May 20, 2019

Late-Breaking Session Addresses 2018 Nerve-Agent Attack

By Ed Rutkowski

Minneapolis Convention Center (May 20, 2019)—Around noon on Sunday, March 4, 2018, Sergei Skirpal and his daughter Yulia left Sergei’s home in Salisbury, England, ate lunch at a restaurant, headed to a nearby bar, then took a walk. At 4:15 they were found slumped on a park bench, vomiting and suffering from seizures. When emergency responders arrived a little after 4:30, they noted the Skirpals’ pinpoint pupils and assumed they were suffering from an opioid overdose. The medics administered naloxone to reverse the overdose and diazepam for the seizures, but these had little effect. The Skirpals arrived at the hospital at 5:15. It wasn’t until the next day that doctors began to suspect that the Skirpals were suffering from exposure to a nerve agent.

Later, a massive investigation undertaken by the U.K. government uncovered that the Skirpals had been deliberately poisoned. Operatives working for the Russian government had sprayed a doorknob at Sergei's house with what is known as a fourth-generation nerve agent, or FGA, an act of retribution against Sergei Skirpal, a Russian double agent.

Following the Salisbury incident, the White House National Security Council convened a working group to develop resources for emergency responders in case a similar exposure occurs in the United States. Two industrial hygienists involved with the working group, John Koerner of the Department of Health and Human Services and Jennifer Hornsby-Myers of NIOSH, addressed attendees at AIHce EXP 2019 today to share what they had learned about the dangers of FGAs and the ways emergency responders can protect themselves if they encounter these highly toxic substances.

In the realm of nerve agents, FGAs are “kind of a unique animal,” Koerner said, distinct from highly volatile chemical warfare agents such as sarin and low-volatility agents such as VX. Because they evaporate quickly, sarin and other volatile nerve agents pose an inhalation hazard; symptoms of exposure often appear within minutes, Koerner said. Low-volatility agents present a dermal contact hazard; symptoms can be delayed for hours or days. Developed by the former Soviet Union, FGAs—also known as “novichoks”—are more persistent than other nerve agents and pose several unique challenges, Koerner explained.

Detection of FGAs is particularly problematic. “Time is important, patience is important,” Hornsby-Myers said. “What it looks like at one minute is not what it looks like at ten minutes.” She emphasized that a failure to detect FGA doesn’t mean it isn’t present. In cases where signs and symptoms suggest the presence of FGA but instruments don’t detect it, “go with signs and symptoms,” Hornsby-Myers said.

All nerve agents inhibit the enzyme Acetylcholinesterase, or AHcE, which breaks down the neurotransmitter acetylcholine, Koerner said. With AHcE inhibited, acetylcholine builds up and eventually causes hyperactivity of the target organs, a condition known as cholinergic crisis.

During the Salisbury incident, doctors didn’t suspect the Skirpals were in cholinergic crisis until a day had passed. The hospital sent out samples to a lab to confirm the presence of a nerve agent, but due to a logistics error, the samples weren’t analyzed for another day. By the time the doctors’ suspicions were confirmed, hospital staff had been handling the patients, without decontamination, for three days.

The Skirpals were placed into induced comas and treated with enough atropine that the hospital had to order more, Koerner said. Around day nine, tests showed that the Skirpals’ AHcE activity was still zero. Eventually the doctors deduced that the agent was still present on the Skirpals’ hands, delivering a continuous dose. For the next two days, staff repeatedly treated the Skirpals with the Reactive Skin Decontamination Lotion Kit, or RDSL, which is used to neutralize chemical warfare agents. The Skirpals’ condition gradually improved, and they were discharged approximately 70 days after exposure.

Within a year of the Salisbury incident, the U.S. working group had produced three documents to help emergency responders recognize and address possible FGA exposure. “Fourth Generation Agents: Safety Awareness for First On-Scene Responders” is a one-page PDF that summarizes what happened in Salisbury and offers information on how emergency responders can protect themselves and what they need to do to decontaminate. The other documents are medical management guidelines (PDF) and a reference guide (PDF) that resembles a Safety Data Sheet.

Both Hornsby-Myers and Koerner repeatedly emphasized the need for emergency responders to follow proper protocols when responding to incidents with unknown chemical hazards, such as wearing appropriate PPE. “Part of the job here is to help responders understand they can protect themselves and help the public,” Hornsby-Myers said. “It is extremely important to have strict adherence to donning and doffing. Be mindful, and follow the [guidance] that is already out there.”

Ed Rutkowski is editor in chief of The Synergist.

View more Synergist coverage of the conference on the AIHce Daily page.