Hydrogen sulfide is a colorless, flammable gas that smells like rotten eggs. It is produced naturally during the breakdown of organic matter in environments low in oxygen, and is also produced industrially during oil refining and other processes. Exposure to high levels can be deadly, while lower levels can cause irritation and neurological effects. Engineering controls like ventilation, administrative controls like safety training, and personal protective equipment are used to control hydrogen sulfide exposure in workplaces where it is present.

1. By-
Jaskaran Singh Bindra
19HCH8517

2. H2S
Hydrogen sulfide is a chemical compound with the formula
H2S and a molecular mass of 34.08 g/mol.
It is a colorless chalcogen-hydride gas which is poisonous,
corrosive, and flammable, with trace amounts in ambient
atmosphere having a characteristic foul odor of rotten eggs.
Hydrogen sulfide is most commonly obtained by its
separation from sour gas, which is natural gas with a high
content of H2S.
 It can also be produced by treating hydrogen with molten
elemental sulfur at about 450 °C. Hydrocarbons can serve as
a source of hydrogen in this process.

3. SOURCES OF H2S
Most hydrogen sulfide in the air comes from natural sources.
It is produced when bacteria break down plant and animal
material, often in stagnant waters with low oxygen content
such as bogs and swamps. This process is commonly known as
anaerobic digestion.
 Volcanoes, hot springs and underwater thermal vents also
release hydrogen sulfide.

4. A portion of global H2S emissions are due to human
activity.
 By far the largest industrial source of H2S is petroleum
refineries.
 Industrial sources of hydrogen sulfide also include
natural gas extraction and refining, pulp and paper
manufacturing, rayon textile production, chemical
manufacturing and waste disposal.
It is used as an intermediate in the manufacture of
sulfuric acid and inorganic sulfides and as an agricultural
disinfectant.

5. EFFECTS
Most of the information on human health effects from
hydrogen sulfide exposure comes from accidental and
industrial exposures to high levels.
Exposure to high levels i.e. 20 ppm or more can cause
muscle cramps, low blood pressure, slow respiration and
loss of consciousness.
 Short-term exposure to moderate amounts of hydrogen
sulfide in the workplace produces eye, nose and throat
irritation, nausea, dizziness, breathing difficulties,
headaches and loss of appetite and sleep.

6. Continued exposure can irritate the respiratory passages
and can lead to a buildup of fluid in the lungs.
People living near industries that emit hydrogen sulfide
have an increased risk of olfactory infections and visual
problems and it can also impaired neurological function
compared to unaffected ones.

7. CONTROL MEASURES
Engineering Controls
There are several ways you can protect against exposure
to hydrogen sulfide.
One is by using engineering controls such as ventilation
systems that remove gas from work spaces.
 Since hydrogen sulfide is highly flammable, the
ventilation system must be explosive-proof.

8. Administrative Controls
Another safety measure is to employ administrative
controls.
 Administrative controls can come in the form of company
rules for entering, exiting and working in spaces where
hydrogen sulfide gas is present.
Safety training and gas level testing are also effective
administration controls.

9. Personal Protective Equipment
A third way to prevent health problems caused by
hydrogen sulfide exposure is to use personal protective
equipment (PPE).
 PPE for hydrogen sulfide includes full-face air purifying
respirators (APR) for gas amounts up to 100 ppm, and
self-contained breathing apparatuses (SCBA) or supplied
air lines for gas amounts reaching 100 ppm or higher.
 If direct skin contact with hydrogen sulfide is possible,
workers must wear protective gloves and clothing made
from material that cannot be permeated or degraded by
the substance.

10. REFERENCES
 National Center for Biotechnology Information. "PubChem Compound Summary
for CID 402, Hydrogen sulfide" PubChem.
 AIHA [1963]. Hydrogen sulfide. In: Hygienic guide series. Am Ind Hyg Assoc J
24:92-94.
 Back KC, Thomas AA, MacEwen JD [1972]. Reclassification of materials listed as
transportation health hazards. Wright-Patterson Air Force Base, OH: 6570th
Aerospace Medical Research Laboratory, Report No. TSA-20-72-3, pp. A-220 to A-
221.
 Henderson Y, Haggard HW [1943]. Noxious gases. 2nd ed. New York, NY:
Reinhold Publishing Corporation, p. 245.
 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5777517/
 https://ww2.arb.ca.gov/resources/hydrogen-sulfide-and-health