The Germans were the first to use Chlorine as a chemical weapon in 1915 at Ypres. Wikipedia gives a fairly reliable account:

Chlorine was inefficient as a weapon, from a purely technical standpoint. It produced a visible greenish cloud and strong odor, making it easy to detect. It was water-soluble, so the simple expedient of covering the mouth and nose with a damp cloth was effective at reducing the effect of the gas.

Chlorine required a concentration of 1,000 parts per million to be fatal, destroying tissue in the lungs. Despite its limitations, however, chlorine was an effective terror weapon–the sight of an oncoming cloud of the gas was a continual source of dread for the infantry.

The terrorists have proven that they will use any weapon at their disposal to terrorize Iraqi civilians, including chlorine.

Of course, we already knew that Al Qaeda had an interest in chemical weapons. Who (besides Democrats) can forget the videos of dogs dying in hideous experiments conducted in Al Qaeda’s refuge in Afghanistan? CNN reported:

Al Qaeda documents examined by CNN last fall in the bombed out ruins of the Darunta camp showed chemical formulas for sarin. Other documents connect the Darunta camp, a series of mud and stone buildings, to chemical testing.

Now we know that Muslim terrorists will use chemical weapons against anyone, including Muslims of a different sect.

The conventional wisdom is that Saddam did not have weapons of mass destruction. The truth is that the UN weapons inspection did not receive proof that Saddam destroyed his known WMD stocks. If any remain in Iraq, then God help the Iraqis if the terrorists get access to them. Chlorine is bad but sarin is really evil.