Tear Gas is a Chemical Weapon, ain't that Ironic

Whether this meme depicts a US warship or even US protesters is irrelevant. The message and irony were obvious.

However some were out claiming that Pepper spray or CS gas is not a chemical weapon. 

Well sorry to disappoint you folks but they are chemical weapons and they are banned for use in warfare under article 1.5 of the Chemical Weapons Convention.

But there are no restrictions to their domestic use as a “riot control agent.”

That's whats Ironic

Pepper spray is banned for use in war by Article I.5 of the Chemical Weapons Convention, which bans the use of all riot control agents in warfare whether lethal or less-than-lethal.

Article I. General Obligations
1. Each State Party to this Convention undertakes never under any circumstances:
(a) To develop, produce, otherwise acquire, stockpile or retain chemical weapons, or transfer, directly or indirectly, chemical weapons to anyone;
(b) To use chemical weapons;
(c) To engage in any military preparations to use chemical weapons;
(d) To assist, encourage or induce, in any way, anyone to engage in any activity prohibited to a State Party under this Convention.
2. Each State Party undertakes to destroy chemical weapons it owns or possesses, or that are located in any place under its jurisdiction or control, in accordance with the provisions of this Convention.
3. Each State Party undertakes to destroy all chemical weapons it abandoned on the territory of another State Party, in accordance with the provisions of this Convention.
4. Each State Party undertakes to destroy any chemical weapons production facilities it owns or possesses, or that are located in any place under its jurisdiction or control, in accordance with the provisions of this Convention.
5. Each State Party undertakes not to use riot control agents as a method of warfare.

Riot control agents including tear gas and pepper spray are banned in international warfare under both the 1925 Geneva Protocol and the Chemical Weapons Convention (CWC). The CWC defines chemical weapons as “munitions and devices that are designed to cause death or other harm through toxic chemicals” that lead to “death, temporary incapacitation or permanent harm to humans or animals.”  While tear gas and pepper spray, under international law, are banned as a “method of warfare”, there are no restrictions to their domestic use as a “riot control agent.” According to the CWC, “riot control agents” are any chemicals which are not specifically listed in their list of prohibited chemicals and that can cause in humans rapid “sensory irritation or disabling physical effects which disappear within a short time following termination of exposure.”  Under Article II Section 9 of the CWC, the use of such chemicals for “law enforcement including domestic riot control purposes” is not prohibited under the Convention.

LINKS
https://www.opcw.org/chemical-weapons-convention/articles/article-i-general-obligations
https://en.wikipedia.org/wiki/Pepper_spray
http://teargasresearch.com/?page_id=16