The 2015 edition of NFPA 70E has eliminated the Prohibited Approach Boundary (PAB). In part, because there wasn't any additional action required to be taken once you cross it.

Other than including the PAB on arc flash labels and referencing it in the electrical safety program as "the same as making contact with the electrical conductor"

Did you have any special requirement regarding the Prohibited Approach Boundary?

No
Yes (please elaborate)

I hadn't really thought about it that way but you are right. We only referenced it on labels and in the electrical safety practice as the same as making contact. That was it. I guess it makes sense to delete it. Except it will be on our labels for a while.

The prohibited approach boundary is the distance that untrained workers must be kept away from the live items to preventinadventant contact. Untrained workers should only be brought closer then this boundary with proper supervision. This was discussed at one NFPA class. Generally. when working with live equipment, warning tape [Danger Live Equipment - Do not Enter] and cones should be around the area to prevent bystanders and untrained people entering the area where they can contact live equipment.

I liked that 1 inch (Prohibited Approach Boundary) gone than Hazard Risk Category "0".

You are describing the Arc Flash Boundary. You might want to check your notes.

This was a good change, because there wasn't any additional action required to be taken once crossed it was difficult to explain the significance of this boundary.