Hydrogen Sulfide (H₂S)

A major hazard to first responders

• Sewers or marsh areas (anaerobic decomposition)
• May be suicide technique using H₂S
• Combination toilet cleanser and pesticide
• Rapidly absorbed after inhalation
• Respiratory paralysis and death in less than six minutes
• Local respiratory irritant and skin frostbite

Properties of H₂S

• Colourless, flammable, extremely hazardous gas
• Rotten egg smell
• Similar to cyanide, and is x5 more toxic than carbon monoxide
• Heavier than air
• Classically collects in basements, manholes, sewer lines, manure pits

H2S Exposure Features

Low	0 - 10 ppm	Irritation of eyes, nose & throat
Mod	10 - 50 ppm	Headache Dizziness Nausea & vomiting Coughing Breathing difficulties
High	50 - 200 ppm	Severe resp. tract irritation Acute conjunctivitis Shock & convulsions Coma Death in severe cases

Clinical

Low concentrations

• Eye irritation, sore throat, cough, nausea, SOB

Moderate

• Fatigue, vomiting, incoordination, headaches

High concentrations

• Seizures, amnesia, confusion, coma, death
• Chemical pneumonitis

Management

• Strict PPE for first responders
• Respiratory equipment
• Move victim to fresh air
• BVM if apnoeic
• High flow oxygen
• Amyl nitrate (inhalation)
• Sodium nitrite
• Bronchodilators
• Hyperbaric therapy