of review proportionate to its potential hazard impact: a minor documented check for low-impact changes, up to a full HAZOP or LOPA revalidation for changes affecting safety-critical process parameters or safety instrumented functions.
Incident investigations across the process industries repeatedly identify inadequate MOC — changes implemented without proper hazard review, or temporary changes that became permanent without re-evaluation — as a root or contributing cause, making MOC discipline one of the highest-leverage process safety management elements.