Chemical dispersed pets later (9)
I believe the answer is:
saltpetre
'chemical' is the definition.
(I know that saltpetre is a type of nitrate)
'dispersed pets later' is the wordplay.
'dispersed' indicates anagramming the letters.
'pets'+'later'='petslater'
'petslater' is an anagram of 'SALTPETRE'.
(Other definitions for saltpetre that I've seen before include "Constituent of gunpowder" , "It's used as a fertilizer and explosive" , "Gunpowder ingredient" , "Nitre" , "Component of gunpowder" .)