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

L o w	0 - 10 ppm	Irritation of eyes, nose & throat
M o d	10 - 50 ppm	Headache Dizziness Nausea & vomiting Coughing Breathing difficulties
H i g h	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.