Well, Teribus, it depends on what you mean by "proof." The article does say:   
"The administrations of Ronald Reagan and George H.W. Bush authorized the sale to Iraq of numerous items that had both military and civilian applications, including poisonous chemicals and deadly biological viruses, such as anthrax and bubonic plague."

Most of us have enough faith in a major unaffiliated newspaper like the Post to assume it wouldn't make that up out of whole cloth. That's not proof sufficient to hold up in court, but it's about as good as anything you are ever going to see in this part of the Forum. Maybe you can rebut it?