Health, Safety & Environment: surface
production operations
Hassan Ahmed Elsaed AbdElBaqy
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 Introduction :
(Health, Safety, and Environment (HSE) in the petroleum industry, particularly in the context of hydrogen
sulfide (H2S), is a critical aspect of operations to ensure the well-being of workers, protect the environment,
and maintain the integrity of facilities. Hydrogen sulfide is a colorless, flammable, and toxic gas that is
commonly found in the petroleum and natural gas industry. It poses significant risks to human health and
safety, as well as the surrounding environment.
Define the hydrogen sulfide and its Properties:
Hydrogen sulfide (H2S):
Hydrogen sulfide (H2S) is a chemical compound consisting of two
hydrogen atoms bonded to one sulfur atom. It is a colorless,
flammable, and highly toxic gas with a characteristic foul odor
reminiscent of rotten eggs. The smell is detectable even at low
concentrations, making it useful as a warning sign of its presence
Places of hydrogen sulfide formation:
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Naturally: In volcanic gases, hot springs, wetlands, and anoxic (oxygen-depleted) environments such as
deep ocean sediments and manure pits.
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Human activities: In the production of oil and natural gas, wastewater treatment, and the leather and
rayon industries.
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Properties of Hydrogen sulfide (H2S)
Physical Properties:
Chemical Properties:
Color: Colorless (makes it difficult to detect
Toxicity: Highly toxic, even in small amounts
visually).
(inhibits cellular respiration).
Odor: Rotten eggs, even in low concentrations.
Flammability: Highly flammable, can form
Oxidization: Can be oxidized to sulfur dioxide
(SO₂) and sulfuric acid (H₂SO₄) in the presence of
oxygen
explosive mixtures with air.
State: Gas at Specific condition.
Corrosiveness: Can corrode metals and other
Density: Heavier than air (about 20 % )
materials.
Acidity: Weak acid in aqueous solution.
Solubility: Highly soluble in water, forming a
Combustion: Burns in oxygen to form sulfur
weak acid solution.
dioxide (SO₂) and water, with potential for sulfur
trioxide (SO₃) formation and subsequent sulfuric
acid (H₂SO₄) formation in excess oxygen.
Autoignition temperature: 500 degrees.
Reactivity: Can react with various metals and
chemicals, forming sulfides
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Describe the Physiological effects of H2S and illustrated with toxicity table.
Physiological effects of H2S
Immediate Effects of H2S:
Irritation of the respiratory system (coughing, sore throat, shortness of breath).
Eye and skin irritation (redness, itching, burning sensation).
Headache, dizziness, and nausea.
Confusion and disorientation.
Bronchial constriction.
Vasodilation and potential drop in blood pressure.
Loss of consciousness, convulsions, and coma (at high concentrations).
Chronic Effects of H2S (resulting from repeated or prolonged exposure):
Respiratory system damage (chronic bronchitis, asthma-like symptoms).
Neurological effects (memory loss, cognitive impairment, mood disorders).
Cardiovascular system effects (hypotension, increased risk of cardiovascular disease).
Lung damage (pulmonary edema, fibrosis).
Liver and kidney damage.
Long-term exposure can increase the risk of chronic illnesses, such as respiratory infections, neurological
disorders, and certain cancers.
Factors influencing effects:
Concentration and duration of exposure: Higher concentrations and longer durations lead to more
severe effects.
Route of exposure: Inhalation most common, skin and ingestion less frequent but impactful.
Individual factors: Age, health conditions, and acclimatization play a role.
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Toxicity table of H2S
Concentration
0.01 - 1.5 ppm
2-5 ppm
20 ppm
50-100 ppm
100-150 ppm
200-300 ppm
500-700 ppm
700-1000 ppm
1000-2000 ppm
Effect with exposure time
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Odor threshold (when rotten egg smell is first becomes noticeable).
Odor becomes more offensive at 3-5 ppm.
Prolonged exposure may cause nausea, tearing of the eyes, headaches.
Airway problems (bronchial constriction) in some asthma patients.
TWA – time weighted average. The average exposure based on an eight hour
exposure period.
Possible fatigue, loss of appetite, headache, irritability, poor memory,
dizziness.
Above 30 ppm, odor is described as sweet or sickeningly sweet.
Slight conjunctivitis ("gas eye") and respiratory tract irritation after 1 hour.
May cause digestive upset and loss of appetite.
Coughing, eye irritation, loss of smell (olfactory fatigue) after 2-15 minutes.
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 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.
Death within minutes.
Nearly instant death.
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 Reference:
Hydrogen Sulfide - Hazards | Occupational Safety and Health Administration (osha.gov)
Hydrogen sulfide (nist.gov)
Hydrogen Sulfide (H2S): Preparation, Properties, Applications (scienceinfo.com)
Hydrogen Sulfide(H2S) Properties (25 Facts You Should Know) - (lambdageeks.com)
Production and physiological effects of hydrogen sulfide - PubMed (nih.gov)
Hydrogen Sulfide in Renal Physiology and Disease - PMC (nih.gov)
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