▁that ▁labor atory ▁and ▁field ▁testing ▁( some ▁of ▁the ▁latter ▁using ▁sim ul ants ▁on ▁non - cons ent ing ▁individuals ) ▁had ▁been ▁common . ▁The ▁official ▁policy ▁of ▁the ▁United ▁States ▁was ▁first ▁to ▁d eter ▁the ▁use ▁of ▁bio - we ap ons ▁against ▁U . S . ▁forces ▁and ▁second arily ▁to ▁ret ali ate ▁if ▁d eter rence ▁failed . ▁ ▁In ▁ 1 9 6 9 , ▁President ▁Richard ▁N ixon ▁ended ▁all ▁off ensive ▁( i . e ., ▁non - def ensive ) ▁aspects ▁of ▁the ▁U . S . ▁bio - we ap ons ▁program . ▁In ▁ 1 9 7 5 ▁the ▁U . S . ▁rat ified ▁both ▁the ▁ 1 9 2 5 ▁Gene va ▁Pro tocol ▁and ▁the ▁ 1 9 7 2 ▁Bi ological ▁We ap ons ▁Convention ▁( B W C ) — intern ational ▁treat ies ▁out law ing ▁bi ological ▁war fare . ▁Rec ent ▁U . S . ▁bi ode f ense ▁programs , ▁however , ▁have ▁raised ▁concerns ▁that ▁the ▁U . S . ▁may ▁be ▁purs uing ▁research ▁that ▁is ▁out la wed ▁by ▁The ▁United ▁Nations . ▁ ▁History ▁ ▁Early ▁history ▁( 1 9 1 8 – 1 9 4 1 ) ▁Initial ▁interest ▁in ▁any ▁form ▁of ▁bi ological ▁war fare ▁came ▁at ▁the ▁close ▁of ▁World ▁War ▁I . ▁The ▁only ▁agent ▁the ▁U . S . ▁tested ▁was ▁the ▁to x in ▁ric in , ▁a ▁product