Two more people have apparently been poisoned by novichok, the powerful nerve agent used to poison former Russian spy Sergei Skripal and his daughter Yulia in the English town of Salisbury in March.
Skripal, 67, and his 33-year-old daughter spent weeks in Salisbury District Hospital after they were found slumped on a bench in the town centre on March 4. Now, exactly three months later, a second couple in the area has been taken into intensive care with symptoms of nerve agent poisoning.
The British government, which blames Russia for the Skripal poisoning, is working under the assumption that the couple’s exposure is a consequence of that attack. Interior minister Sajid Javid told parliament on Thursday that “it is now time that the Russian state comes forward and explains exactly what has gone on.”
Here’s what to know:
Who are the victims?
Dawn Sturgess and Charlie Rowley, a couple in their 40s, who were taken to hospital on Saturday after falling ill at their home in Amesbury, Wiltshire, just eight miles north of Salisbury. Police initially believed the pair had taken drugs, but have now confirmed they were exposed to novichok.
Is there evidence the Wiltshire couple are or were spies?
No. The police said there was “nothing in their background” to suggest they had been deliberately targeted.
How did they come into contact with novichok then?
Authorities are unsure about where and when the couple were exposed to the nerve agent, but believe their illness may be collateral damage from the Skripal poisoning. They were last seen in public at a family fun day at the Amesbury Baptist Centre on Saturday afternoon. None of the other 200 people present have reported any symptoms.
What exactly is novichok?
Novichok, which means “newcomer” in Russian, is a form of nerve agent developed in the Soviet Union in the 1970s. Scientists were trying to create a weapon more powerful and harder to detect than existing chemical weapons. It was also designed to be exempt from the Chemical Weapons Treaty, because it has a different chemical structure than the nerve agents covered by that agreement.
“It really hasn’t been seen ‘in the wild’, as it were, previously,” Andrea Sella, a professor in Chemistry at University College London. “But novichok works similarly to other nerve agents. It effectively shuts down all nervous communication. Typically people die of asphyxiation. It starts with the eyes, people have difficulty seeing and pinpoint pupils. Then breathing becomes laboured and people start salivating and then foaming at the mouth. And there will be severe pain. It’s a really unpleasant way to die.”
Is it always lethal?
How quickly a nerve agent kills someone depends on how it is delivered and how much. “It’s very different to ingest it or inhale it than have it come through the skin. Skin is pretty inefficient way to deliver something,” says Sella. “The assumption when people hear about a nerve agent or chemical weapon is that you can’t treat it. But theses people were picked up and hospitalised very quickly, receiving very intensive care. It’s a whole different ballgame to what happens in a chemical attack in a town in Syria, for example.”
How were the Skripals poisoned?
Investigators found novichok had been smeared on the handle of their front door. Russia has denied any involvement in the poisoning, though on July 4 the BBC reported that the pair had been under Russian surveillance for months before their poisoning.
How are the authorities responding?
Wiltshire Police Chief Constable Kier Pritchard called the event a “major incident” and said police were stepping up their presence in both Amesbury and Salisbury. He assured the local community that the risk of poisoning was still extremely low. But the National Health Service advised people who had been to any of the five known locations Rowley and Sturgess had visited in the 24 hours before falling ill to take “highly precautionary measures”, including washing clothes immediately and wiping off items like phones.
Neil Basu, Britain’s top counter-terrorism officer, said about 100 detectives from the Counter Terrorism Policing Network are investigating whether or not the novichok came from the same bath that poisoned the Skripals.
Sella says that if authorities can find the source of the Rowley and Sturgess’ posioning it will be “a forensic goldmine”. “They’ll be able to find out what other things were in the package, which will give more certainty about the modus operandi of these people, how they put it together and what they wanted to do,” he says. “Then we’ll narrow down who they are.”
Could more people be exposed?
It’s impossible to say if there could be more poisonings linked to novichok, though experts say the risk to individuals is extremely low.
“One important issue is that we don’t have an answer for how long novichok can be potent,” says Sella. It’s not like radioactivity, where there’s a clock ticking. We know these weapons were designed to be more persistent. Sarin, for example, falls apart quickly with moisture. But novichok was designed not to decompose. If it’s protected, in a container, it may last a long time. And it doesn’t evaporate – though that means there isn’t a risk from inhalation. There is a risk, though very, very small, that someone might stumble across this substance and be exposed.”
Why do the British think Russia is involved?
Russia is thought to be the only government with the capability to produce novichok, though they have denied ever developing it. British Security Minister Ben Wallace told the BBC, “Based on the evidence we had at the time of the Skripal attack, the knowledge they [Russia] had developed novichok, they had explored assassination programmes in the past, they had motive, form and stated policy, we would still assert to a very high assurance that the Russian state was behind the original attack.”
Speaking to Parliament on Thursday, the British Home Secretary (interior minister) Sajid Javid called on Russia to explain how the two British citizens came into contact with the nerve agent.
“It is now time that the Russian state comes forward and explains exactly what has gone on,” he said. “We will stand up to the actions that threaten our security and the security of our partners. It is unacceptable for our people to be either deliberate or accidental targets, or for our streets, our parks, our towns to be dumping grounds for poison.”
A tweet sent out by the Russian embassy in the Netherlands scoffed at the idea that the country would deliberately poison another couple while the Kremlin is enjoying the international prestige of the country hosting the FIFA World Cup.
What are the international implications?
The new illnesses will give the U.K. more ground to criticize Russia’s use of nerve agents as reckless. “That is part of the anger I feel at the Russian state,” Wallace said. “They chose to use a very, very toxic, highly dangerous weapon. Novichok in the smallest form can injure thousands of people.” Major allies, including the U.S., backed the U.K. in blaming Russia for the Skripal poisoning and condemning its use of chemical weapons at the U.N. Security Council.
Yet the timing of the incident could prove awkward for President Trump. NATO leaders will meet in Brussels on July 11 and 12 to discuss security threats including Russian aggression, while Trump is due to visit the U.K. on July 13 and then have a summit with Vladimir Putin on July 16. Britain and its allies will pay close attention to how critical the president is willing to be of Putin.
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Write to Ciara Nugent at ciara.nugent@time.com