Kenneth D

January 20, 2026

14 min

Tear Gas: The Century-Old Chemical That Never Left the Battlefield

Picture this: a chemical weapon so potent it's banned in warfare under the 1993 Chemical Weapons Convention gets deployed nightly on American streets. We're talking about tear gas—the stuff that makes your eyes feel like they're melting and your lungs like they're collapsing. Police call it a "riot control agent." Scientists call it what it is: a chemical irritant designed to cause maximum misery without immediate death.

‍The Burning Question Nobody's Asking

Here's what'll surprise you: we know shockingly little about what this stuff does long-term. Most research comes from the 1960s and 70s, tested on healthy young men. What happens to kids? Pregnant women? People with asthma? Your guess is as good as the scientists'.

This isn't some relic from history books. Tear gas deployment has exploded in recent years, with Portland becoming America's most tear-gassed city in 2020. We're conducting a massive public health experiment, and nobody's tracking the results.

From Trenches to Streets: Chemistry's Dark Evolution

World War I: When Chemists Became Warlords

Tear gas didn't start as crowd control. It began as warfare.

August 1914 marked the first deployment when France fired grenades filled with ethyl bromoacetate at German positions. The amounts were so small the Germans didn't even notice. But the genie was out of the bottle.

Germany fired back in January 1915 with 18,000 shells of xylyl bromide tear gas at Russian troops during the Battle of Bolimov. The chemical froze in the brutal winter cold and failed spectacularly. Scientists went back to their labs with a singular goal: create something deadlier.

Enter Fritz Haber, the German chemist who'd win a Nobel Prize for synthesizing ammonia while simultaneously developing chemical weapons. On April 22, 1915, Germany released 188 tons of chlorine gas at Ypres, Belgium, causing 6,000-7,000 casualties in the first large-scale chemical attack.

The progression was relentless. Chlorine gave way to phosgene (six times deadlier), then mustard gas. By war's end, chemical weapons had caused 1.3 million casualties and 90,000-100,000 deaths. Most injuries came from phosgene, but tear gases remained the most commonly used chemical weapon throughout the conflict.

The Modern Arsenal: CS, CN, and Pepper Spray

Today's tear gas isn't your great-grandfather's version. The chemistry evolved, but the goal stayed the same: incapacitation through pain.

CS gas (2-chlorobenzalmalononitrile) emerged as the star player. Two American chemists, Ben Corson and Roger Stoughton, first synthesized it at Middlebury College in 1928—hence the name CS. But it sat in obscurity for decades until British scientists at Porton Down developed it as a riot control agent in the 1950s.

Why CS? It was more potent than its predecessor, CN (chloroacetophenone), but supposedly less toxic. The U.S. Army adopted it in 1959. Today, it's the most widely used tear gas globally.

CN gas dominated before CS took over. It's the main ingredient in the original Mace formulation. It hits the eyes hardest but it's nastier than CS—more toxic, more likely to cause serious side effects.

Pepper spray (OC, or oleoresin capsicum) took a different chemical route. It's an oily extract from hot peppers, concentrated to contain massive amounts of capsaicin. But we're not talking about hot sauce. OC sprays clock in at over 2,000,000 on the Scoville scale. Sriracha measures 1,000-2,500 for comparison.

The Body's Response: Chemistry Meets Pain

How Tear Gas Actually Works

Despite the name, tear gas is a misnomer on two counts. First, it's not a gas—it's a solid powder dispersed as an aerosol. Second, tears are just one symptom among many.

The real action happens at pain receptors called TRPA1 and TRPV1. These are the same receptors that detect wasabi, mustard oil, and chili peppers. CS, CN, and CR gases activate TRPA1 receptors. Pepper spray activates TRPV1. Both pathways lead to the same miserable destination: your nervous system floods with pain signals.

Dr. Sven-Eric Jordt, who's studied tear gas for over a decade, prefers calling it "pain gas" because that's what it really is. The chemicals don't paralyze like nerve agents. They trigger maximum suffering to force people to flee.

When CS contacts moisture—in your eyes, airways, or on your skin—it causes an instant burning sensation. Your eyes slam shut involuntarily. Tears stream. Your nose produces copious mucus. You cough profusely. Your chest tightens. Breathing becomes difficult.

