British investigators have announced that a "nerve agent" was used in an attempt to murder Russian former spy Sergei Skripal in Salisbury on March 4. But they have not specified what nerve agent was used in the attack.
RFE/RL correspondent Ron Synovitz spoke on March 8 about the case with Alastair Hay, a professor of environmental toxicology at the University of Leeds and a member of the British government's advisory group on chemical warfare agents.
RFE/RL: When you consider all the symptoms reported by witnesses who discovered Sergei Skripal and his daughter incapacitated on a bench in Salisbury, and the fact that a first respondent police officer was also exposed, does this information point specifically to any particular nerve agent?
Alastair Hay: It's a laboratory investigation now that has identified the nerve agent. And it was [Britain's] chemical defense establishment. They are very accomplished. The government has said it is not one of the more common [nerve] agents. So what they're essentially ruling out is sarin and VX. [Nerve agents] that you hear less about in the news are tabun and soman. I think it is, possibly, one of those. It could be cyclosarin. But since they said it's not Sarin, they're probably ruling out the Sarin-like compounds. So [of the five main nerve agents], tabun and soman are the likely candidates. Of course, there are other nerve agents as well. We'll just have to wait and see what the final investigation reports.
RFE/RL: Victims can be exposed to nerve agents through ingestion, or in the case of an aerosol compound, through inhalation or skin contact. Do you think this attack was carried out with a nerve agent in aerosol form?
Hay: At this stage, I don't know. I was considering that it might have been an aerosol delivery because there seems to have been some residual contamination – which is why one police officer became ill. If he came into contact with a contaminated surface, he would have become ill.
RFE/RL: If it was an aerosol delivery, would it have been more likely that they were exposed while they were outside walking rather than inside the restaurant or the pub they'd visited before they became incapacitated?
Hay: More likely, but I have to reserve judgment on that.
RFE/RL: Is it possible that an ordinary chemist could have manufactured such a nerve agent? Or is this more likely a case of the nerve agent being manufactured in a laboratory with military capabilities?
Governments have a fairly good idea of how other governments have produced different agents.
Hay: I think it's more a case in which we are talking about a military capability. If you are a diligent chemist, you will find procedures for making sarin and tabun and various other chemical agents. But there's the complexity in making it and how efficient the reaction is. And, of course, there is the risk of exposure in making something, too.
So containment to make sure that the laboratory person is not exposed is absolutely crucial. So I think, really, what one is looking at here is probably more a military-type manufacture. But again, we just have to wait and see.
RFE/RL: What kind of evidence do British investigators need to determine how and where this nerve agent was manufactured?
Hay: If the forensic people have been able to get environmental samples, then there is a possibility that they may contain either some breakdown products or unreacted reagents in the mixture. This could help to provide a fingerprint on the method of manufacture. Governments have a fairly good idea of how other governments have produced different agents. So that could also give a clue.
You wouldn't get that sort of information from looking at biological samples; that is, blood or urine from the individual [victims], because the contaminants would be there in very small amounts. But environmental samples would provide you the best opportunity of trying to get a decent fingerprint.
RFE/RL: Suspicions have been raised about the possible role of Russia. Are there any other specific lines of inquiry that investigators would be following to determine if there are connections to any state actors?
Hay: Ideally, what they would be looking for is to try to establish that fingerprint by looking at environmental samples to try and get a clue about how it might have been made. If you know the method of manufacture that will give you some clue as to how somebody might have procured something. That would give them a good indication of the possible source.
It's going to be some time before the British government is in a position to say who it suspects.
Then, of course, they will be looking at all the possible contacts of the [victims], where they were, and so on -- who might have met them in the intervening period. The investigation will involve looking at camera footage to try to identify many of the people who were in the area. It will be all of that evidence that they'll have to assess.
In my view, it's much, much too early to point a finger at anybody at this stage. It was obviously an intention to kill at least one of them. I don't know whether the daughter was affected inadvertently. Who did it? We have to wait until there is much more evidence.
RFE/RL: As a field investigator into previous attacks involving chemical agents, what are the hindrances to being able to say for certainty who carried out a nerve agent attack?
Hay: If you've got a smoking gun, it becomes much more difficult to determine whether there are fingerprints on the trigger if somebody has made an attempt to wipe the fingerprints off. It looks like a pretty sophisticated job. So the complications of identifying are magnified and it's going to be some time before the British government is in a position to say who it suspects.
The implication [of possible Russian involvement] was made by our foreign secretary [Boris Johnson]. But I don't think the evidence warrants finger pointing at Russia at this time. The evidence needs to be assessed in a cold and calm way. Then we'll see what it indicates.
RFE/RL: How long do you think it will take before the British government will be in a position to point a finger in this case?
Hay: I think we will be talking about weeks in this instance. What form all of the investigations are going to take and what routes the government is going to pursue, I am unclear. But I would think quite a lot of that evidence would be collected over weeks. Possibly months. But that's unlikely. The government is under pressure here to do something quickly. It will be putting pressure on everybody to try and come up with their evidence promptly so it can be assessed.