Iraq purchased 8 strains of anthrax from the United States in 1985, according to British biological weapons expert David Kelly.[47] The Iraqi military settled on the American Type Culture Collection strain 14578 as the exclusive strain for use as a biological weapon, according to Charles Duelfer.
...
The report then detailed 70 shipments (including anthrax) from the United States to Iraqi government agencies over three years, concluding "It was later learned that these microorganisms exported by the United States were identical to those the UN inspectors found and recovered from the Iraqi biological warfare program."[50]
en.m.wikipedia.org
I completely agree with you selling a non-military helicopter isn't selling a weapon. Anthrax though? Other chem and biological? Maybe other things were dual use, but anthrax? We could sell vaccines, selling live anthrax seems far less dual use.
And we gave them military intelligence on using banned weapons:
The U.S. knew Hussein was launching some of the worst chemical attacks in history -- and still gave him a hand.
foreignpolicy.com