A Process Hazard(s) Analysis (PHA) is a great tool to look at an entire process, and a Job Hazard Analysis (JHA) is a great tool to use to analyze the hazards within specific tasks within the covered process. They are different tools for different scopes of work, but they can work in unison to make the process and the work within the process much safer. This is how I have been using both tools for the past 30+ years.
A PHA is a tool to examine what can go wrong within a process. Some may say the PHA is a 30,000-foot view of the process hazards; I do not like saying that, as a well-performed PHA can get much more detailed than the 30,000-foot view.
The JHA is a tool we use to analyze the tasks within the covered process.
For example, a PHA will cover “Truck and Railcar Unloading or Loading”. We will use one of the recognized methodologies to study the opportunities for a Loss of Primary Containment (LOPC), such as hose failure, overflowing a tank, overpressuring a tank, mixing chemicals (Wrong Chemical to Wrong Tank), etc. But once we are done with the PHA, someone will need to write an SOP to unload/laod those tankers/Railcars and for this scope of work, we can use the JHA tool to analyze each necessary step to complete the task. The JHA will allow us to identify “hazards” within each step and to identify necessary safeguards for the step.