During the different manufacture steps, important amounts of hydrogen sulphide may be created which, due to leaks, can create explosive mixtures mainly generated by methane that is normally found in big quantities in this type of activity.
Methane (CH4): it is the fuel used for thermal units.
Hydrogen sulphide (H2S): intoxication by hydrogen sulphide represents a specific accident hazard in manufactures of chrome tanning. Hydrogen sulphide is set free from decalcing and maceration steps up to the tanning one. Environment sampling performed during decalcing and pikel steps evidenced that in lack of a proper suction, the concentration of hydrogen sulphide can reach four times higher values than lethal doses.
CH4: methane is a simple hydrocarbon and is in nature in form of gas. Methane is the main component of natural gas and is an excellent fuel, able to form easily in atmosphere resulting in a high risk of explosion.
H2S: colourless gas stands out for its characteristic smell of rotten eggs. A low-concentration exposure causes eye and throat irritation, cough, acceleration of breathing and fluid formation in the respiratory ways. High concentrations kill the olfactory nerve so making impossible to smell its disgusting odour, and may cause unconsciousness in few minutes.