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Analytical Chemistry

Nerve agent attack on spy used ‘Novichok’ poison

Chemical weapon used in U.K. assassination attempt was developed by Soviet Union during Cold War

by Mark Peplow, special to C&EN
March 13, 2018 | A version of this story appeared in Volume 96, Issue 12

La sustancia 33, también conocida como VR, se desarrolló como agente Novichok binario como parte del programa de armas químicas de la URSS. El programa también creó agentes nerviosos como el A-230, el A-232 y el A-234, alguno de los cuales se han convertido en agentes Novichok.
Chemical structures of organophosphorus Novichok agent VR and the organophosphorus nerve agents A-230, A-232, and A-234.
Substance 33, also known as VR, was developed into a binary Novichok agent as part of the U.S.S.R.’s chemical weapons program. The program also created nerve agents such as A-230, A-232 and A-234, some of which became Novichok agents.

Chemical weapons experts have identified the nerve agent used in the attempted murder of a former Russian double agent living in the U.K. It is part of a family of compounds known as Novichok agents that were developed in a Cold War-era weapons program in the former U.S.S.R. Russia now faces questions about its involvement in the attack, and indeed whether it has violated the Chemical Weapons Convention.

The nerve agent was used against Sergei Skripal, previously a Russian military intelligence officer who was convicted of leaking secrets to the U.K. He was released in 2010 and settled in Salisbury, England, where he and his daughter Yulia were poisoned on March 4.

“It is now clear that Mr. Skripal and his daughter were poisoned with a military-grade nerve agent of a type developed by Russia,” U.K. Prime Minister Theresa May said on Monday, March 12, citing work by investigators at the U.K.’s Defence Science & Technology Laboratory at Porton Down. May said that it was “highly likely that Russia was responsible”, although Russia has denied any involvement in the attack.

Novichok agents are organophosphorus compounds, similar to sarin and VX, which inhibit the enzyme acetylcholinesterase and cause a biochemical logjam that cripples the nervous system. Symptoms range from sweating and twitching to seizures and an inability to breathe. The U.K. has not disclosed the specific Novichok agent used against the Skripals.

“The U.S.S.R. is the only country to have developed and produced these [Novichok] agents,” says Jean Pascal Zanders, an independent consultant who was previously a senior research fellow at the European Union Institute for Security Studies. “It’s almost as though the Russians are sending a message to the West that they can reach anywhere, whenever they like.”

The newcomers

Much of what is publicly known about Novichok agents comes from Vil Mirzayanov, an analytical chemist who worked for the State Research Institute of Organic Chemistry and Technology (GosNIIOKhT), a notorious chemical weapons laboratory. Mirzayanov developed methods to detect nerve agents created and tested in the U.S.S.R.’s chemical weapons facilities. His techniques would be used to monitor the environment for any traces of the agents that might reveal the labs’ activities to foreign intelligence services.

In the late 1980s, Mirzayanov’s analytical techniques revealed that nerve agents were befouling the air and water around one of these facilities, posing a major health risk. So he went public, revealing details of the U.S.S.R.’s chemical weapons program to Moscow News in 1992. Officials arrested and imprisoned Mirzayanov, but eventually dropped the case against him. In 1995, he immigrated to the U.S., where he subsequently wrote a book about his experiences, titled “State Secrets: An Insider’s Chronicle of the Russian Chemical Weapons Program.”

Chemical structures of organophosphorus Novichok agent VR and the organophosphorus nerve agents A-230, A-232, and A-234.
Credit: Adam Gerrard/Daily Mirror/Newscom
Firefighters secure a tent over the bench where Skripal and his daughter were found unconscious.

The book documents the U.S.S.R.’s search for new chemical weapons—the “Foliant” program—from the early 1970s until the early 1990s. That program had several goals. It aimed to develop nerve agents that could not be stopped by the chemical protective gear available to NATO soldiers at the time. It also looked for chemical agents that were safer to handle and undetectable in conventional analytical tests. One of the key approaches used to achieve the safety and evasion goals involved so-called binary agents—chemical weapons that could be produced immediately before they were deployed, by combining simple and innocuous precursors. “They would have used precursors more frequently present in the chemical industry,” says Ralf Trapp, a consultant chemist and toxicologist who previously worked for the Organisation for the Prohibition of Chemical Weapons (OPCW).

According to writings by Jonathan B. Tucker, a chemical weapons expert, the first binary formulation developed under Foliant was used to make Substance 33, also known as VR. This compound is very similar to the more widely known VX, differing only in the alkyl substituents on its nitrogen and oxygen atoms. “This weapon was given the code name Novichok,” Tucker wrote in “War of Nerves: Chemical Warfare from World War I to Al-Qaeda.” Novichok is the Russian word for ‘newcomer’.

In “State Secrets,” Mirzayanov tells that the program also developed a range of compounds based on the phosphorus-oxygen-fluorine core of older nerve agents like sarin and soman. By substituting the O-alkyl group in these compounds for an amidine, Foliant scientists created a molecule dubbed A-230. Some five to eight times more poisonous than VX, it was subsequently adopted as a chemical weapon by the Soviet Army. Further variations on this theme produced A-232, which had a similar toxicity to Substance 33 but was much more volatile; and its ethoxy analogue, A-234.

GosNIIOKhT researchers then developed a binary formulation that would produce A-232 (or something very close to it) on demand. This was designated Novichok-5. “Both precursor chemicals had legitimate industrial uses,” Tucker wrote, “so they could be produced at plants ostensibly designed to manufacture agricultural fertilizers or pesticides.” In 1993, Foliant spawned another binary—Novichok-7—that was reportedly just as potent.

Mirzayanov writes that the U.S.S.R. produced a few tons of Novichok-5, and tens of tons of Novichok-7. According to Tucker, the U.S.S.R. carried out open-air tests of Novichok-5 in the early 1990s on the Ustyurt Plateau, a desert area close to the border of present-day Kazakhstan and Uzbekistan. Györgyi Vásárhelyi and László Földi of the National University of Public Servicehave reported that Novichok-5 and -7 act very rapidly, penetrating the skin and respiratory system.

Plausible explanations

Mirzayanov’s account only provides a snapshot of the Foliant program. Indeed, other scientists have proposed many different formulas for Novichok agents, including a series that incorporates a myriad of dihaloformaldoxime groups. Some estimate that over 100 nerve agents were developed under Foliant, although it is unclear how many of them evolved into binary agents.

Novichok agents are not specifically listed in the schedules of the Chemical Weapons Convention (CWC), says Zanders, because “they only became public after the treaty negotiations had been concluded.” But that does not amount to a loophole that would allow their use, because the CWC places a blanket prohibition on the manufacture of any toxic chemical intended to be a weapon. “It covers any toxic chemical, be it past, present, or future,” says Zanders. Russia has been a party to the convention since late 1997, and the Novichok agents “should have been declared to the OPCW, even if they don’t appear in the schedules,” says Zanders.

Prime Minister May has said that there are only two plausible explanations for the attack on the Skripals: “Either this was a direct act by the Russian State against our country, or the Russian government lost control of this potentially catastrophically damaging nerve agent and allowed it to get into the hands of others.” Either of those scenarios would mean that Russia is in breach of the CWC, says Zanders.

May has demanded an explanation from Russia, along with a complete disclosure of the Novichok program to the OPCW. Meanwhile, the executive council of the OPCW is holding a scheduled meeting in The Hague today. Zanders expects that the Novichok attack will be high on the agenda.

CORRECTION: This story was updated on March 15, 2018, to specify when Russia became a party to the Chemical Weapons Convention.

This article has been translated into Spanish by and can be found here.


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