Britain to Scrutinize Suspicious Deaths

LONDON — For nearly three decades, since a Soviet whistleblower told the world of its existence, the nerve agent Novichok has scared U.S. weapons experts. The Pentagon sent teams to destroy abandoned laboratories that once produced the chemical, believed to be orders of magnitude more lethal than sarin or VX.

There was no sign of it ever being used. Until last week.

Now, Britons are taking in the disquieting information that a Novichok nerve agent, a weapon invented for use against NATO troops, was released in the quiet town of Salisbury, its target a former Russian spy named Sergei V. Skripal. Skripal and his daughter, Yulia, collapsed onto a bench in a catatonic state March 4 and remain hospitalized in critical condition.

Britain’s Home Ministry on Tuesday indicated that it viewed state-sponsored violence by Moscow as a larger problem, announcing that it would scrutinize a series of suspicious deaths of Russians on British soil. Home Minister Amber Rudd said the police and MI5, Britain’s domestic security agency, would review 14 cases cataloged last year in an investigation by BuzzFeed. The British police also announced an investigation into the death Monday of Nikolai Glushkov, a close associate of one of Putin’s most prominent foes.

In interviews, chemical weapons experts said it was possible that Novichok nerve agents had been used before on Kremlin targets in Britain but had escaped detection.

Exposure, either by inhalation or through the skin, leads to muscle spasms, secretion of fluid into the lungs and organ failure, sometimes accompanied by foaming at the mouth. But if the victim has already died, experts said, the police could easily mistake the cause of death for a simple heart attack.

“It’s entirely likely that we have seen someone expire from this and not realized it,” said Daniel M. Gerstein, a former senior official at the U.S. Department of Homeland Security who is now at the RAND Corp. “We realized in this case because they were found unresponsive on a park bench. Had it been a higher dose, maybe they would have died and we would have thought it was natural causes.”

The Russian foreign minister, Sergey V. Lavrov, said Tuesday that his country had nothing to do with Skripal’s poisoning, dismissing Britain’s allegation that Moscow was to blame as “nonsense.”

Though U.S. laboratories stopped producing nerve agents around 1970, after the production of so-called third-generation nerve agents like sarin and VX, Soviet scientists continued their work for two decades, producing a “fourth generation.”

The Novichok nerve agents came in solid form, like a powder or thick paste, and would not register on the chemical detector paper that NATO troops used.

For those who somehow survive exposure, their problems are far from over.

“Antidotes exist, but what does antidote mean?” said Vil Mirzayanov, a scientist who helped develop the agent and later immigrated to the United States, in comments to Sky News on Tuesday. “You’re saving a person who has been exposed to this gas — but temporarily, not to die this time. But he will be an invalid for the rest of his life.” Andrew C. Weber, a former assistant secretary of defense for nuclear, chemical and biological defense programs, recalls picking his way through a secret, abandoned Soviet research facility in Nukus, Uzbekistan, which the United States was asked to helped destroy in the early 2000s.

Entering a basement room, Weber saw a disturbing sight: “dozens and dozens of restraining devices” used to immobilize dogs while their skin was exposed to Novichok agents in the form of a powder or paste. He said that he believed each test involved 50 to 100 dogs, and that at least 1,000 dogs had been killed at the facility.

The Pentagon, Weber said, “devoted a lot of resources to improving our protection, detection and countermeasures against it.” But it did not anticipate its use in an assassination, he said, in part because it was so easily traced to Russia.

“It’s obviously tightly controlled by the Russian government,” he said. “It’s implausible to me — possible, but not probable — that this chemical weapon would have been diverted from a Russian facility. It would be well guarded.”

Dan Kaszeta, a chemical weapons specialist who once served as an adviser to the Secret Service, said the nerve agents were “so shrouded in mystery that I don’t know how many chemical compounds are in the Novichok family.”

In Salisbury, where Skripal and his daughter were stricken, residents described mounting anxiety Tuesday as they learned more about the nerve agent. The authorities reassured residents that there was no significant health risk. But they ratcheted up their precautions as the days went on, finally advising people who had been near the victims to wash or wipe everything they were wearing or carrying at the time.

Kaszeta, who now heads a British-based security firm, said the nerve agent could have been transported in a glass jar and spread on Skripal’s steering wheel or on items he handled at a restaurant. The agent then could be transferred to anything Skripal touched for the next two hours, he said. While the chemical would take effect “almost instantaneously” if inhaled, Kaszeta said, it would work much more slowly, perhaps over a matter of hours, if absorbed through the skin. The agent is activated when it comes in contact with water and would be absorbed through the pores, slowed down by subcutaneous fat, Kaszeta said.

At first the effect would be felt locally, around the point of exposure.

Once the chemical entered the bloodstream, it would cause the victim’s muscles to go into spasms, pupils to shrink to pinpoints, and breathing to become very labored, said Alastair Hay, an emeritus professor of toxicology at the University of Leeds. At this point, the victim’s life could be saved only by the administration of atropine, which counteracts the agent and allows the body to metabolize it.

The attack on Skripal and his daughter occurred a short drive from Porton Down, Britain’s premier chemical weapons laboratory, which went to work isolating the agent from blood samples, breaking it into fragments and examining it through a mass spectrometer. Researchers would have initially looked for more common chemical agents, like sarin, and then proceeded through a long series of more obscure ones until they found a match, Hay said.

“When they get an unknown chemical, they will compare it with the information that’s in the library and, bingo, you’ve got all your strawberries lined up,” he said. Given how lethal the agent is, Kaszeta said, it seems probable that the two victims survived by happenstance.

“There are a few ways this could play out, and one is that something got screwed up in the delivery,” he said. “The other is that he washed his hands and got most of it off. The third is that this dosage was sublethal, just to send a message. It could have been the horse head in the bed.”