One weakness of most hazard evaluations identified 30 years ago still exists in the majority of PHAs performed around the world. Most PHAs do not thoroughly analyze the errors that can occur during startup, shutdown, and other non-routine (non-normal) modes of operations. Sadly, the commonly used approaches for PHA of continuous mode of operation only find about 5 – 10% of the accident scenarios that may occur during startup, shutdown, and online maintenance. This is despite the fact that about 70% of major accidents occur during non-routine operations.

imageMany companies have taken small steps to evaluate hazards of non-routine operations by tweaking HAZOP nodes to include deviations of “Startup” and “Shutdown” to each node. This has proven inefficient based on data from the following sources:

  • Comparison of analysis results with & without PHA of non-routine procedures
  • Number of missing safeguards found when procedures are finally analyzed in the last phase of major capital projects
  • Evaluation after accidents that have occurred during non-routine modes of operation (the accident scenarios that occurred were NOT identified in the PHA of normal mode of operation)


The methodology for hazard evaluation of non-normal operating modes will typically include one or both of the following techniques:

  • WHAT-IF analysis of procedures – an unstructured brainstorming method without utilization of guide words to uncover potential accident scenarios
  • 2 Guide Word HAZOP analysis of procedures – a structured “WHAT-IF” analysis utilizing guide words (i.e., step not performed, step performed incorrectly).

These are then supplemented by use of a Checklist of Human Factors Issues – a checklist used to indicate where generic weaknesses exist that can make errors during any mode of operation more likely, or that can make errors during maintenance more likely.

Increasing Regulatory Pressure

OSHA – The US OSHA PSM regulation requires PHA of all hazards during all modes of operation, and several key citations since 1990 have focused on PHA of non-normal modes. OSHA has announced they are increasing focus on PHA of non-routine modes of operation by adding new guidance to OSHA inspectors (2016). (Reference Necessity of Performing Hazard Evaluations (PHAs) of Non-normal Modes of Operation (Startup, Shutdown, & Online Maintenance) written by Mike Marshall

[OSHA Enforcement Chief] and William Bridges [PII]).

US CSB – The US Chemical Safety and Hazard Investigation Board (US CSB) has commented on the need for PHAs to address all hazards of the process during all modes of operation. Their clearest statement was in the report 2008-08-I-WV-R113 on the Bayer CropScience accident in Institute, WV, 2008 where they listed lack of PHA of non-routine modes of operation as the major factor of this catastrophe.

EPA – In the Risk Management Program rule (40 CFR 68.24) EPA also recognizes the importance of procedural analysis, by defining the purpose of a PHA to “examine, in a systematic, step-by-step way, the equipment, systems, and procedures (emphasis added) for handling regulated substances.”

PII can help your organization overcome the gap of no “PHAs of Non-normal Operating Modes” by:

  • Leading and documenting PHA of procedures for new processes/tasks
  • Leading and documenting PHA of procedures for existing (older) processes/tasks
  • Training and then Coaching your PHA leaders through their first PHA of procedures

PII also offers courses related to leading PHAs (including non-normal modes) (see courses 8, 8-0 and 9 under the “Training” tab or click on the individual links below):

In addition, feel free to download papers written by PII staff related to PHAs/HAZOPs under the “Free Resources” tab (or click on the individual links below):

Why Choose PII?

Customization to Client’s Needs PII finds the best approaches to risk management, process safety management, and reliability management to fit your specific needs and company culture. We deliver the highest value of service by customizing what we do to each client’s need.

Industrial experience of our providers Each of PII’s experts has many years of implementation experience as they worked in the chemical and related industries before becoming consultants and external trainers. Many other consulting companies will sell you services and training from “experts” who have only ever been consultants. This is of little value to you compared to using consultants and trainers who have learned what works and doesn’t work by actual experience in settings similar to yours.

PII Conducts Meetings with Speed & Efficiency. Because of our vast experience spanning 25+ years of optimizing PHA procedures, and with our hands-on expertise in the best software, we can lead meetings faster than anyone else, while maintaining quality/thoroughness. This saves cost for you and your projects.

PII staff use proven methods for fostering brainstorming of deviations for written steps and have learned how to optimize the application of these methods. We wrote the chapter on these methods in the textbook on PHAs (Guidelines for Hazard Evaluation Procedures, 3rd edition, 2008; CCPS/AIChE)

PII staff understand the root causes of human error and the strategies for systematically finding the scenarios that are caused by human error during all modes of operation. This yields thorough analysis results while providing practical allocation of resources.

PII staff are experts at utilizing widely accepted hazard evaluation techniques (such as those referenced by OSHA and EPA for PHAs, which include what-if analysis and hazard and operability [HAZOP] analysis). This strategy has proven effective for hundreds of facilities over the past two decades since it was first published (by PII staff). In addition to identifying accident scenarios during non-routine modes, this approach helps to more fully address human factors, which is a specific requirement of OSHA’s PSM regulations and EPA’s RMP rule.

PII Credentials

•PII has significant experience in leading large project PHAs, unit-wide PHAs, and process specific PHAs and revalidations; PII staff have led or managed/supervised more than 8,000 major PHAs and revalidations; every year we lead more than 100 unit-sized PHAs.

• Thousands have used our training services to become proficient in PHA leadership, implementing process safety management, leading investigations and root cause analysis, and writing effective procedures

•Extensive industry PSM experience and knowledge; PII staff were co-authors of the AIChE/CCPS-sponsored textbooks on PHA methods (Guidelines for Hazard Evaluation Procedures; 2nd Edition, 1992 and 3rd Edition, 2008)

•Extensive knowledge in failure rates and human error probability that helps us to diplomatically break deadlocks on teams. PII staff were primary authors of the AIChE/CCPS-sponsored textbook on the best semi-quantitative risk assessment method (Layer of Protection Analysis [LOPA], 2001 and Guidelines for Initiating Events and Independent Protection Layers, 2015)

•Strong facilitation skills with experience in leading multi-functional teams as part of PHAs and other process improvement projects

•Experience in incident investigation, root cause analysis, and human factors to help the PHA team identify potential causes and effects of incidents. PII staff were primary authors of the AIChE/CCPS-sponsored textbook on Investigation methods (Guidelines for Investigating Chemical Process Incidents; 2nd Edition, 2003)

•Significant experience in revalidating PHAs. PII staff have written about 20 papers/articles on process safety management, including many papers on how to effectively perform PHAs/HAZOPs. We have revalidated hundreds of PHAs around the world.

•Recognized experts in the field of process safety and process hazard analyses. In fact, the founder of PII led the first PHA that was submitted to US OSHA for compliance assessment (in 1991; as part of a settlement agreement between Phillips and US OSHA)

•Inherent capability for training and mentoring of your internal PHA leaders and scribes