http://en.wikipedia.org/wiki/U.S._support_for_Iraq_during_the_Iran-Iraq_war
After the Iranian Revolution, enmity between Iran and the U.S. ran high. Realpolitikers in Washington concluded that Saddam was the "lesser of the two evils", support for Iraq gradually became the order of the day.
"In June, 1982, President Reagan decided that the United States could not afford to allow Iraq to lose the war to Iran. President Reagan decided that the United States would do whatever was necessary and legal to prevent Iraq from losing the war with Iran. President Reagan formalized this policy by issuing a National Security Decision Directive ("NSDD") to this effect in June, 1982," said the "Teicher Affidavit," submitted on 31 January 1995 by former NSC official Howard Teicher to the U.S. District Court, Southern District of Florida.[3]
According to retired Colonel Walter Lang, senior defense intelligence officer for the United States Defense Intelligence Agency at the time, "the use of gas on the battlefield by the Iraqis was not a matter of deep strategic concern" to Reagan and his aides, because they "were desperate to make sure that Iraq did not lose." He claimed that the Defense Intelligence Agency "would have never accepted the use of chemical weapons against civilians, but the use against military objectives was seen as inevitable in the Iraqi struggle for survival"[4], however, despite this allegation,
Reagan’s administration did not stop aiding Iraq after receiving reports affirming the use of poison gas on Kurdish civilians.[5][6][7]
By contrast, Alcolac International, for example, a Maryland company, transported thiodiglycol, a mustard gas precursor, to Iraq. Alcolac was small and was successfully prosecuted for its violations of export control law. The firm pleaded guilty in 1989. A full list of American companies and their involvements in Iraq was provided by The LA Weekly in May 2003. [13]
There's more details in the rest of the article. You can read them when you grow up and start making ad hominem attacks. I won't hold my breath to wait for Super Moderator to attack someone for going against the rules.