2) Avoid Making Changes Without an MOC

1. On October 9, 2012 a flash fire caused burn injuries to seven workers, including three who sustained third-degree burns at the US Ink/Sun Chemical Corporation ink manufacturing facility in East Rutherford, New Jersey.  Workers were drawn to a black ink mixing room by the initial flash of the fire from a bag dumping station and by a loud thumping noise from the rooftop. As the workers congregated at the doorway, they observed a small fire in the ductwork of a newly installed dust collection system above a process mixing tank. Suddenly, a large flash fire emerged from the pre-mix room and engulfed the seven employees in flames. A new dust collection system had been commissioned 4 days before the incident.  An MOC was not written for this new dust collector system as engineers and senior management considered the dust collector system as a replacement in kind for the old wet scrubber system.   In addition to not having written an initial MOC for the change, the original design of the dust collection system was modified.  The original design was intended strictly for dust collection but was modified before commissioning to include vacuum cleaning function.  This cleaning function had insufficient flow rate which restricted air movement and contributed to an accumulation of hazardous materials in the duct system.  (2)
2. On June 1, 1974, the Nypro cyclohexane oxidation plant in Flixborough, England was destroyed by a vapor cloud explosion. The incident occurred by a release cyclohexane to the atmosphere which formed a vapor cloud that was ignited by an unknown source. The explosion that resulted destroyed the entire plant and resulting in the death of 28 people and injuring 89 others. The effects extended beyond the plant into the surrounding community with over 1,800 houses and 167 businesses damaged. The explosion event was initiated from a temporary change. Plant personnel had decided to temporarily bypass a reactor which was leaking and continue the process.  However, the changes were done hastily and there was no MOC process in place, If an MOC system had been in effect at the plant, it would have called for a proper safety review, adequate approval at all stages of the change process, and a design to the same standards as the original design. (3)

1. Reasons the MOC system is being deployed
2. The reasons for a strong and consistent MOC system
3. Management expectations for MOC conformance, including the responsibilities for the various roles under the MOC program
4. Case studies of incidents where MOC was a contributor are described.  This should also include local incidents and near misses where lack of or incomplete MOC was a contributor, and the findings of audits and other evaluations of the MOC program are reviewed.  (1)

Follow the written MOC process.

1. ​​​​An MOC should be written in advance of making the change to allow for proper review and approval.  MOC should not be used as a documentation tool after the fact.​​​​​​​​​​​​​​​​​​

2. The review of the impact of the change on safety and process safety is the most important part of the MOC process. This review helps identify the key aspects of understanding risk and hazards presented by the change. (1)   
   1. The MOC procedure in each facility should specify a level of hazard review that is commensurate with the prospective risks.  A considered, independent, knowledgeable decision on whether the proposed change should be subject to a PHA should be part of the process.  If this is not considered necessary, then another form of documented hazard/safety review should be performed.  (1), (6)
   2. The use of checklists or other methods should be incorporated into the process so that this step is consistent and documented. (1)
   3. MOC Reviews can be performed 1) via in-person meetings , 2) individually in isolation, or 3) a combination of both  (1)
      1. With the advent of electronic MOC systems the review-in-isolation process has become more prevalent.  This isolation can lead to lack of understanding of the change and missed hazards.
      2. The person who performs or approves the safety and health review should be independent of the requestor whenever possible.
      3. The MOC approvers should be independent of the requestor whenever possible.
      4. These MOC reviews should also include technical reviews and ensure those who are most knowledgeable of the process are included.
      5. When MOC reviews are performed using meetings care should be exercised  to ensure that participants are not pressured to agree with others.

1. Develop performance indications and data collection to evaluate the status and implementation of the MOC system. For example, an audit of work orders to determine if work orders that required MOC received them.  (4).
2. Incidents and near misses should be reviewed to gauge the strength of the MOC system and identify improvements.