What would chemistry seniors like to hear about industrial hygiene?
To keep this answer as far from opinionated as possible, I'd suggest some of the W's:


What is industrial hygiene? (I've never heard of the term before this post and actually had to look it up myself.) 
How do you do industrial hygiene? Procedures, risk assessment...
Why is industrial hygiene important? You might give examples where disaster was averted thanks to IH, and an example where it would have helped if done right.
Where is industrial hygiene applied? (I guess the office building will have less rigorous guidelines than the production facility.)
When did industrial hygiene start to be a thing? A small historical overview could be given, you could even give a who to this one if it was some distinct person who came up with the idea.


Always good is a personal anecdote, something you witnessed or someone (whom you trust as a source) told you, highlighting the bullet points above.