Research published by the National Academy of Sciences shows that 4 mg/m³ will disperse most rioters within one minute. At 10 mg/m³, even trained soldiers can't tolerate exposure.

Immediate Effects: The First 30 Minutes

The onset is brutal and immediate. Most symptoms peak within seconds after exposure.

Eyes: Burning pain, excessive tearing, redness, swelling. At high concentrations or close-range impacts, corneal abrasions or even blindness can occur.
Respiratory system: Coughing, choking, chest tightness, difficulty breathing. For people with asthma or chronic obstructive pulmonary disease, this can trigger severe bronchospasm requiring hospitalization.
Skin: Stinging, itching, redness. Higher concentrations cause chemical burns and blistering.
Gastrointestinal: Nausea, vomiting, abdominal pain.

Most people recover within 15-30 minutes once removed from exposure. Or so the official line goes. That timeframe comes from controlled studies on healthy volunteers—not real-world mass exposures.

Long-Term Effects: The Research Gap

Here's where things get murky and concerning.

A 2014 Turkish study examined 93 men who'd been repeatedly exposed to tear gas during protests. Compared to non-exposed controls, they showed 2-2.5 times higher rates of chronic cough, chest tightness, and shortness of breath, plus significantly reduced lung function. The researchers concluded tear gas-exposed subjects faced long-term respiratory health consequences.

A 2023 Chilean study analyzed respiratory emergency visits during the 2019 social uprising when police deployed massive amounts of tear gas. Vulnerable populations—infants under 1 year and adults over 65 who weren't even protesting—showed dramatic increases in respiratory emergencies during tear gas exposure periods.

A University of Minnesota Medical School systematic review found that most tear gas research dates from the 1960s-70s and hasn't been updated despite evolving formulations and deployment methods. The researchers noted severe gaps: studies excluded women, children, elderly, and people with pre-existing conditions—exactly the populations most at risk.

Recent findings include disturbing additions:

Menstrual disruptions: In a Portland study, 54.5% of women exposed to tear gas during 2020 protests reported menstrual cycle changes
Mental health impacts: Anxiety, depression, and PTSD symptoms in repeatedly exposed individuals
Lingering respiratory symptoms: Cough and breathing difficulties persisting for months after exposure

Three Perspectives on Tear Gas Use

Mainstream Medical Consensus: Necessary Evil with Serious Concerns

The medical establishment walks a tightrope. They acknowledge tear gas as a "less lethal" alternative to bullets while expressing serious reservations.

The CDC and National Institutes of Health classify tear gas as a "riot control agent" rather than a weapon of mass destruction. Their position: when used appropriately in open spaces against healthy adults, tear gas causes temporary discomfort without lasting harm.

Major medical institutions emphasize caveats: vulnerable populations face disproportionate risk—people with asthma, chronic lung disease, cardiovascular conditions, pregnant women, children, and the elderly.

The American Journal of Public Health published research showing that current exposure guidelines are based on lethal dose studies in animals, scaled to humans using imprecise formulas. The EPA identifies no safe exposure level where effects could be considered mild.

The mainstream medical view essentially says: tear gas is preferable to bullets, but we're using it far more broadly than the science supports.

Alternative/Integrative Medicine Perspective: Undisclosed Toxic Load

Integrative health practitioners raise concerns that conventional medicine overlooks: cumulative toxic burden and systemic inflammation.

Practitioners at functional medicine centers emphasize that tear gas exposure adds to existing body burdens from air pollution, food additives, plastics, and other environmental toxins. Tear gas formulations often include unlisted additives, solvents, and propellants.

From this perspective, the "temporary discomfort" narrative ignores several mechanisms:

Oxidative stress: Chemical irritants trigger free radical production
Inflammatory cascade: Systemic inflammation may persist after acute symptoms resolve
Endocrine disruption: Documented menstrual changes suggest hormonal effects beyond simple stress
Microbiome disruption: Respiratory tract chemicals may alter beneficial bacterial populations

The integrative medicine view: we're conducting an uncontrolled experiment on human health, measuring only obvious outcomes while missing systemic impacts that may take years to manifest.

Social Media and Activist Perspective: Chemical Warfare Against Citizens

On platforms like Twitter, Instagram, and Reddit, the narrative is unambiguous: tear gas is a weapon of oppression deployed against people exercising constitutional rights.

