Hydrogen Sulfide Health Effects

Hydrogen sulfide is a colorless, flammable, extremely hazardous gas with a “rotten egg” smell and it is produced by the break down of animal wastes or manure. It is heavier than air and can collect in low-lying and enclosed poorly ventilated areas such as reception pits, ditches, or manholes.  In manure processing buildings it may collect in areas with low air movement, dry motor pits or walled off areas.


 Concentration (ppm)

 Short Term Symptoms/Effects

 0.00011-0.00033  Typical background concentrations

 Odor threshold (when rotten egg smell is first noticeable to some.)

Odor becomes more offensive at 3-5 ppm. Above 30 ppm, odor described as sweet or sickeningly sweet.


 Prolonged exposure may cause nausea, tearing of eyes, headaches or loss of sleep.

Airway problems (bronchial constriction) in some asthma patients.

 20  Possible fatigue, loss of appetite, headache, irritability, poor memory, dizziness.

 Slight conjunctivitis (eye irritation and redness).

Respiratory tract irritation after 1 hour.

May cause digestive upset or loss of appetite.


 IDLH- Immediately Dangerous to Life and Health

Leave area and get to your safety zone

Coughing, eye irritation, loss of sense of smell

Altered breathing, drowsiness after 15-30 minutes

Throat irritation after 1 hour

Gradual increase in severity of symptoms over several hours

Death may occur after 48 hours.


 Marked conjunctivitis and respiratory tract irritation after 1 hour

Pulmonary edema (fluid in lungs) may occur from prolonged exposure


 Staggering, collapse in 5 minutes. Serious damage to the eyes in 30 minutes

Death after 30-60 minutes.


 Rapid unconsciousness, “knockdown” or immediate collapse within 1 to 2 breaths

Breathing stops.

Death within minutes.

1000-2000  Nearly instant death



What about long term health effects?

Some people who breathed in levels of hydrogen sulfide high enough to become unconscious continue to have headaches and poor attention span, memory, and motor function after waking up. Problems with the cardiovascular system have also been reported at exposures above permissible limits. People who have asthma may be more sensitive to hydrogen sulfide exposure. That is, they may have difficulty breathing at levels lower than people without asthma.


Source: https://www.osha.gov/SLTC/hydrogensulfide/hazards.html. Accessed November 2, 2016.

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