Anybody who told you this or any source you can find is wrong. The U.S. did not supply Iraq with biological weapons. The U.S., along with many other nations, did supply them with biolical materials for research on medical purposes. These sales were aproved by the Center of Disease and Control in Atlanta, not the DOD,CIA etc. In the 1980s, any college profesor had access to the same materials that the nation of Iraq could get.
However, Hussein had no intention of research for medical purposes, and built a weaponizing program instead.