Management of Change (MOC) is one of the essential elements in maintaining the operational integrity of facilities and preventing major accidents.

Many industrial accidents in facilities are due to poorly managed changes in procedures or installations. These changes may have been intentionally introduced or may be the result of a gradual drift in process conditions, facilities, procedures or organization. One of the critical aspects of managing change is understanding the safe operating limits and organizational aspects of facility management. Critical roles in facility management must be identified and responsibilities must be clearly defined.

A robust MOC procedure is an important element of an organization's QHSE&S management system. 
The objective is to ensure that changes are managed, and major accidents are prevented. Different organizations can vary greatly, and it is not possible to describe the management of the change process and procedures in all detail in a single standard.

The minimum contents of a MOC procedure are:

• Initiation of a change or Request: a change request can come from different sources (from Research, Sales, Marketing, Engineering, etc.). The procedure must indicate how changes are to be initiated
• Responsibilities and authorizations: change requests must be considered, designed, reviewed and implemented or rejected. Responsibilities and authorizations must be identified and documented in the MOC procedure
• Resources: personnel involved in the MOC process must have sufficient knowledge (level and competence). The required knowledge and competences must be identified. A change must be reviewed and approved by several people with the necessary competences who are relevant to consider the impact of the change.  
• Risk assessment: the selected risk assessment must verify that the change does not compromise the critical QHSE&S elements of the operation, e.g. exposure to hazardous substances, environmental impacts, fires and explosions risks, level of education/experience, required maintenance, etc.   If the change requires operating outside established safety boundaries, a more detailed risk analysis must be undertaken to determine the effects of a proposed change on the safety of a process
• Implementation: changes must be implemented correctly. This requires that the people responsible for implementation are provided with the correct and documented information. This information should include the conditions under which the change was approved, the required training of personnel and any permit issues. The implementation also covers safe start-up: the procedure must address pre-start-up safety checks.