Tear gas, pepper spray, and crowd-control agent decontamination and first aid¶

Chemical crowd-control agents (commonly referred to as riot control agents or lachrymators) include CS gas (2-chlorobenzalmalononitrile), OC pepper spray (oleoresin capsicum), PAVA (pelargonic acid vanillylamide, a synthetic capsaicinoid), and CN gas (chloroacetophenone / Mace). Whether you are an uninvolved commuter caught near a demonstration, a neighborhood resident whose open apartment window drew in drifting street smoke, a journalist, or a pedestrian accidentally exposed to personal defense spray, acute exposure causes immediate, intense pain. Within two seconds of contact with the moist mucous membranes of the eyes, nose, throat, and damp skin, these chemical compounds activate pain receptors (specifically TRPA1 and TRPV1 ion channels), triggering involuntary eyelid spasms (blepharospasm), temporary functional blindness, choking, chest tightness, and intense burning across the skin.

For healthy adults in open air, the acute effects of tear gas and pepper spray are usually temporary and begin subsiding within 15 to 45 minutes after moving to fresh air and flushing properly. However, in enclosed spaces, high concentrations, or in people with asthma, chronic obstructive pulmonary disease (COPD), cardiovascular disease, or contact lenses, chemical crowd-control agents can trigger life-threatening bronchospasm (severe asthma attacks), laryngospasm, corneal abrasions, and second-degree chemical skin burns. Knowing how to escape the aerosol plume upwind and uphill, flush eyes properly with clean water or sterile saline without rubbing, avoid dangerous street myths like pouring milk or antacids into the eyes, and decontaminate clothing safely at home prevents permanent eye and lung injury.

Do this now¶

1. Move immediately to fresh air by walking UPWIND and UPHILL (higher elevation). Tear gas aerosols and vaporized particles are significantly heavier than air and sink into low-lying streets, subways, basements, and ground floors. Walk calmly (do not run, as running makes you breathe deeper and faster) perpendicular to or into the wind, and climb to higher ground or an upper-floor balcony away from the white smoke cloud.
2. Never rub your eyes, face, or skin with your hands. CS gas is not actually a gas at room temperature; it is a cloud of microscopic, sharp crystalline solid powder particles. Rubbing your eyelids grinds these microscopic crystals directly across your cornea like sandpaper, causing painful corneal abrasions, and spreads oily OC pepper spray deeper into your skin pores.
3. Remove contact lenses immediately with clean fingers and throw soft lenses away. Contact lenses trap concentrated chemical crystals and capsaicin oils directly against your eyeball underneath the lens, preventing water from washing the chemical out and melting or permanently contaminating soft hydrogel lenses. Wash or wipe your fingers first, pinch the lenses out immediately, and discard soft lenses permanently.
4. Blink rapidly and flush your eyes from the inner corner (near the nose) outward using clean cool water or sterile saline. Tilt your head sideways over a sink or ground area so the worse eye is facing downward (so contaminated runoff water does not wash across the bridge of your nose into your other eye or down into your mouth). Pour a steady, gentle stream of clean drinking water or sterile 0.9% normal saline from the inner corner of the eye near the nose outward toward the ear for 10 to 15 continuous minutes.
5. NEVER pour milk, liquid antacids (Maalox), vinegar, baking soda paste, or cooking oil into your eyes. Despite widespread internet rumors, pouring unsterile dairy milk, flavoured liquid antacids, or vinegar into eyes that have microscopic chemical scratches introduces bacteria (Pseudomonas and Staphylococcus), fungi, and particulate grit that can cause sight-threatening bacterial keratitis (corneal ulcers). Use only sterile saline or clean potable water inside the eyes.
6. Strip off contaminated outer clothing without pulling shirts over your head, and take a COLD shower. Once you reach a safe bathroom, cut off contaminated pull-over t-shirts with scissors (or unbutton shirts) so you do not drag powder-coated fabric back across your face and eyes. Step into a cold water shower for the first 5 minutes before applying mild dish soap: hot or warm water opens skin pores and reactivates intense burning from crystalline CS powder and capsaicin oil.

Emergency field triage and decontamination flowchart¶

Follow this clinical sequence from the moment of exposure through home clothing decontamination.

