[QUOTE[b=left]Why would one need this gear[/b]][/QUOTE]
In the words of the Fireman giving fire training to a Vigilant VGS. "Man-made Mineral Fibres". You don't want any of the small pieces of glass/carbon/boron fibres that they make modern aircraft from getting into your lungs, especially if they are also coated in the nasty products of combustion.
Its probably the reason why we decided that if a Vigilant crashed and burnt we would all stand well up wind and watch, waiting for the fire service to arrive rather than attempt to fight the fire ourselves. HQAC never having thought to issue respirators for the VGS staff they expected to provide fire cover