‘It stays in the body indefinitely’

A co-developer of the Novichok nerve agent on whether the poison could have killed Alexey Navalny

In August 2020, agents from Russia’s Federal Security Service (FSB) tried to murder opposition leader Alexey Navalny using the chemical nerve agent Novichok. Now, in the wake of Navalny’s death on February 16, the Russian government’s refusal to hand over the politician’s body to his family has led to speculation by journalists (including Christo Grozev) that the FSB could have killed Navalny by poisoning him with Novichok once again. In a video statement published on Monday, Navalny’s widow, Yulia Navalnaya, appeared to endorse this theory. To learn what Novichok’s chemical properties can tell us about the plausibility of this version of events, journalists from the independent outlet Agentstvo spoke to Vil Mirzayanov, one of the scientists who developed the poison. (Mirzayanov has lived in the United States since the 1990s.) Meduza has translated the interview into English.

This interview has been edited for clarity.

How long can Novichok and its analogs remain in a person’s body? Is it possible to find traces of it a month after the person’s death?

Novichok can remain in small concentrations even a month after a person is poisoned.

Are there ways the authorities could tamper with the body to remove all traces of Novichok?

I don’t think so. The [chemical’s] degradation products will remain forever as there’s no longer any natural discharge of urine or feces. The Novichok itself will also remain [in the body] indefinitely.

In your first response, you said that Novichok will remain in small concentrations after a month, and in your second response, you said that Novichok can remain in the body indefinitely after a person’s death. Do I understand correctly that the concentration of the poison decreases over time but that it is still detectable even months or years after a poisoning occurs?

I’m speaking based on the experience of [Sergey] Skripal’s treatment in the U.K. (Note from Agentstvo: Skripal and his daughter were poisoned with Novichok in Salisbury, England, in 2018.) After their lives were saved by the antidote, the concentration of Novichok in their bodies just wouldn’t go down. The doctors ended up having to do surgery to almost mechanically destroy the Novichok from their livers and other organs. Not what I expected. Evidently, the Novichok molecules form a bond with the organs and acquire protective shells that then hinder degassing. That’s why I suspect Novichok can persist indefinitely at some concentration level. As for how long, we don’t know yet. Perhaps the British know.

Russia’s Federal Penitentiary Service said that before Navalny died, he started feeling ill and lost consciousness almost immediately. However, Navalny’s mother and lawyers were told that he died of ‘sudden death syndrome,’ which suggests, according to his former doctor, that his heart stopped beating before he even had time to feel ill. Do either of these descriptions fit with the symptoms of Novichok poisoning? If so, how high might the dose have been?

A large concentration can cause instant cardiac arrest. That’s something we know.

Could the body of somebody who was poisoned pose a danger to others? If so, for how long?

Of course. The body of a poisoned person will be dangerous to people without protective equipment. If it’s true that he was poisoned, it’s unlikely they’ll hand over his body to his mother.