Which categories should i put my question regarding occupational safety and health?

Answer 1

Depends on what you are asking but i would say either the
other-health category or careers and employment category cuz it has to do with working.

Answer 2

This category would be fine. Perhaps if the OH&S is something more specific like a disease related to an occupation you could put it on the diseases section of health

The other area might be "Business& Finance > Careers & Employment" section.

For example a question like
"Is an employer liable for paying compensation for mesothelioma if they no longer exist?" would be in the finance section >insurance section .