Most industrial processes operate under a delicate and necessary balance of administrative and engineering controls to ensure that a facility can operate safely and efficiently. In the design stage, countless hours are spent defining critical process parameters, such as electrical infrastructure, material suppliers, and facility siting. Oftentimes many complex hazards of different types must be identified and addressed concurrently. When a facility becomes operational it becomes apparent that additional changes to procedures, process setpoints, and other parameters are required in order to reflect the real-world operating conditions. However, from commissioning onward, it is essential that all changes are thoroughly evaluated to ensure that the changes do not inadvertently introduce new hazards or worsen existing ones¹.
Figure 1: Process Safety Management Pillars²
To help facilities navigate the complex changes and decisions required throughout the life of a process, a management of change (MoC) system is typically utilized to help manage risk, as illustrated in Figure 1. According to the Center for Chemical Process Safety, a MoC system “includes a review and authorization process for evaluating proposed adjustments to facility design, operations, organization, or activities prior to implementation”¹. MoC systems are often tailored to each facility, taking the physical and/or digital form that is most convenient and effective for the facility and its personnel. The level of intricacy and depth required for a system is dictated by the hazards that must be managed. At its core, a robust system should ensure that:
- Proposals to make the changes are submitted to a formal review and approval process
- Hazards and risks associated with the proposed changes are identified and analyzed
- Decisions are made on whether to accept the change with the given constraint
- For approved changes, the risk controls are specified, approved, and implemented
- All relevant process information, procedures, and training are updated and communicated⁴
For both OSHA PSM facilities and NFPA 660 facilities, a MoC system is not just a good idea—it’s a necessary requirement. OSHA PSM facilities refer to CFR 1910.119(l) to define the requirements for the MoC system. Primarily, the system must manage changes related to the process chemicals, technology, equipment, procedures, and the facility itself⁶. Any proposed changes affecting one or more of the previously stated categories requires a thorough review to ensure that the change would not compromise safety at the facility. Per CFR 1910.119(l), the review must consider the technical basis, the impact of change on safety and health, any required modifications to operating procedures, the duration of the change, and authorization requirements⁶.
NFPA 660, the Standard for Combustible Dusts and Particulate Solids takes a similar approach to the Code of Federal Regulations. Chapter 8, Section 11 of NFPA 660 requires a MoC system to consider nine key factors before implementing a change. Those factors are as follows:
- The technical basis for the proposed change
- Safety and health implications
- Whether the change is permanent or temporary, including the authorized duration of temporary changes
- Modifications to operating, maintenance, and emergency response procedures
- Employee training requirements
- Authorization requirements for the proposed change
- Results of characterization tests used to assess the hazard, if conducted
- Implementation of any recommendations required for safe operation of the change before startup
- Confirmation that the change has been implemented per design prior to startup⁵
Both the NFPA and the CFR make exceptions for changes that are considered “replacements in kind”. These replacements are either identical items or alternatives that meet the exact technical specifications of the original. Replacement in kind (RIK) can be deceptively simple. Often when the technical requirements are incomplete or vague, the RIK may fall short of the original design requirements. For example, when replacing a burnt-out motor, it may seem straightforward to find a motor of identical phase, power, physical size, etc. However, if the replacement motor does not meet the less obvious requirements, such as T-code temperature ratings or ventilation needs, it may create a new ignition source for flammable or combustible materials. If the original design specifications omitted T-code or ventilation requirements, the critical safety consideration for a piece of equipment could be easily overlooked. Management and maintenance personnel should not be misled by the apparent simplicity of RIK. Only qualified and knowledgeable personnel should approve replacement in kind to ensure that all technical aspects of the change truly meet “in kind” criteria.
