Tommy, can you hear me?

Our deaf seasonal employee (second year he has worked here) just walked by my office, speaking very loudly. I stupidly wondered why he was speaking so loudly. After all, we already have Ob and Sub for that. Then I realized that, being deaf, he has no concept of volume control. So, I wondered to myself, if he's already deaf, do we need to provide him with earplugs when he operates equipment like backpack blowers or weedwhackers?