Video - Obama Says Chlorine isn't 'Historically' a Chemical Weapon, WWI historians might disagree.

The first killing agent employed by the German military in World War One was chlorine.

Chlorine is a powerful irritant that can inflict damage to the eyes, nose, throat and lungs. At high concentrations and prolonged exposure it can cause death by asphyxiation.

German chemical companies BASF, Hoechst and Bayer (which formed the IG Farben conglomerate in 1925) had been producing chlorine as a by-product of their dye manufacturing.

In cooperation with Fritz Haber of the Kaiser Wilhelm Institute for Chemistry in Berlin, they began developing methods of discharging chlorine gas against enemy trenches.

@MFS001 @20committee NIH certainly disagrees http://t.co/lmsntyCbAI

— DC Dude (@DCDude1776) May 15, 2015

Dear President Obama: Chlorine gas *is* a chemical weapon. Signed, 6,000 French soldiers killed & maimed by it at Ypres, 22 April 1915

— John Schindler (@20committee) May 16, 2015