PHA Overview (Part 1)


A PHA is the cornerstone of an effective PSM Program.

In the next several blogs, we will consider various aspects of PHAs to help improve understanding regarding this important process safety activity.

What is a PHA?

A process hazard analysis, or PHA, is an organized and systematic effort to identify, evaluate, and control potential hazards associated with the handling of highly hazardous chemicals. In short, a PHA is a study of risk. Both EPA’s Risk Management Program (RMP) and OSHA’s Process Safety Management (PSM) regulations require PHAs to be performed on chemical processes subject to their respective regulations. Unsurprisingly, in California, the CalARP and CalOSHA PSM regulations also require PHAs to be conducted. PHAs must be facilitated by a qualified leader who will steer the PHA team in assessing the risks associated with the process or processes being analyzed.


PHAs must be performed initially, before a new chemical process is commissioned, and updates or revalidations are required at least every five (5) years.

Title 40 CFR §68.67(f)

At least every five (5) years after the completion of the initial process hazard analysis, the process hazard analysis shall be updated and revalidated by a team meeting the requirements in paragraph (d) of this section, to assure that the process hazard analysis is consistent with the current process.

The text above was copied from the RMP regulation, but PSM and CalARP have nearly identical requirements.

In addition to the five (5) year frequency, it is appropriate to perform or update a PHA when a system undergoes a major change that introduces new hazards that were not considered in a previous PHA.

Hazard Review

It is worth mentioning that processes with smaller chemical inventories may only be subject to the Program 2 requirements of RMP or CalARP. When this is the case, the facility owner is required to conduct a Hazard Review (HR) in lieu of a full PHA. While we acknowledge that there are fewer prescriptive requirements for HRs compared to PHAs, many firms that conduct PHAs and HRs follow the same protocols for both, and often use the expression ‘PHA’ in either instance.

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