What is Management of Change (MOC)?

What MOC requires

Under 1910.119(l), employers must establish and implement written procedures to manage changes (except for “replacements in kind”) to process chemicals, technology, equipment, and procedures, and changes to facilities that affect a covered process. The procedure must address:

• The technical basis for the proposed change
• The impact of the change on safety and health
• Modifications to operating procedures
• The necessary time period for the change
• Authorization requirements for the proposed change

Additionally, employees involved in operating a process — and maintenance and contract employees whose job tasks will be affected by the change — must be informed of and trained in the change before start-up of the affected part of the process.

“Replacements in kind” versus changes requiring MOC

A replacement in kind is a replacement that satisfies the original design specification — for example, replacing a failed valve with an identical valve from the same manufacturer with the same pressure rating, materials of construction, and size. Replacements in kind are explicitly exempt from MOC.

If any specification changes — a different manufacturer with slightly different internals, a different pressure class, a different material of construction, a different size — it is not a replacement in kind and requires a formal MOC.

The integration with other PSM elements

MOC does not exist in isolation. Every change that triggers MOC typically requires updates across multiple PSM elements:

• Process Safety Information (PSI) — P&IDs, equipment specifications, and related documentation must be updated
• Operating procedures — any procedure affected by the change must be revised
• Training — affected personnel must be trained on the change before start-up
• Process Hazard Analysis — if the change is substantial enough to affect process hazards, a PHA revision may be required
• Mechanical integrity — if the change affects equipment subject to mechanical integrity requirements, the MI program must be updated
• Pre-Startup Safety Review (PSSR) — formal review before restart

Why MOC is frequently cited

MOC is among the most frequently cited PSM elements in OSHA enforcement actions. The reasons are operational: changes happen continuously in an operating facility, each change has its own documentation and training burden, and the cumulative load of maintaining rigorous MOC on every modification is significant. Gaps in MOC documentation — particularly in updating P&IDs to reflect post-change as-built conditions — are a predictable finding in OSHA audits.

The P&ID challenge in MOC

Every MOC that affects physical equipment or piping requires updating the governing P&IDs. In most facilities today, this is a manual process: the current P&ID is printed, changes are redlined by hand, the red-lined drawing goes to a drafter who updates the master, and the updated P&ID is filed in the PSI package.

The practical consequence is that P&IDs typically lag the physical facility. Undocumented field modifications drift into the as-built condition. The longer this gap persists, the more expensive it becomes to close — and the more exposed the facility becomes to MOC audit findings.