Hydrogen Sulfide (H2S)



HS gas smells like rotten eggs

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.


Content by Dr. √ćomhar O' Sullivan 27/04/2011. Last review Dr IOS 12/05/13.