There was evidence of a combination of chemical agents having been used by Iraq against the Kurds in the Halabja chemical attack in 1988 under Saddam Hussein, including VX. Hussein later testified to UNSCOM that Iraq had researched VX, but had failed to weaponize the agent due to production failure. After U.S. and allied forces invaded Iraq, no VX agent or production facilities were found. However, UNSCOM laboratories detected traces of VX on warhead remnants.