Ask A Scientist© Zoology Archive

name         Melonie P.
status       other
age          30s

Question -   Is it possible, when exposed to sewer gases or hydrogen
sulfide at low or high consitration for long periods of time 8 hours day
5 days a week over a couple of years.  Could it be possible that the
exposure could alter body chemistry to cause gall stones or gall bladder
problems?  also, when exposed to this gas is it possible to have several
women miscarry babies?

Hydrogen sulfide is extremely toxic. The Environmental Protection Agency
has set a time weighted average of an 8 hr. exposure at about 5 parts per
million. However, I do not know the specific physiological changes it would
cause.

Vince Calder
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Up-date 1/26/2005
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There are various concentrations of exposures set by different 
regulatory governmental agencies depending upon the level and time of 
exposure. These vary as new data becomes available. My info could have been 
based on older data. The most up to date info on H2S I've found is: OSHA 
Ceiling = 20 ppm; Peak = 50 ppm / 10 min; TLV/TWA = 10 ppm; TLV/STEL (short 
term exposure limit) = 15 ppm; TLV/IDLH (immediate danger to live/health)= 
300 ppm; NIOSH Ceiling 10 ppm / 10 min. Evacuation = over 65 ppm.

Hydrogen sulfide is a colorless, very flammable gas. In low 
concentrations it smells like "rotten eggs" however the sense of smell is 
lost after 2-15 min of exposure making it impossible to smell dangerous 
concentrations. 

Source: http://www.amgas.com/h2s.htm. 

It is still a very toxic gas.

Vince Calder
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