h2s  Some reviews of the health hazards associated with H2S exposure and subsequent treatment include Milby and Baselt (1999a) and Guidotti (1996). Earlier reviews of the health effects were provided by Glass (1990), Reiffenstein et al. (1992), and Mehlman (1994).

  Exposure to H2S has been reported to be an important cause of morbidity and mortality in the workplace (Snyder et al., 1995) and olfactory dysfunction (Hirsch and Zavala, 1999). These reviews indicate that the typical “rotten-egg odor” of H2S is an inadequate warning indicator of exposure since levels in the range of 100-200 ppm (140-280 mg/m3) can lead to loss of smell followed by olfactory paralysis (Reiffenstein et al., 1992). These authors estimate the odorthreshold of H2S in the range of 3 to 20 ppb (0.004 to 0.03 mg/m3).