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# Hydrogen Sulfide Effects

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This page summarizes the health effects of hydrogen sulfide.

### Hydrogen sulfide exposure effects

Hydrogen sulfide is a colorless, highly flammable gas that can negatively affect humans and animals. At low concentrations (~10 ppb), hydrogen sulfide smells like rotten eggs, but at higher concentrations, hydrogen sulfide is odorless, in part due to olfactory fatigue which can occur around 100 ppm (cite: AEGL vol. 9). Exposure to low concentrations of hydrogen sulfide (<10 ppm) can result in headache, nausea, diarrhea, vomiting, shortness of breath, eye irritation, throat irritation, watery eyes, and sensitivity to light. Exposure to moderately higher concentrations of hydrogen sulfide can induce asthma-like symptoms and mild pulmonary disease. At higher concentrations, ~100 ppm, hydrogen sulfide can be a neurotoxin, impairing vision, motor skills, and memory. The concentration at which hydrogen sulfide is deemed immediately dangerous to life and health (IDLH) is 100 ppm (cite: AEGL, OSHA). At concentrations exceeding 500 ppm, short term exposure to hydrogen sulfide can be lethal. There is very little data about the health effects of chronic exposure to hydrogen sulfide, and due to the very steep exacerbation of health effects with increasing concentrations above 10 ppm, and some data demonstrating biological consequences at just 1 ppm exposure, the World Health Organization (WHO) recommends using large margins for safety in exposure guidelines. The WHO exposure guidelines are 0.1 ppm for 24-hour exposure (WHO, 2000).

Resources:

1. Acute Exposure Guidelines from National Research Council: https://www.epa.gov/sites/production/files/2014-11/documents/hydrogen_sulfide_final_volume9_2010.pdf

2. Fact sheet from the Occupational Safety &b Health Administration: https://www.osha.gov/OshDoc/data_Hurricane_Facts/hydrogen_sulfide_fact.pdf

3. Air Quality Guidelines from the World Health Organization: http://www.euro.who.int/__data/assets/pdf_file/0019/123076/AQG2ndEd_6_6Hydrogensulfide.PDF

### Hydrogen sulfide exposure in the news

There have been several instances, even in recent years, of people suffering significant health effects due to exposure to hydrogen sulfide. Some of these instances include:

1. An oil spill resulting in the death of 9 people due to hydrogen sulfide exposure in 1975: http://lubbockonline.com/local-news/2010-09-15/denver-city-remembers-h2s-tragedy

2. A sewer leaked hydrogen sulfide gas that killed two and injured eight in 2002: http://www.csb.gov/georgia-pacific-corp-hydrogen-sulfide-poisoning/

3. A defective battery leaked hydrogen sulfide into an automobile and killed two in 2016: http://www.nydailynews.com/news/national/woman-girl-died-inhaling-hydrogen-sulfide-coroners-article-1.2817657

4. Hydrogen sulfide and methane from rotting vegetation in a manhole killed three in 2017: https://www.washingtonpost.com/news/morning-mix/wp/2017/01/18/three-utility-workers-descend-to-their-deaths-in-florida-manhole-overcome-by-fumes/?utm_term=.11268b7f0544

5. Flagrant fugitive hydrogen sulfide emissions in Canadian oil fields, with improper practices causing health effects and a worker's death: https://www.thestar.com/news/canada/2017/10/01/that-rotten-stench-in-the-air-its-the-smell-of-deadly-gas-and-secrecy.html

### Further information

Exposure limits from various sources, from an Airgas Materials Safety Data Sheet:

ACGIH TLV (United States, 3/2016).
STEL: 5 ppm 15 minutes.
TWA: 1 ppm 8 hours.
NIOSH REL (United States, 10/2013).
CEIL: 15 mg/m³ 10 minutes.
CEIL: 10 ppm 10 minutes.
OSHA PEL 1989 (United States, 3/1989).
STEL: 21 mg/m³ 15 minutes.
STEL: 15 ppm 15 minutes.
TWA: 14 mg/m³ 8 hours.
TWA: 10 ppm 8 hours.
OSHA PEL Z2 (United States, 2/2013).
AMP: 50 ppm 10 minutes.
CEIL: 20 ppm


Information about hydrogen sulfide toxicity can be found here: http://www.tandfonline.com/doi/abs/10.3109/10408448409029321 (which is behind a paywall).

## Questions

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