flowchart TD
    A["Exposed to Tear Gas (CS/CN) or Pepper Spray (OC/PAVA)"] --> B["Stay Calm: Breathe Slowly Through Nose/Cloth & Move Upwind and Uphill"]
    B --> C{"Any severe wheezing, inability to speak full sentences, or chest pain?"}
    C -->|"Yes: Respiratory Emergency"| D["Call 911 / 112 / 999 Immediately, Sit Upright, Use Rescue Inhaler (Albuterol)"]
    C -->|"No: Eye and Skin Burning Only"| E["DO NOT RUB EYES: Remove and Discard Contact Lenses Immediately"]
    E --> F["Tilt Head Sideways (Affected Eye Down) & Flush Inner-to-Outer Corner"]
    F --> G["Irrigate Continuously for 10 to 15 Minutes with Sterile Saline or Clean Water Only"]
    G --> H["At Home: Seal Outer Clothes in Plastic Bag (Do Not Pull Shirt Over Face)"]
    H --> I["Rinse Hair and Skin with COLD Water for 5 Minutes First, Then Wash with Mild Dish Soap"]
    I --> J{"Does severe eye pain, vision blur, or blistering persist past 60 minutes?"}
    J -->|"Yes"| K["Seek Urgent Ophthalmological or Emergency Room Exam for Corneal Abrasion"]
    J -->|"No"| L["Rest in Ventilated Room & Launder Clothes Separately in Cold Water Twice"]

Identifying the chemical agent: CS Tear Gas vs. OC Pepper Spray vs. CN Mace¶

Understanding which chemical agent you were exposed to explains how it behaves on your body and on household surfaces. While all riot control agents cause immediate tearing and burning, their physical chemistry differs fundamentally.

Why CS "Gas" is actually a microscopic solid powder¶

The most important fact to understand about CS tear gas is that it is not a true gas. At normal outdoor temperatures, CS is a white solid crystal similar to talcum powder or finely ground glass. When a tear-gas canister is fired, an internal pyrotechnic charge heats the solid CS until it vaporizes into the air; as soon as that hot vapor hits the cool outdoor air, it condenses back into a dense cloud of microscopic solid particles measuring 1 to 10 micrometers across.

Because CS is a solid powder that reacts chemically with moisture:

• Sweat and humidity activate the burn: CS crystals stick to sweaty foreheads, necks, waistbands, and wet shirts. As the crystal slowly reacts with skin moisture (hydrolysis), it releases microscopic amounts of hydrochloric acid and irritant breakdown products directly onto your nerve endings.
• Blowing dry air helps before washing: Once you walk out of a CS cloud into fresh wind, standing in a strong breeze with your arms outstretched for 3 to 5 minutes allows the wind to blow loose dry CS powder off your hair and clothes before water ever touches it.

Step-by-step eye irrigation protocol (and why street remedies cause blindness)¶

Your eyes are the most sensitive target of chemical crowd-control agents. When CS crystals or OC pepper spray droplets land on the tear film of the cornea, the trigeminal nerve triggers an immediate protective reflex called blepharospasm, your eyelids slam shut so tightly that you cannot open them by willpower alone.

How to flush your own or another person's eyes safely¶

1. Position the head tilted sideways with the affected eye LOW: Have the person lean forward or tilt their head sideways at a 45-to-90-degree angle so the eye being flushed is on the bottom. Never tilt the head straight back while pouring water over the forehead: tilting the head back washes the chemical powder off the forehead and eyebrows straight into the eyes and down into the mouth.
2. Hold the eyelids open gently with two clean fingers: Because involuntary blepharospasm clamps the eyelids shut, water poured over closed eyelids does nothing to clean the eyeball. Place your clean thumb on the upper eyebrow bone and your index finger on the lower cheekbone (never pressing directly on the eyeball itself) and gently pull the eyelids apart so the liquid stream hits the surface of the eye.
3. Pour from the INNER corner (by the bridge of the nose) to the OUTER corner: Hold a squirt bottle of sterile 0.9% normal saline eye wash or a clean bottle of drinking water 2.5 to 5 centimeters (1 to 2 inches) above the inner corner of the eye (next to the bridge of the nose). Let a steady, low-pressure stream flow across the eye and run off the outer corner by the temple onto the ground. Have the person roll their eyeball up, down, left, and right while flushing so particles trapped under the upper and lower eyelids are washed out.
4. Flush for a full 10 to 15 minutes: Do not stop after a two-second splash. Brief splashes of water on CS crystals briefly wet the powder and can make it sting more for 10 seconds before the volume of water carries the crystals away. Continuous irrigation for 10 to 15 minutes is what mechanically washes every crystal and oil droplet off the cornea.

Why you must NEVER put milk, Maalox (antacids), vinegar, or baby shampoo inside your eyes¶

During demonstrations and civil unrest, well-meaning bystanders frequently walk around carrying jugs of dairy milk, 50/50 mixtures of liquid antacid (LAW: Liquid Antacid and Water, such as Maalox or Mylanta), baking soda water, or baby shampoo to squirt into people's eyes. Ophthalmologists, poison control centers, and the American Academy of Ophthalmology warn strictly against putting any substance other than sterile saline or clean potable water into the human eye:

Skin and hair decontamination: the cold-water and dish-soap protocol¶

Once your eyes can open and your breathing is steady, you must remove the chemical residue clinging to your hair, face, neck, and clothing before you touch furniture, car seats, or family members at home.

