Might be a bit different on a carrier deck as opposed to our small little helo deck on my Knox class frigate. But I wore red and sat on the #1 fire hose party. When I asked why the #2 hose party was so far away from the helo deck, I was told that was in case the #1 hose party got blown off the deck. Lol.
Red shirts on a big attack carrier are the armament personnel. They assemble the missle/bomb components and install them and ammo on the aircraft. When they move anything nuclear, they are escorted by Marines with automatic weapons.
I served as a green shirt in catapults. The other half of our division was arresting gear. My boss was the division CDR who was the yellow shirt shooter.