Alex Tylecote kindly shared this surreal bit of research on the Cairo Scholars (CS) listserv.

There has been a lot of discussion about the use of tear gas against the protesters and on its legality according to international treaties and further, the signing of a petition against its use.
I looked carefully at the Paris Convention and at previous conventions. The 1972 Biological and Toxin Weapons Convention (BWC) banned CR gas for use in military operations, but the use of the gas in internal matters is not prohibited.

On the issue of CS gas, the 1997 Chemical Weapons Convention (which Egypt was not actually a signatory to) prohibited the use of the gas for use during military operations, but again not for domestic use, and thus whether Egypt was a signatory to the treaty is irrelevant in this case.

I hope this clears up a few issues for everybody.

So apparently it is not prohibited for use on unarmed civilians, though it is illegal for use on enemies in combat?! That will make for an interesting war crimes trial if it ever happens.

As you can imagine this sparked much discussion on the listserv, with various human rights conventions being cited etc.  It seems a matter of simple logic though.  Plus, the stuff is being used in inhuman amounts. You can get a mouthful of it – enough to make your eyes and throat burn – just driving slowly on the 6 Oct bridge behind the Egyptian Museum, like a kilometer from Mohamed Mahmoud Street.  (Unbelievable to see people going about their daily business under the flyover: filling microbuses with passengers! Selling vegetables!!)  People in Garden City (where I haven’t been) have reported gas reaching their apartments. Here in Dokki, miles from everything, there is a weird heavy haze that could be normal pollution… or not… at this distance it is hard to separate sensation from apprehension.

For details on the gas and more you can read Amnesty International’s report on the SCAF and Ministry of Interior abuses.  The Arabist’s summary of the gas issue, which says basically what I said but with more details and personal experience, is here.