Case Study

The Skripal poisoning:
the Novichok agent

Silvia Fiore

from the Editorial Team

How a deadly nerve agent almost killed former Russian double spy and his daughter

On the 4th of March 2018 the former Russian double spy, Sergei Skripal, and his daughter, Yulia, were poisoned with a nerve agent known as Novichok in the city of Salisbury, UK. The two Russian citizens were found collapsed on a park bench after having lunch in a restaurant close by. Both have successfully recovered from the attack.

This case study will touch key aspects of the Skripal poisoning, from how the chemical agent was allegedly dispersed to what the first response was, as well as what decontamination practices are been carried out. It must be noted, however, that the case is still open and a lot of speculations have been made. Months after the attempted assassination took place, very few details have been released from the investigations and many questions remain unanswered.

Who is responsible for the attack on the Skripals?

As the Russian state has previously produced the weapon, investigators say that it is highly likely that it would still be capable of doing so today. However, how it was administered and who might have done it have not been revealed.

The Novichoks are chemically similar to other nerve agents such as the V series of agents, which includes the VX used in the assassination of North Korean exile Kim Jong-Nam in Kuala Lumpur in 2017. Nevertheless, still little is known about them. Credible open sources report that they were first developed in the 1980s in the Soviet Union. The small amount that we know about these agents is based on reports from Russian chemist Vil Mirzayanov, who exposed the development program in 1991. According to Mr. Mirzayanov, the institute responsible for the development of this ‘fourth generation’ nerve agents is allegedly a branch of the State Institute for Organic Chemistry and Technology, which were developed from the German ‘G series’ and the British ‘V series’ of nerve agents to create a deadlier version. It is highly likely that the Novichoks were developed to prevent detection by the West and to circumvent international chemical weapons controls.

How was the attack executed?

While Novichoks' chemical structures remain unclear, these agents can be made with common chemicals in simple pesticide factories. This makes it more difficult to detect its manufacture and regulate the raw materials used to make it: they are inexpensive, generally readily available, and not banned.

Nerve agents are stable and easily dispersed, highly toxic and have rapid effects both when absorbed through the skin and via respiration. They can take the form of gas, aerosol, or liquid, and enter the body through inhalation, the skin, or the consumption of liquid or food contaminated with them. It is still not clear when or how the Skripals were exposed to the chemicals and how much was administered to them, but there are two most solid theories that have been put forward.

The first is that the nerve agent circulated around in a dust-like powdered form in the Skripals’ car after switching the engine on. Therefore, the main route of exposure is thought to be by inhalation. The days before the attack were extremely cold and the suspects could have banked on the Skripals cranking up the car’s heating. In that case, most of the powder would have blown away but only a tiny amount, around five microns, is required to have a severe effect.

The other theory is that the 50-100g of the agent were put in liquid form on their car’s door handles. In fact, 100g – equivalent to 100ml – is the maximum amount allowed in a carry-on luggage on a flight. Experts suggest that the fact that the Skripals survived the attack is an indication that toxin was supposed to be slow-acting on purpose or to be absorbed through the skin. In fact, a higher dose could have resulted in lethal consequences within minutes.

The route for entering the body influences the symptoms developed and their timing. Generally speaking, the poisoning works faster when the agent is absorbed through the respiratory system than via other routes. This is because the lungs contain numerous blood vessels and the inhaled nerve agent can therefore rapidly diffuse into the blood circulation and thus reach the target organs. If it needs to pass through the skin’s outer layers, the first symptoms will not occur until 20-30 minutes after the initial exposure but may be more rapid if the total dose of nerve agent is high. The toxic effect of nerve agents depends on them becoming bound to an enzyme, acetylcholinesterase, and thereby inhibit this vital enzyme's normal biological activity in the cholinergic nervous system.

How did symptoms from Novichok poisoning manifest?

Novichoks are reported to be 5–8 times more lethal than VX nerve agent and effects are rapid, usually within 30 seconds to 2 minutes. Local effects are thought to be immediate, while systemic effects may be delayed up to 18 hours. The symptoms of exposure to any nerve gas can be initially mundane. Those affected may notice a runny nose, excess salivation and sweating, and contracted pupils. These symptoms quickly escalate, however, to constriction of the chest, difficulties in breathing, nausea and vomiting, and loss of bowel control. This gradual loss of body function continues, culminating in spasm and convulsions, and perhaps coma, before eventual death due to respiratory failure. The effects of exposure last for a significant amount of time, and even those lucky enough to survive do not necessarily do so unscathed but commonly suffer neurological damage.

Sergei and Yulia both collapsed at the same time on a bench outside a shopping center in what is believed to be a delayed reaction to the agent. 38 people in the city may have been exposed to the agent, but most are suffering minor symptoms. However, a highly potent nerve agent would hurt anyone who comes in contact with it. Surprisingly, the BBC reported that a doctor who administered first aid to the collapsed Yulia Skripal for 30 minutes was not affected at all. Another doctor, Steven Davies, head of the emergence room of the Salisbury District Hospital, wrote in a letter the London Times:"... no patients have experienced symptoms of nerve agent poisoning in Salisbury and there have only ever been three patients with significant poisoning."

What first response procedures were carried out?

If someone shows signs of nerve agent poisoning, the first thing to do is to check for decreased acetylcholinesterase activity with blood tests. This reveals if a nerve agent has bound to the enzyme. Although Novichok agents have been specifically designed to be resistant to standard therapy, antidotes do exist for other types of nerve agent and must be given immediately in order to be effective with the Novichoks as well. Antidotes are generally used in combination with other compounds that block acetylcholine receptors, such as chemical atropine and oximes. These compounds can be used to restore the enzyme that helps break down acetylcholine to working order. However, it is unknown how well these antidotes work against Novichok agents specifically.

The Skripals have most likely received the same treatment that is given for other types of nerve agent exposure. This includes atropine to block the effects of acetylcholine, pralidoxime to restore acetylcholinesterase activity, diazepam to stop convulsions, and ventilation to assist breathing.

How is the decontamination been conducted?

Novichoks were also reportedly engineered to be undetectable by standard detection equipment, which challenges further investigation. Five days after the attack, an additional 180 military personnel were deployed to the scene to help police investigate the potential contamination of several sites. This was followed by the removal of the restaurant table where the Skripals ate on the day of attack for examination. Restaurant employees were also advised to wash their uniforms, but not to burn them.

The decontamination work in Salisbury started on the 17th of April and is expected to take some months to complete. Ms. Cunningham, chair of the recovery coordinating group, said that "the clean-up process is effective and going well". In total 9 sites have been identified as requiring specialist decontamination, but there is "no need to take any additional precautions to protect the public from any potential risk". 3 of the sealed places, including an ambulance, have already been handed back and returned to use. Decontamination procedures involved a complex process of testing, the removal of items which could be contaminated and that might harbor residual amounts of the agent, and chemical cleaning and retesting. All waste will be safely removed and incinerated. Each site will not be released until decontamination is complete.

July 19, 2018: Multiple sources state that the investigation team may have identified the suspected perpetrators of the Novichok attack thanks to CCTV footage of the area. The suspects are believed to be Russians. A new inquest is set to open today after the death of Dawn Sturgess, 44. The victim died earlier this month, eight days after coming into contact with the Novichok while her partner, Charlie Rowley, 45, is critically ill. The assumption is that the poison came from the same batch used in the Skripal attempted assassination, but this time the two subjects were exposed to at least 10 times the amount of the chemical agent.