Since the start of the social movement in France, concerned testimonies have multiplied around the health effects of tear gas. “First time in my life that I had to type ‘lacry gas breastfeeding’ into my search engine when returning from a demonstration,” Marine Tondelier wrote on X, the day after the demonstration on Saturday October 31.
Deploring the lack of scientific studies on the effects of exposure to tear gas, the environmentalist candidate in the presidential election asked "the government to commission a scientific study to assess the dangerousness of tear gas and their impact on our health". Before her, the Lacrymos de sang collective collected in October more than 10,000 testimonies from menstruating people who reported effects on their cycle after exposure to tear gas.
In this wake, several women testified to franceinfo at the end of October about late periods and unusual pain, after being exposed during demonstrations. Asked about this on Monday during a hearing on the 2027 budget, Laurent Nuñez replied that he was "not aware of the harmful nature of tear gas, which is the basic intermediate weapon". “So, as a precautionary principle, I will not suspend the use of tear gas,” added the Minister of the Interior.
Pain and irritation
Concerns are not only about the potential effects of these gases on the menstrual cycle. On October 17, a demonstrator died near the Parisian procession. Christophe M.'s family has filed a complaint in which they request that additional analyzes of his autopsy "focus on the possible effects of tear gas on (his) condition", announced his lawyer on X, October 28. However, there is nothing at this stage to establish a link between possible exposure to tear gas and his death.
The immediate effects of exposure to tear gas on humans are documented by several scientific studies, but research remains largely insufficient. 2-chlorobenzylidene malononitrile (or CS gas), the chemical substance in this weapon, is used "to scare away exposed people, by activating a pain reaction, particularly in the respiratory tract and eyes", recalls toxicologist Fabrizio Pariselli, director of the chemical risk prevention unit at the CNRS.
This product also has an irritant effect. It manifests itself on the eyes, skin and respiratory tract, according to the toxicological sheet of the National Institute for Research and Safety (INRS). Digestive disorders and headaches can sometimes also be experienced, specifies the INRS. If these symptoms decrease "in a few hours", "more prolonged effects on the skin and the eye are not impossible", explains the institute. “At the respiratory level, the irritant effects can last for several days, even several weeks,” adds Fabrizio Pariselli.
Few recent studies
The harmful effects on health after exposure to tear gas depend in particular on the quantity and duration of exposure, explains the British health safety agency. "Prolonged exposure to large quantities of CS gas ... in a confined space can result in lung damage. Physical injury to the eyes may occur if CS gas is sprayed directly at very close range." If symptoms disappear quickly after exposure, “long-term health effects are unlikely,” writes the American public health agency (CDC).
Few recent studies, however, have focused on long-term effects. A gap highlighted by a “systematic review of injuries and deaths caused by tear gas and pepper sprays”, published in 2017 in the scientific journal BMC Public Health. This synthesis of 31 studies carried out between 1990 and 2015 in 11 different countries establishes that “chemical irritants can cause serious injury, permanent disability and, in rare cases, death”.
In addition to the numerous traumatic injuries caused by tear gas projectiles launched by law enforcement, persistent psychiatric symptoms, respiratory disorders and dermatological conditions have also been noted. These effects were probably "underestimated", due to "the absence of systematic reporting obligations for deaths and injuries occurring in the context of crowd control operations", the authors point out.
Certain “more vulnerable” populations
Scientists also warn about the indiscriminate use of this weapon. “Chemical irritants (...) can affect not only the intended targets, but also peaceful demonstrators (...) as well as the police themselves,” it is underlined. “Injuries to children and the elderly” were noted in particular. These populations, as well as people suffering from chronic illnesses, are “more vulnerable” to exposure to chemical toxicity, it is recalled.
Another study, published in 2020 by the Toxicology-Chemistry Association of Paris, underlines that “at more or less high doses, CS gas causes an irritant effect, which can lead to damage likely to become irreversible in the eyes, skin, lungs and [digestive tract]”. This report also hypothesizes a link between menstrual cycle disorders and exposure to tear gas. But the causal link remains to be demonstrated. Released in pre-publication form, this study has not been peer-reviewed, a process that allows research to be scientifically validated.
Another American study, published in 2023 in the journal Frontiers in Epidemiology, focuses on the gynecological and obstetrical consequences of the use of tear gas by law enforcement during the Black Lives Matters movement that occurred between 2020 and 2021 in the United States. The survey, conducted online among 1,276 menstruating people exposed to these chemicals, suggests a link between exposure and adverse effects on reproductive health.
Menstruating people report an effect on their cycle
Uterine cramps, early or delayed menstrual bleeding, breast tenderness: 83% of people who responded reported at least one adverse effect following exposure. Furthermore, among a small subgroup of 19 people who were pregnant at the time of exposure, ten reported a subsequent miscarriage. However, this study was based on self-assessment, making it largely imperfect.
The authors therefore warn of the urgency of carrying out "a more in-depth investigation into the safety of these products and their impacts on individual and collective health (...) given the widespread use of these chemical agents and their potential for damage to reproductive health".
“Hypotheses on the mechanism of action of this product exist”, but the state of research does not allow us to say whether tear gas alone is responsible for these symptoms, recalls toxicologist Fabrizio Pariselli. “It is not because we have been exposed to a product and feel an effect that it is linked to the product. Other personal or environmental factors may come into play. We must be able to identify them before defining a cause and effect.”
The General Directorate of Health “has not been contacted at this stage”
In order to establish this, it would be necessary to carry out “an epidemiological or mechanistic study in animals”, he believes. But "as long as the public authorities do not tackle this problem, we will not be able to impose tests on manufacturers who put this type of substance on the market", regrets this CNRS research director. When contacted, neither Inserm nor Anses are currently carrying out studies on this subject.
For its part, the Ministry of the Interior told franceinfo that it had “conducted several studies between 2021 and 2022 to assess individual exposure to tear gas, particularly repeatedly for personnel of the internal security forces”. According to the ministry, which did not provide the results of these studies, “during the tests, the short-term limit values over 15 minutes were not reached”. “Usually, these signs regress within a few hours; however, more prolonged effects on the skin and the eye (punctuated keratitis) are not impossible,” the same source admits. Punctate keratitis is an inflammation of the cornea that heals completely in most cases.
The General Directorate of Health (DGS), attached to the ministry, “has not been informed of this question at this stage and does not have specific data on this subject”, she also informed franceinfo. According to the DGS, "the available scientific data do not allow the establishment of a causal link between exposure to tear agents and disruptions of the menstrual cycle. The possible gynecological and endocrine effects of these substances remain insufficiently documented." The DGS nevertheless claims to remain vigilant “to any signal that could be brought to (its) attention”.
