II. Definitions
- Riot Control Agent (e.g. Tear Gas)
- Aerosolized powders used by police and military to suppress crowds by causing eye, skin and nose irritation
- Dispersed via handheld atomizer or paintballs
III. Causes: Common Riot Control Agents
- Commonly used Riot Control Agents
- Oleoresin of Capsicum (OC, Pepper Spray)
- Oily concentrated Capsaicin extract from chili peppers (e.g. jalapenos)
- Scoville units may approach 2,00,000 (contrast with jalapenos, Scoville 2000)
- Chlorobenzylidenemalononitrile (CS) Powder
- Most common agent used in U.S. by police and border control agents (developed 1928)
- Has replaced CN, due to less toxicity and less severe systemic toxicity
- Half life for CS and metabolites: 5 to 660 seconds (11 minutes)
- Chloroacetophenone (CN, Tear Gas, mace)
- More skin irritation than with CS
- Oleoresin of Capsicum (OC, Pepper Spray)
- Older agents with greater toxicity and potency
- Chlorodihydrophenarsazine (DM)
- Dibenzoxazepine (CR) Gas
IV. Mechanism
- All agents activate the TRPA1 pain receptors, causing irritation and inflammation at skin, eye, nose
- Substance P and CGRP are also released
- Riot Control Agent exposure to CN or CS is rarely lethal unless in enclosed spaces
- Mucosal Irritants are dissolved in solvents, allowing for aerosolization
- Solvents may also be associated with specific toxicity
V. Findings: Signs and Symptoms
- Eye
- Eye tearing (Lacrimation)
- Conjunctivitis
- Chemosis
- Blepharospasm
- Eyelid Edema
- Nose
- Nasal congestion
- Rhinorrhea
-
Lung
- Cough
- Bronchospasm
- Hemoptysis
- Copious airway secretions
- Exacerbation of Asthma, COPD or other chronic lung disease
- Gastrointestinal
- Skin
- Skin burning Sensation
- Contact Dermatitis (uncommon)
- Skin bullae (prolonged exposure)
VI. Pharmacokinetics
- Onset of ocular and respiratory symptoms: 20 to 60 seconds after exposure
- Ocular irritation duration: 10-30 minutes (photophobia may persist)
- Contact Dermatitis or skin bullae duration: 4 days
VII. Management
- Preparation
- All rescuers should wear Personal Protective Equipment (PPE, Eye Protection, masks, gowns)
-
Decontamination
- Evacuate patient to open, fresh air
- Remove all contaminated clothing
- Wash all skin with soap and water (remove all traces of chemical)
- Eye Irrigation for 15 minutes
- Consider Diphoterine Wash (Decontamination and chelating solution)
-
ABC Management
- Airway Management
- Supplemental Oxygen as needed
- Oral secretion and nasal secretion suctioning
- Acute bronchospasm management (e.g. AlbuterolInhaler or Nebulized Albuterol)
-
Contact Dermatitis Management
- Wash intact exposed skin with soap and water
- Irrigate broken skin with saline
- Burn Management as needed
- Eye exposure
- Irrigation with water of saline for 10-15 minutes if symptoms present
- Complete Eye Injury exam (Slit Lamp, Fluorescein stain)
VIII. Complications: Rare but Serious (depending on agent used)
- Respiratory complications (rare)
- Ocular complications
- Hyphema
- Uveitis
- Necrotizing Keratitis
- Traumatic optic Neuropathy
- Blunt Trauma and Thermal Burns from delivery device impacts
- Significant burn injuries
- Limb Amputations or functional loss
- Permanent Vision Loss
IX. Prevention
- Limit exposure to mucosal agents (immediately leave areas where irritants are dispersed)
X. Resources
- CDC Riot Control Agents
XI. References
- Tomaszeski (2020) Crit Dec Emerg Med 34(6): 32
- Vedula and Jasani (2025) Crit Dec Emerg Med 39(5): 4-14
- Olajos (2001) J Appl Toxicol 21(5):355-91 +pmid:11746179 [PubMed]
- Schep (2015) J R Army Med Corps 161(2):94-9 [PubMed]