Step 1: Undressing outside or inside a tiled bathroom¶

• Do not walk through your carpeted living room or sit on your fabric sofa wearing clothes exposed to tear gas or pepper spray. CS crystals and OC oils transfer instantly to upholstery and will off-gas and burn anyone who sits on that couch for weeks.
• Step into a tiled entryway, garage, or bathroom. Put on disposable nitrile or latex gloves if you have them.
• Never pull a contaminated t-shirt, sweatshirt, or sweater up over your head. Pulling a tight collar over your face scrapes all the CS powder and pepper spray that settled on your shoulders and chest straight into your eyes, nose, and mouth. Either unbutton the garment, pull your arms inside the sleeves first to lift it away from your face, or use heavy scissors to cut the shirt straight up the front seam and peel it off backward.
• Drop all contaminated clothes, shoes, and backpacks directly into a heavy-duty plastic trash bag and tie it shut until you are ready to wash them separately.

Step 2: The 5-minute COLD water shower rule¶

When you step into the shower to wash tear gas or pepper spray off your hair and body, turn the temperature knob all the way to COLD (or cool tepid water) for the first 5 minutes:

1. Why hot showers are agony: Hot or warm water causes immediate cutaneous vasodilation (rushing blood to the skin), opens sweat glands and pores wide, and melts oily OC resin and CS crystals so they penetrate deeper into the skin, reactivating a violent wave of burning across your entire body.
2. Stand upright and lean your head backward (or forward over the tub) when rinsing hair: Your hair acts like a giant air filter that catches huge amounts of airborne tear-gas dust. When you first rinse your hair with cold water, do not let the water from your scalp run down over your forehead into your eyes and down your chest into your groin (the groin and genitals have ultra-sensitive mucous membranes that will burn intensely if contaminated shower runoff washes down your torso). Bend forward at the waist so hair water drains straight onto the shower floor.
3. Wash skin exposed to OC pepper spray with mild degreasing liquid dish soap: Because OC pepper spray is a chili oil resin (capsaicin), plain water alone rolls right off the oil on your skin. After rinsing loose powder off with cold water for 5 minutes, lather your face (keeping eyelids gently closed), neck, arms, and hands with mild liquid dishwashing detergent (such as Dawn or Fairy liquid) or a gentle oil-free facial cleanser to emulsify and lift the capsaicin oil off your skin, then rinse thoroughly with cool water.
4. Pat dry with disposable paper towels rather than rubbing vigorously with a cloth bath towel.

How to protect your apartment or house if tear gas is deployed on your street¶

When crowd-control agents are deployed on urban streets outside residential apartment buildings, ground-floor and second-floor units frequently fill with drifting CS aerosol through window cracks, air conditioners, and bathroom vents.

How to safely launder tear-gas or pepper-spray clothing¶

Never toss a tear-gas-soaked jacket into the washing machine along with your child's clothes or your bedsheets; the chemical will transfer onto every item in the drum.

1. Wear disposable nitrile gloves when transferring clothes from the plastic bag into the washing machine.
2. Set the washing machine to COLD water only, highest water level, and an extra rinse cycle.
3. Add standard liquid laundry detergent plus 120 milliliters (one-half cup) of baking soda (sodium bicarbonate), which helps alkaline-hydrolyze and neutralize CS residue during the wash.
4. Run the cold wash cycle twice before touching the clothes.
5. Hang the clothes to air-dry outdoors or on a rack rather than putting them into a hot clothes dryer after the first wash (high dryer heat can bake any remaining trace of CS or OC into synthetic fibers and vent irritating fumes into your laundry room).
6. For leather boots, nylon backpacks, eyeglasses, and smartphones that cannot go in the washing machine, wipe them down three times outdoors using disposable paper towels soaked in cool water and mild dish soap, discarding each paper towel after a single swipe.

Frequently asked questions¶

Sources checked¶

• Centers for Disease Control and Prevention (CDC), Emergency Preparedness and Response: Facts About Riot Control Agents (CS, CN, and OC) and Medical Management Guidelines (United States)
• National Institutes of Health (NIH) and National Library of Medicine, Wireless Information System for Emergency Responders (WISER): Tear Gas and Oleoresin Capsicum Decontamination Protocols (United States)
• United Kingdom Health Security Agency (UKHSA), CS Spray and Riot Control Agents: Toxicological Overview, Incident Management, and Decontamination Guidance (United Kingdom)
• American Academy of Ophthalmology (AAO), Eye Safety and First Aid Guidelines for Chemical Exposure, Tear Gas, and Pepper Spray (United States)
• Organisation for the Prohibition of Chemical Weapons (OPCW) and World Health Organization (WHO), Health Aspects of Chemical and Biological Weapons: Riot Control Agents (International)

Related guides¶

• Civil unrest
• Eye injuries
• Asthma attack
• Severe burns and chemical flushing