I was watching this video which was filmed in 1991. I was shocked to see FDNY personnel responding and fighting fires in dungarees. Was there no requirement for full bunker gear then? When did a full bunker gear edict go into effect?
As near as I can tell, the “requirement” specifying exactly what “all” of your gear consists of and mandating its use was in either 1992 or 1997. NFPA 1500 was updated in both of those years, but I don’t have an old copy to take a look at. My department made the switch from three-quarter boots to bunker pants in 1997, so I would suggest it was the '97 edition. It could have been the '92 edition and we were just five years behind, but I seriously doubt it.
Whether a department chooses to follow NFPA 1500 is their own business, though. There is no nationwide law that says “you will follow all NFPA standards.” Some states have such laws, but not everyone does. I don’t know what FDNY does, but they do some things, out of necessity, quite a bit different than everyone else.