▁Vietnam ▁War ▁brought ▁public ▁aw aren ess ▁to ▁the ▁U . S . ▁bi ological ▁weapons ▁program . ▁The ▁use ▁of ▁chemical s , ▁ri ot - control ▁agents , ▁and ▁her b ic ides ▁like ▁Agent ▁Orange ▁drew ▁international ▁criticism , ▁and ▁neg atively ▁affected ▁the ▁U . S . ▁public ▁opinion ▁on ▁the ▁development ▁of ▁bi ological ▁weapons . ▁High ly ▁controvers ial ▁human ▁research ▁programs ▁and ▁open ▁air ▁experiments ▁were ▁discovered . ▁Jean ne ▁Gu ille min , ▁wife ▁of ▁bi ologist ▁Matthew ▁Mes el son , ▁summar ized ▁the ▁controvers y : ▁▁ ▁The ▁N ixon ▁administration ▁felt ▁an ▁ur gent ▁need ▁to ▁respond ▁to ▁the ▁growing ▁negative ▁per ception ▁of ▁bi ological ▁weapons . ▁The ▁real ization ▁that ▁bi ological ▁weapons ▁may ▁become ▁the ▁poor ▁man ' s ▁atom ▁bomb ▁also ▁contributed ▁to ▁the ▁end ▁of ▁the ▁U . S . ▁bi ological ▁weapons ▁program . ▁ ▁Sub sequently , ▁President ▁N ixon ▁announced ▁that ▁the ▁U . S . ▁was ▁un il ater ally ▁ren oun cing ▁its ▁bi ological ▁war fare ▁program , ▁ultimately ▁signing ▁the ▁Bi ological ▁and ▁To x in ▁We ap ons ▁Convention ▁in ▁ 1 9 7 2 . ▁ ▁End ▁of ▁the ▁program ▁( 1 9 6 9 – 1 9 7 3 ) ▁ ▁President ▁Richard ▁M . ▁N ixon ▁issued ▁his ▁" Statement ▁on ▁Chem ical ▁and ▁Bi ological ▁Def ense ▁Pol ic ies ▁and ▁Program s " ▁on ▁November ▁ 2 5 , ▁ 1 9 6 9