The Iraqis army from 1983 to 1988 used mustard gas, tabun, sarin and possibly other chemical agents against the Iranians. Most notoriously, in 1988, Iraqi aircraft dropped sarin and mustard gas on Iraqi Kurdistan, killing up to 5,000 Iraqi Kurdish civilians.
CIA special adviser Charles A. Duelfer in a detailed 350,000-word document (October 2004) reported "During the early years, Egyptian scientists provided consultation, technology and oversight allowing rapid advances and technological leaps in weaponization". The Egyptians supplied Iraq with 9-foot-long Grad rockets pre-equipped with plastic inserts in the warheads to hold the poisons. In 1983, the Egyptians modified the Iraqis' Grad 122mm multiple-launch rocket system to enable warheads to carry chemical agents. That powerful weapon system can launch 40 rockets with a range of 12 miles.
Iraqi government paid Egypt $12 million for the service. Baghdad used nerve agents to kill thousands of Iranian soldiers and Iranian and Iraqi civilians.
These findings are not surprising considering the integrated financial, technical, and armaments that were provided by many Arab countries to support Arabic Iraq against non-Arab Iranians and Kurds. The war began when Iraq with full encouragement of the President Ronald Regan invaded Iran on September 22, 1980. This war resulted in a death of over 250,000 Iranians and permanent physical and mental injury of several million other Iranians and Kurds. The consequence of this war was devastation for both Iraqi and Iranian people.