An Evergreen Process Hazard Analysis Will Help You


Those who work in high hazard industries are familiar with the OSHA Process Safety Management (PSM) standard requirements for Process Hazard Analyses (PHA) for their covered processes. These studies are required to be completed initially, then revalidated, typically on a five-year schedule. Good practice implemented at many companies is to follow a similar scheme for processes containing hazardous materials that are not covered by the standard.


During revalidation PHAs, among other things, it is expected that any changes or new learnings (from incidents, for example) for the area under study will be incorporated so that the study represents the state of the process at the time of the PHA. It is also expected during revalidation that resolution of prior recommendations will be verified and any safeguards that have been improved or implemented will be integrated and documented. Collecting, reviewing, and incorporating five years’ worth of changes, learnings, and updates to recommendations and safeguards for the process can be challenging and very distracting to a PHA revalidation team.


An alternate method of managing PHA review of changes and learnings to a process is to incorporate them into the PHA as changes are underway or learnings occur. This method is often called an Evergreen PHA or Continuous PHA Revalidation.


The Benefits

Evergreen PHAs have valuable benefits, including:

- It is a big time saver at revalidation time since changes, learnings, and the status of recommendations and safeguards are current

- The PHA is always current for internal reference, as well as for auditors or regulatory agencies

- The PHA always matches the current P&IDs for the process

- The preexisting PHA helps teams who are assessing changes to a process to not go beyond the scope of the change and not to issue “wish list” recommendations that are not truly needed to mitigate risks. MOC PHA teams who have a model in an evergreen PHA are more likely to focus on the task at hand.

- The preexisting PHA helps teams who are assessing incidents to rapidly translate incident learnings into the PHA in a way that works to align the incident root & contributing causes and consequences with existing information in the PHA. It is most efficient to accomplish this work while the incident investigation participants have the information fresh on their minds, rather than asking a revalidation PHA team to accomplish it perhaps years later.


The Challenges

Evergreen PHAs are a concept that sounds appealing on the surface, and they do indeed provide many safety and resource benefits. Many sites successfully manage their evergreen PHA in a way that allows them to obtain the maximum benefit from the practice. But if improperly managed or executed, “not so evergreen” PHAs can suffer from failures such as lack of control of the master file and archived files, lack of a designated “owner” of the file, failure to track file updates, or failure to include a change, learning, or updated action status at the right time. These flaws can all lead to confusion and difficulties in management of the PHA. This in turn can lead to suboptimal use of people’s time and in the worst case, misunderstandings about the process hazards and their safeguards. This has the potential to lead to safety gaps and even process safety incidents.


Get Off on the Right Foot

Start your evergreen PHAs off right by incorporating good practices and good usage discipline in your PHA program, including:

- A single designated storage location and “owner” for the file(s)

- A narrative, ideally embedded in the PHA file, clearly describing the changes from the baseline or most recent revalidation PHA with relevant MOC, project, and incident references included

- Revision tracking methods, including for the file, the nodes that were revised, new safeguards and recommendations, and even the scenarios that were added or revised

- Predetermined conventions for how new or revised scenarios and safeguards should be marked as revisions

- A tracking method for the status of recommendations and proposed safeguards

- A tracking method for new recommendations developed during changes to the baseline PHA or most recent revalidation

- A predetermined method for how to incorporate future changes that may be implemented at different times, for example turnaround projects vs. projects that are expected to be completed while a process is running

- Retention of old file versions, in the event that a change is canceled before implementation

- Provision of updated documentation from the updated PHA to affected staff

- A method to familiarize affected staff with the changes made to the baseline PHA or revalidated PHAs


If your software product does not currently support the evergreen PHA concept, help is available to improve your templates and even to manage your files and the incorporation of changes in many cases. Properly managed evergreen PHAs can go a long way toward increasing the value of, and your confidence in, one of your most important process safety program elements. Tackle it soon!


by Judith Lesslie, CFSE, CSP

Process and personal safety professional with more than 35 years’ experience in HSSE leadership, process safety and instrument engineering, project management, and maintenance in the petrochemicals industry.

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