In terms of contemporaneous, if an OHS Inspector is taking notes on an official investigation what is an acceptable time frame for s/he to adjust the notes to correct errors while at the scene i.e names, locations, job title.
Polly, there isn't a specifically delineated time period for these notes, but if one is interested in maintaining the integrity of the investigation, they should be taken during the investigation. If the investigator is visiting a job site, for example, it would be preferable that his notes are taken in real time, as he interviews individuals, etc. Simply put:
A decision-maker that needs to make a finding of fact will prefer the credibility of a person whose evidence is supported by contemporaneous record, where everything else is equal.
As I'm sure you're aware, these investigations may at any time lead to administrative charges or litigation. Thus, the longer an inspector waits to conclude them, the higher the risk he runs of his testimony being impeached at a later trial or hearing.
Regarding making changes to the notes, the best option is not to do that. Should it be required, the original version should be retained as well.
For a practical example of the importance of contemporaneous notes, check this article out: https://www.lexology.com/library/detail.aspx?g=b0e1813f-9c9f-49e7-8c75-27f2f881ece3. (Note: you have to create a Lexology account to view it, but it is free!
This is another great narrative which approaches from a different angle.
What are realistic time limits on contemporaneous note taking?
It is highly doubtful that any legislation would prescribe time limits for that, let alone while the inspector is at the scene. If anything, such limits would be superseded by the need for accuracy of the inspector's findings.
The purpose of inspections is to ascertain compliance by, or conditions of, the investigated entity[-ies], not the inspector's dexterity in taking notes that wouldn't warrant edits sometime later.