Tear gas can kill you, though deaths from the chemical agent alone are rare. The most dangerous scenario is exposure in a confined space, where high concentrations can cause severe chemical burns to the throat and lungs, leading to respiratory failure. The CDC lists “immediate death due to severe chemical burns to the throat and lungs” as a possible outcome of large-dose or prolonged exposure, particularly indoors.
How Tear Gas Affects Your Body
Tear gas is a blanket term for several chemical irritants, with CS gas being the most widely used today. When the particles hit your eyes, skin, and airways, they trigger an intense burning sensation, tearing, coughing, and a feeling of chest tightness. At typical outdoor concentrations, these effects are temporary and resolve within 15 to 30 minutes after you move to fresh air.
The chemical works by reacting with moisture on your skin and in your mucous membranes, essentially attacking the protective lining of your eyes, nose, mouth, and lungs. At low doses, this causes pain and irritation. At high doses, the reaction becomes destructive, burning tissue deep enough to cause lasting damage to the airways.
When Tear Gas Becomes Lethal
The difference between a painful but survivable exposure and a fatal one comes down to two factors: concentration and ventilation. Outdoors, tear gas disperses quickly. Indoors or in any enclosed space, concentrations can build to levels far beyond what the agent was designed to produce. A documented case from Bahrain describes a man who died of respiratory arrest after CS gas was fired directly into his home. The chemical burns to his airways were severe enough to stop his breathing entirely.
No precise lethal dose for CS gas in humans has been established through controlled studies, for obvious ethical reasons. But the CDC is clear that a large enough dose can cause immediate death from airway damage, or respiratory failure that kills over a longer period. These outcomes are most likely when someone cannot escape the gas, whether because they’re trapped indoors, restrained, or in a poorly ventilated area like a vehicle or basement.
Deaths From the Canister Itself
The gas isn’t the only lethal component. Tear gas canisters are heavy metal projectiles, and when fired directly at people rather than lobbed at the ground, they can cause fatal injuries. A study examining penetrating head injuries from tear gas canisters found 10 cases, all in young men aged 14 to 19. Every single one died within one to three days of being hit, a 100% in-hospital mortality rate. Another documented death involved a protester in Nepal killed by traumatic brain injury from a canister impact.
These deaths are distinct from the chemical effects of tear gas, but they’re a real part of the risk profile. Canisters can fracture skulls and penetrate the brain when fired at close range or aimed directly at individuals.
Lasting Lung Damage From Exposure
Even when tear gas doesn’t kill immediately, heavy or repeated exposure can cause chronic respiratory problems that persist for months or years. A study of 93 people exposed to tear gas found measurable declines in lung function that were still present months after exposure stopped. Both smokers and nonsmokers showed obstructive patterns in their breathing tests, meaning their airways had narrowed in a way that limited airflow.
Among people exposed to tear gas on a regular basis (averaging about eight exposures over a lifetime), respiratory complaint rates ranged from 26% to 44%. The types of long-term damage documented in heavily exposed populations include chronic obstructive pulmonary disease (35% of cases in one study), bronchiectasis, or permanent widening and scarring of the airways (32.5%), asthma (25%), and pulmonary fibrosis, where scar tissue replaces healthy lung tissue (7.5%). Researchers noted that the pattern of lung damage resembled what’s seen in people exposed to chemical weapons like sulfur mustard.
Who Faces the Highest Risk
People with pre-existing respiratory conditions like asthma or COPD are at significantly greater risk of severe reactions. Their airways are already compromised, and the inflammatory response triggered by tear gas can push them into a breathing crisis more quickly than it would someone with healthy lungs. The same applies to people with cardiovascular conditions, since the stress response from pain and oxygen deprivation puts extra strain on the heart.
Children, older adults, and pregnant people are also considered higher-risk groups, though researchers have acknowledged that the evidence base for these populations is thin. Children breathe faster and inhale more gas relative to their body size. Older adults are more likely to have underlying heart or lung conditions that complicate exposure. The long-term effects on pregnant people and newborns remain largely unstudied, which itself is a concern given how frequently tear gas is deployed in populated areas.
CS Gas vs. CN Gas
An older tear gas compound called CN (chloroacetophenone) is more toxic than CS gas across nearly every measure. CN causes more severe skin reactions, including blistering and tissue swelling, and has a lower threshold for causing irritation. CS largely replaced CN in military and law enforcement use because it was considered less dangerous, but “less dangerous” is relative. CS can still cause all of the severe outcomes described above, particularly in enclosed environments. A third agent, OC (derived from pepper extract), is the least toxic of the three by irritation threshold but still carries respiratory risks at high concentrations.