Under Saddam Hussein, Iraq launched a bioweapons program around 1985 but initially lacked the expertise to develop sophisticated arms. By the time of the Gulf War cease-fire in 1991, however, Iraq had weaponized anthrax, botulinum toxin, and aflatoxin, and had several other lethal agents in development. Inspectors from the U.N. Special Commission (UNSCOM) chased down evidence of the program, which Iraq repeatedly denied existed. The UNSCOM team found that Iraq's stockpile included Scud missiles, bombs, and artillery shells loaded to deliver disease.
Iraq was known to have unleashed chemical weapons on Kurdish civilians and Iranian soldiers in the 1980s, and while there was no evidence that the Iraqi state had ever used its biological arsenal, fear of this arsenal remained rampant.
In April 1991 the United Nations Security Council passed Resolution 687, which required Iraq to destroy any chemical, nuclear, and biological weapons. Nonetheless, suspicions that Iraq continued to harbor secret weapons of mass destruction persisted, and these fears led, infamously, to the U.S. invasion of Iraq in 2003.
It is now clear, however, that soon after the passage of Resolution 687, threatened by sanctions, Iraq destroyed the munitions and stockpiles of their bioweapons program as well as destroyed or hid all records of the program.