Tear Gas and Pepper Spray

Background

Chemical irritant
Either powder or 1% - 5% aerosol spray
Commonest used are
- chlorobenzylidene-malononitrile
- (CS after chemists Corson and Stoughton)
- chloroacetophenone (CN or "Mace")
- dibenzoxazepine (CR)
- oleoresin capsicum (OC)
- pelargonic acid vanillylamide (PAVA)
Pepper strength is measured in Scoville heat units
- Green pepper = 0, pure capsaicin = 15 million units
Irritant effect from action of chlorine or cyanide groups
Immediate release of inflammatory P substance
Effects enhanced by heat and by high humidity
Rapid onset time & short duration of effects
Wide margin of safety between the incapacitating dose (ICt 50, the concentration (C) that causes incapacitation (I) in 50% of individuals after one minute (t=time)) and the lethal dose (LCt 50, the concentration that causes death (L) in 50% of individuals after one minute)

Clinical manifestations and potential complications
Area	Clinical	Complications	Potential sequelae
Eyes	Tearing, burning sensation, blepharospasm, photophobia, corneal oedema	Keratitis, corneal erosion, intraocular haemorrhage	Cataract, glaucoma
Area	Severe rhinorrhoea, sneeze, cough, dyspnoea, pharyngitis, bronchitis	Bronchospasm, hypoxia, delayed pulmonary oedema	Asthma
CVS	Hypertension	Heart failure, cerebral haemorrhage
Skin	Rash, oedema, erythema, blistering	Irritant dermatitis, facial oedema	Allergic dermatitis
GIT	Buccal irritation, salivation, abdo. pain, D&V	Liver toxicity
Neuro	Trembling, agitation, anxiety

Medical teams should wear protection for their own safety and to prevent secondary contamination
Contaminated clothes removed; eyes and affected skin surfaces should be cleaned with water
For pulmonary symptoms, oxygen therapy, β2-mimetics and ipratropium aerosols may be required
For pulmonary symptoms, a 24-48 hour stay in CDU may be required
Remove contact lenses
Irrigate eyes with saline or Diphoterine (in storage cupboard, decontamination room CUH)
Wash skin with soap and water or Diphoterine (in storage cupboard, decontamination room CUH)
Severe skin lesions - wash then topical steroids