CBS News 13th March 2018. The UK Prime Minister - Mrs Theresa May - stated that it was "highly likely" that Russia was responsible for this - see her Statement of Monday 12th March to Parliament.
In this post of 23rd August 2013, chemical weaponry was discussed in connection with the conflict in Syria.
The Chemical Weapons Convention lies at the heart of the position in international law regarding chemical weaponry.
The Convention aims to eliminate an entire category of weapons of mass
destruction by prohibiting the development, production, acquisition,
stockpiling, retention, transfer or use of chemical weapons by States Parties.
States Parties, in turn, must take the steps necessary to enforce that
prohibition in respect of persons (natural or legal) within their
All States Parties have agreed to chemically
disarm by destroying any stockpiles of chemical weapons they may hold
and any facilities which produced them, as well as any chemical weapons
they abandoned on the territory of other States Parties in the past.
States Parties have also agreed to create a verification regime for
certain toxic chemicals and their precursors (listed in Schedules 1, 2
and 3 in the Annex on Chemicals to the CWC) in order to ensure that such chemicals are only used for purposes not prohibited.
unique feature of the CWC is its incorporation of the 'challenge
inspection', whereby any State Party in doubt about another State
Party's compliance can request the Director-General
to send an inspection team. Under the CWC's 'challenge inspection'
procedure, States Parties have committed themselves to the principle of
'any time, anywhere' inspections with no right of refusal.
The Convention has 24 Articles - HERE. Article VIII establishes the Organization for the Prohibition of Chemical Weapons (OPCW).
The Convention (Article I) expressly bans the use of chemical weapons.
Article VII requires State Parties to implement the convention in national law. This was done by the UK with the enactment of the Chemical Weapons Act 1996
Article IX.2 - "Without prejudice to the right of any State Party to request
a challenge inspection, States Parties should, whenever possible, first make
every effort to clarify and resolve, through exchange of information and
consultations among themselves, any matter which may cause doubt about
compliance with this Convention ....."
Article XII - sets out the Measures to Redress a Situation and to Ensure Compliance, including Sanctions.
OPCW 87th Executive Session - Statement by Mr Peter Wilson, UK representative
UK Government - Chemical Weapons Guidance
Chemical Weapons Act 1996
The position under customary international law:
There is some authority that the use of chemical weaponry is unlawful under customary international law.