Fool about to produce gunpowder ingredient (5)
I believe the answer is:
nitre
'gunpowder ingredient' is the definition.
(I've seen this before)
'fool about' is the wordplay.
'fool' becomes 'nit' (I've seen this before).
'about' becomes 're' (regarding**).
'nit'+'re'='NITRE'
'to produce' acts as a link.
(Other definitions for nitre that I've seen before include "explosive producer?" , "found in a slow match?" , "food preservative" , "explosive ingredient" , "Inert (anag) - saltpetre" .)