dizing agent is selected from the group consisting of oxygen in its triplet or singlet states; ozone; hydrogen peroxide; hydroxyl radical precursors; compounds of formula XYOz wherein z varies from 1-4, X is an alkali metal or alkaline earth metal and Y is a halogen; chlorine, bromine or iodine, or any precursor thereof; aqua regia; a heavy metal oxidant: Caro's acid; oxones; mono and persurfate d