MoC systems can seem cumbersome or excessive; however, the diligent review of changes is essential when processing or handling hazardous substances. The tragic 2022 incident at the BP-Husky Refinery in Oregon, Ohio, serves as a powerful reminder of the importance of MoC. The refinery incident occurred on September 20th, 2022, when the inadvertent release of naphtha created a vapor cloud that ignited, fatally injuring 2 brothers who worked at the plant. The incident is now BP’s most significant incident since the explosion and fire at the Texas City refinery³. The event was triggered by the overflow of water into a naphtha standpipe. The addition of water to the naphtha stream caused naphtha to rapidly accumulate in subsequent vessels. The sequence of events escalated as a naphtha overflowed into a vapor bypass line and began filling a fuel gas vessel. As the fuel gas vessel began to overflow, operators were instructed to open the vessel and release naphtha onto the ground. The resulting vapor cloud eventually found an ignition source and ignited in a flash fire, killing both workers³.
What could have been a much smaller incident was worsened by the plants lack of preventive and mitigative safeguards for the “Absorber Stripper Tower to the Fuel Gas Mix Drum” scenario. This scenario could have been avoided, Figure 2: Crude 1 Overhead Accumulator Drum water phase level before water control valve adjustment (top) and during water carryover into naphtha stream (bottom)³ had management of change procedures been thoroughly executed. Six weeks prior to the incident, the facility underwent a turnaround. During that turnaround, the water phase level indicator in the Crude 1 Overhead Accumulator Drum was changed³. While the primary function of the old and new level sensors was the same, the change was not a “replacement in kind”, due to differing calibration technologies. As shown in Figure 2, the new sensor indicated overflow at 69%, whereas the old sensor would have shown it at 100%. This change in level indication was not communicated to operators. As a result, when the water level reached 69% during a manual adjustment of the Crude Overhead Accumulator Drums, operators were unaware of the hazard and the cascading events that would follow3. The operator’s lack of awareness of the abnormal water level prevented them from identifying it as the cause of the overflow. Had appropriate management of change procedure been followed, this sensor technology change would have been clearly communicated to all affected personnel. Additionally, procedures and SOPs should have been revised to reflect the change and guide operator response.
The safe and efficient operation of industrial facilities hinges on the continuous and careful Management of Change. While engineering and administrative controls lay the foundation for safety, it is the ongoing vigilance through a robust Management of Change (MoC) system that sustains it. As demonstrated by the tragic BP-Husky Refinery incident, even seemingly minor changes, such as a sensor replacement, can have catastrophic consequences if not properly evaluated and communicated. MoC is not merely a regulatory requirement under OSHA PSM and NFPA 660; it is a critical safeguard against the unintended consequences of change. Facilities must treat every proposed modification, including replacements in kind, with the rigorous scrutiny it deserves. By fostering a culture of thorough careful review, transparent communication, and technical diligence, organizations can prevent incidents, protect lives, and uphold the integrity of their operations.
Need Support with Your Management of Change Program? Fauske & Associates supports facilities in developing and refining Management of Change (MoC) programs tailored to meet OSHA PSM and NFPA 660 requirements. Contact us today to learn how we can support your facility’s change management needs.
References
- Center for Chemical Process Safety. “Introduction to Management of Change.” www.aiche.org, 11 Dec. 2012, www.aiche.org/ccps/introduction-management-change
- Center for Chemical Process Safety. Risked Based Process Safety Overview;
American Institute of Chemical Engineering, 2011. - Chemical Safety Board (CSB), Fatal Naphtha Release and Fire at BP-Husky
Toledo Refinery, Oregon, Ohio, Inc. No. 2022-01-I-OH, Published June 2024 - Drago, J.P.; Vaughen, B.L. Management of Change Systems: What Does Good
Look Like? Presented at 2025 Spring P2SAC Conference, West Lafayette,
Indiana, May 7, 2025. - NFPA 660, Standard for Combustible Dusts and Particulate Solids (Quincy:
National Fire Protection Association, 2025) - Occupational Safety and Health Standards, 29 C.F.R. § 1910.119 (2025)