What was the agent used?
An early report that the hospital was dealing with poisoning caused by an opiate such as fentanyl was
most likely based on the initial working diagnosis. Signs of
organophosphate poisoning – constricted pupils, vomiting, reduced
consciousness and reduced breathing – could easily be mistaken for
opiate overdose, usually a more likely diagnosis. OPCW has stated that
the BZ detected by the Swiss Federal Institute for Nuclear, Biological
and Chemical Protection in one of the samples sent by OPCW was not from
Salisbury but was in a control sample.
The Russian ambassador reported that
on 12 March the Foreign Secretary had told him that the nerve agent
used against Mr and Ms Skripal had been identified as A-234. The OPCW report issued on 12 April did
not identify the agent but stated that they had confirmed the
identification made by the UK and that this identification had been
included in the confidential report provided to “States parties”. On 14
April the Russian Foreign Minister stated that A-234 had been reported by
the Swiss Federal Institute for Nuclear, Biological and Chemical
Protection that was one of the four accredited labs used by OPCW to
analyse the Salisbury samples.
Based on public reports, a ChemSpider record for A-234 has
been created which assigns it the IUPAC name ethyl
[(1E)-1-(diethylamino)ethylidene] phosphoramidofluoridate. Its predicted
vapour pressure is very low indicating that it is predicted to be
non-volatile. No information on its stability is available. The OPCW
director Uzumcu stated in a newspaper interview that
the agent “seems to be very persistent,” and “not affected by weather
conditions”. This was confirmed the next day by an OPCW press statement
that: “the chemical substance found was of high purity, persistent and
resistant to weather conditions”. Ian Boyd, the chief scientific adviser
at the Department for Environment, Food and Rural Affairs, was reported to
have stated: “The chemical does not degrade quickly. You can assume it
is not much different now from the day it was distributed”. No
experimental studies of the stability of A-234 have been reported.