Activists share firsthand accounts that differ dramatically from official descriptions. Reddit's r/Portland exploded with posts during 2020 describing symptoms lasting days or weeks: persistent cough, difficulty breathing, skin burns, neurological effects.

The influencer narrative emphasizes points dismissed by official sources:

Indiscriminate deployment: Tear gas doesn't distinguish between violent rioters and peaceful protesters, bystanders, journalists, or medics
Escalation tool: Rather than de-escalating violence, tear gas often provokes panic
Lack of accountability: No tracking of who gets gassed, how often, with what chemicals

Popular YouTube channels connected dots between military use bans and domestic deployment. If it's illegal in warfare, why is it legal on city streets?

Synthesis: Bridging the Gap

Three perspectives, wildly different conclusions. Where's the truth?

Areas of agreement:

Tear gas causes intense, immediate suffering—that's its purpose
Current research has massive gaps, particularly for vulnerable populations
Deployment has increased dramatically without corresponding safety research

Key disagreements:

Mainstream medicine: Temporary effects, acceptable risk for crowd control
Integrative health: Unmeasured systemic impacts, cumulative toxic burden
Activists/public: Disproportionate use, chemical warfare against citizens

The scientific evidence actually supports concerns from all three camps. The Turkish respiratory study, Chilean infant emergency data, and Portland menstrual disruption findings directly contradict claims of purely temporary effects. These are peer-reviewed publications, not anecdotes.

The mechanism research on TRPA1 and TRPV1 receptors confirms that tear gas works by triggering pain pathways. There's no gentler interpretation.

The uncomfortable synthesis: We're using a century-old chemical weapon, banned in warfare, on domestic populations without adequate research on long-term health effects. The "it's safe" narrative rests on outdated studies of healthy young men in controlled conditions, not real-world mass deployments.

Medical authorities acknowledge serious risks to vulnerable groups but haven't defined protocols for avoiding those exposures. Integrative practitioners rightly point out unmeasured systemic effects. Activists accurately note the disconnect between warfare bans and street deployment.

None of this means tear gas is as deadly as sarin or mustard gas. But it does mean we're operating with far less knowledge than we pretend.

What This All Means

Tear gas sits in a strange regulatory limbo: banned in warfare as a chemical weapon, routine in domestic law enforcement. That contradiction reveals uncomfortable truths.

The science doesn't support the safety claims we've been told. We have century-old chemicals, decades-old research on limited populations, and modern deployment at scales never studied. Add documented long-term respiratory effects, menstrual disruptions, and infant respiratory emergencies, and you get a picture very different from "temporary discomfort."

Does this mean tear gas is as dangerous as nerve agents? No. But it's not as safe as officials claim either. The gaps in our knowledge are massive and concerning.

The path forward requires honest assessment, not reassuring narratives. We need actual research on actual impacts—long-term health studies, vulnerable population effects. Until then, every deployment is an experiment without controls or informed consent.

What is Tear Gas's LyfeiQ Score?

Credibility Rating: 3/10

Scientific Evidence for Safety in Humans: 2/10 (mostly 1960s-70s data on healthy young men; modern deployment patterns unstudied)
Long-Term Health Data Quality: 1/10 (extremely limited follow-up beyond acute exposure)
Vulnerable Population Protection: 1/10 (children, elderly, pregnant women inadequately studied)
Transparency of Formulations: 2/10 (undisclosed additives and solvents common)
Regulatory Oversight: 4/10 (banned in warfare but routine domestic use)
Alternative Options Available: 6/10 (other crowd control methods exist but aren't prioritized)

Medical Consensus: Acceptable for limited use in specific circumstances, serious concerns about widespread deployment and effects on vulnerable populations

LyfeiQ Score: 3/10

Tear gas represents a chemical we've used for a century without conducting the research to justify that use. The "less lethal" label doesn't mean "safe"—it means "probably won't kill you immediately if you're young and healthy."

The science we do have is concerning: long-term respiratory effects, infant emergency spikes, menstrual disruptions. What we don't know is even more concerning: cancer risk, reproductive effects, developmental impacts, chronic disease associations.

Until we have real data on real-world deployment effects, treat official safety reassurances skeptically. This is a chemical weapon deployed without the research to back up its routine use.