Not sure if I'm getting my games mixed up here, but in either SRTT or SRIV, the suit is available in Let's Pretend as a Firefighter suit. The Hazmat Headpiece however is only available in SRIV.
It's also possible that I'm completely wrong, and they both were only made available in the games through mods.
But the Suit and Headpiece are still separate entities, as it is used in Tour De Farce. When entering the Torbitron, the Headpiece is removed to avoid clipping issues.
Not sure about the gloves, but the boots are just the standard Work Zone Boots from Planet Saints, painted to match the suit's colour.