Besides the
hapless Star Trek versions, there are red shirts in the
US Navy.
The red shirt, accompanied by a red semi-helmet and a red life vest, are the folks who are there in case of a catastrophic emergency. Their job is to put out any fires and to rescue any endangered people, such as pilots or green shirts. Usually there are at least two in full flame-proof silver suits (with the required red shirt underneath, of course).
These sailors are rarely needed, and their job is to sit and wait just in case. They get full flight deck pay allowances, since their job involves hazardous duty. There have been incidents (such as the USS Forrestal) where a crashed aircraft set off multiple bombs and ammunition, which was all captured on tape and is played at every firefighting class. One minute there are folks fighting a fire, then a flash, then just bits of hoses flailing about randomly.
Just like their Star Trek counterparts, they just don't know when something bad will happen.