The possession of chemical weapons is a storyline. It was used in Syria also. The real truth is that Benghazi was a weapons hub where weapons of all types that were leftover in Libya were then transferred to the rebels fighting in Syria (ISIS). We spent all of that time trying to frame Assad for using chemical weapons against the population, but the truth was that chemical weapons were being used by the rebels.
Now the storyline is that ISIS has obtained chemical weapons in Iraq. This claim is pointless as they've had them all along! This picture is being framed with cheap gold plating.