World Cup Ready: Managing Crowd Control Chemical Exposures

Photo of a soccer field with the words "World cup ready: Crowd control chemicals"

By Colleen Cowdery, MD

As Washington prepares to host upcoming World Cup matches in Seattle and Fan Zones across the state, we’re reviewing potential poisonings at mass gatherings and their clinical management. This information is intended for general education and public health awareness. Always contact us for specific patient care (1-800-222-1222).

Crowd control chemicals like tear gas and pepper spray may be used for large-scale crowd management or carried by individuals for personal defense. These local irritants target skin and mucous membranes in the eyes, nose, throat, and lungs. Effects begin within seconds, leading to their use by law enforcement and the military to quickly break up large crowds.

Chemicals
  • CN (chloroacetophenone) & CS (chlorobenzylidenemalononitrile): Powder formulations commonly known as “tear gas”
  • OC (oleoresin capsicum): Liquid formulation commonly known as “pepper spray”
  • Other compounds include PS (chloropicrin), CA (bromobenzylcyanide), and CR (dibenzoxazepine). These alternative agents are either not used or are very infrequently encountered within the United States.

When deployed, tear gases and pepper spray form dense clouds. Because the chemicals are heavier than ambient air, the clouds tend to travel close to the ground. As a result, they can settle in higher concentrations in low-lying areas, such as stairwells, basements, depressions in outdoor viewing areas, and stadium concourses.

Clinical features

Significant irritation to the skin and mucous membranes begins within seconds of exposure. Common effects include:

  • Excessive tearing of the eyes (lacrimation)
  • Runny nose
  • Drooling
  • Cough
  • Rash
  • Nausea and vomiting

Severe complications

  • At higher concentrations or in sensitive individuals (such as those with asthma, chronic lung disease, or a history of smoking), tear gas agents may cause wheezing, chest tightness, and difficulty breathing.
  • Prolonged exposure or high concentrations can lead to severe lung damage (i.e., chemical pneumonitis).
  • High concentrations can lead to chemical burns on skin, throat, or lungs.
Treatment
  • Management is supportive, focused on ending continued exposure and decontaminating. There are no antidotes.
  • Move to fresh air immediately. Evacuate enclosed buildings or crowded stadium zones, and direct outdoor patients to the highest ground possible to avoid low-lying chemical clouds.
  • Call 911/transport to hospital immediately if an exposed individual is unresponsive or experiencing severe respiratory distress.
  • Have patients with a history of asthma use their prescribed rescue inhaler immediately, but do not delay contacting emergency medical services/transportation to hospital if breathing difficulties persist.
  • Wear fresh gloves that have not been exposed to chemical-contaminated air prior to treating a patient’s face or eyes, to prevent secondary exposure. Always change gloves between patients to prevent secondary exposure. If you do not have gloves, wash your hands thoroughly with soap and water before and after treating a patient’s face or eyes to prevent secondary exposure to either them or you.
  • Remove contaminated clothing quickly by cutting or unbuttoning shirts. Do not pull clothing over the head, as this re-exposes the eyes, nose, and mouth to the chemicals. If you must pull a shirt over the head, the patient should tightly close their eyes/mouth and hold their breath if possible, and the shirt should be pulled forward so as not to make contact with the face while being removed.
  • Wash the body and skin with copious amounts of soap and water. Tilt the patient’s head far forward or backward when washing hair to prevent contaminated runoff from flowing directly into the eyes, nose, or mouth.
  • If the patient is wearing contact lenses, have them wash their hands thoroughly and remove their contact lenses. Discard the contact lenses, as they can absorb the chemicals and re-expose the eye.
  • Flush eyes with plain water for 10 to 15 minutes if the patient experiences pain or burning. Do not use milk, baby shampoo, or other substances to flush the eyes. Not all crowd control agents are oil-based, so plain water is safest.
  • Do not allow the patient to rub their eyes, as this can worsen symptoms and increase the risk of eye injury.

For real-time expert guidance or to determine if a patient requires additional care, contact Washington Poison Center:

  • Emergency Help Line: 1-800-222-1222
  • Text Line: 206-526-2121
  • Live Chat: wapc.org

View our one pager for community members on crowd control agents. 

screen shot of "crowd control chemicals" fact sheet

Non-chemical injuries

Remain aware that patients from a mass gathering with chemical agent release are at elevated risk for non-chemical injuries as well, including trauma related to falls, stampedes/crushes, direct intentional trauma from hands/feet/batons, and other sources.

Kinetic impact projectiles such as beanbags, rubber bullets, or thrown/shot chemical agent canisters can cause significant damage, particularly in cases of facial and ocular trauma.

Non-chemical injuries should be triaged and treated as is typical for trauma. Stabilization of traumatic threats to life and limb take priority over crowd-control agent decontamination.

References

CDC Chemical Fact Sheets: Riot Control Agents (https://www.cdc.gov/chemical-emergencies/chemical-fact-sheets/riot-control-agents.html)

Goldfrank’s Toxicologic Emergencies, chapter 126 (Chemical Weapons)

Horowitz, B. Zane. “Tear gas in America: Cry the beloved country.” Toxicology Communications 4.1 (2020): 59-61.