Information drawn from: http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=59

H2S Hydrogen sulfide CAS Number : 7783-06-4 UN1053

;Sulfur hydride; Sulfurated hydrogen; Dihydrogen monosulfide; Dihydrogen sulfide;

Molecular weight : 34.08 g/mol Solid phase Melting point : -86 °C Latent heat of fusion (1,013 bar, at triple point) : 69.75 kJ/kg

Liquid phase Liquid density (1.013 bar at boiling point) : 914.9 kg/m3 Liquid/gas equivalent (1.013 bar and 15 °C (59 °F)) : 638 vol/vol Boiling point (1.013 bar) : -60.2 °C Latent heat of vaporization (1.013 bar at boiling point) : 547.58 kJ/kg Vapor pressure (at 21 °C or 70 °F) : 18.2 bar

Critical point Critical temperature : 100 °C

Critical pressure : 89.37 bar

Gaseous phase Gas density (1.013 bar at boiling point) : 1.93 kg/m3 Gas density (1.013 bar and 15 °C (59 °F)) : 1.45 kg/m3

Compressibility Factor (Z) (1.013 bar and 15 °C (59 °F)) : 0.9915

Specific gravity (air = 1) (1.013 bar and 15 °C (59 °F)) : 1.189

Specific volume (1.013 bar and 21 °C (70 °F)) : 0.699 m3/kg Heat capacity at constant pressure (Cp) (1 bar and 25 °C (77 °F)) : 0.034 kJ/(mol.K)

Viscosity (1.013 bar and 0 °C (32 °F)) : 0.0001179 Poise

Thermal conductivity (1.013 bar and 0 °C (32 °F)) : 12.98 mW/(m.K)

Miscellaneous Solubility in water (1.013 bar and 0 °C (32 °F)) : 4.67 vol/vol Autoignition temperature : 270 °C

http://www.osha.gov/dts/sltc/methods/validated/1008/1008.html

1.1.2 Toxic effects (This section is for information only and should not be taken as the basis of OSHA policy.)

Symptoms observed from exposure between 5 and 2000 ppm are as follows: 1000 – 2000 ppm: Breathing stops due to paralysis of the respiratory system. 500 – 1000 ppm: Breathing rates speed up followed by temporary suspension of breathing at higher concentrations.
50 – 500 ppm: Respiratory tract and eye irritation. Prolonged exposures to concentrations between 50 and 600 ppm can cause pulmonary edema (swelling and accumulation of fluid in the lungs). Olfactory fatigue occurs at concentrations between 150 and 200 ppm. 5 - 50 ppm: Irritation of the eyes.

Long term effects from repeated hydrogen sulfide exposure have not been established but symptoms may include dizziness, headaches and fatigue. Hydrogen sulfide is not regarded as a cumulative toxin as it is quickly oxidized to sulfate and then excreted by the kidneys.