PetroStreet

How to categorize that what incident is a high potential incident?
Tell me some guidelines both for occupational & process safety please.

Yes. A High Potential Incident is generally an incident where the actual outcome was less severe than it could reasonably have been, but the credible worst-case outcome could have resulted in a fatality, multiple serious injuries, major fire/explosion, significant environmental impact, or major asset damage.
Classify based on credible potential consequence, not only the actual consequence.

That majorly depends that how a risk matrix for a company is applied and what is considered high.
Any incident having a potential severity to causes higher consequence is HiPo in very simple terms.
In our case, whatever is considered to potentially cause a single fatality is HiPo on HSE consequence basis.

Let me put that in this way:
A High Potential Incident is an unplanned event, including an actual incident or near miss, where the credible worst-case consequence under reasonably foreseeable circumstances could have resulted in a fatality, permanent/life-changing injury, multiple serious injuries, major fire or explosion, significant loss of containment, or other major accident consequence, regardless of the actual consequence.