in accordance to the rules of making precise what i know is that one has to omit the examples. but here in original text it seems that only introduction to the use of chemical and biological toxins have been given., if i were to precise this passade i would have gone in following manner.

chemical toxins were first used in world war 1. the iraqis and russians used chemical toxins against kurd and Afghan Mujahideen & Chechen respectively. use of such toxins damages eniviroment and the use of toxins in Indo-china war by U.S.A is quotable example.

i m not authority on precise . i did it to my best.

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