As nationwide protests sparked by the death of George Floyd enter their fourth week, the American Thoracic Society is calling for a moratorium on the use of tear gas and other chemical agents to control demonstrators.
On Thursday, ATS officials issued a statement asking law enforcement groups to stop using tear gas agents such as 2-chlorobenzalmalononitrile (CS) and highly concentrated oleoresin capsicum (OC) pepper oil due to concerns about long-term lung injury.
Concerns about the use of these agents on the spread and severity of COVID-19 were a factor in the move, said ATS President Juan Celedon, MD, in the statement.
“The use of chemical crowd control agents is outlawed in the time of war. They cause significant short-term and long-term respiratory health injury and likely propagate the spread of viral illnesses, including COVID-19,” Celedon said.
“Based on the lack of crucial research, the escalation of tear gas use by law enforcement, and the likelihood of compromising lung health and promoting the spread of COVID-19, the American Thoracic Society calls for a moratorium of CS tear gas and OC pepper weapons use,” he added.
The statement was issued on the same day President Trump — speaking at a roundtable discussion on policing and race — praised the use of tear gas and other aggressive tactics against demonstrators in Minneapolis early in the protests, calling it a “beautiful scene.”
Sven-Eric Jordt, PhD, of Duke University School of Medicine, Durham, North Carolina, has spent years researching the impact of chemical exposures — including tear gas — on the lungs.
He told MedPage Today that a study in military recruits linked tear gas exposure to chronic bronchitis, viral respiratory illness, compromised lung function and other acute and possibly chronic lung injuries.
The study, published in the journal Military Medicine in 2014, showed that recruits intentionally exposed to CS during basic training had more than twice the risk for an acute respiratory disease diagnosis after exposure compared to before exposure.
Jordt said recent technical advances in tear gas deployment allow the gas to be dispersed over much greater areas, and the clinical impact of this wider exposure has not been studied.
Likewise, in the U.S. protests and in other parts of the world where tear gas has been widely used to disperse crowds, police tactics have changed in ways that can make exposure more problematic, he added.
“What we are seeing and what we have seen is that police are using massive amounts of these agents,” he said. “In the recent protests in Hong Kong there were days when several thousands of cartridges were used.”
He added that in many recent protests within and outside the United States, tear gas and pepper spray were deployed as a first line measure, rather than a measure of last resort.
“In U.S. cities we have seen episodes where police are boxing in protesters and then using tear gas or pepper spray when the protesters have no way out,” Jordt said.
While there are, as yet, no studies directly examining the impact of tear gas exposure on COVID-19, Jordt and Celedon both said there is cause for concern that exposure may promote SARS-CoV-2 transmission.
Someone exposed to tear gas would be likely to quickly take off protective masks due to contamination, and maintaining a safe distance from other people would probably not be their main concern, Jordt told MedPage Today.
COVID-19 patients also often report loss of sense of smell, which could increase their risk of unknowingly inhaling dangerous levels of tear gas. And tear gas makes people cough, enhancing the virus’s spread if those individuals are currently infected.
“We have seen a dramatic escalation of (tear gas) use that I fear may become normalized,” Jordt said. “We have to reassess the safety of these agents with state-of-the-art toxicological techniques.”