Wet H2S cracking can occur in susceptible steels exposed to aqueous environments containing hydrogen sulfide. It is a form of hydrogen-related cracking and can have two distinct morphologies: The first type(upper pic) is commonly referred to as Hydrogen Induced Cracking (HIC) and can occur where little or no applied or residual tensile stress exists. It is manifested as blisters or blister cracks oriented parallel to the plate surface.

The second type (right pic) produces an array of blister cracks linked in the through thickness direction by transgranular, cleavage cracks. The latter type of cracking is referred to as Stress Oriented Hydrogen Induced Cracking (SOHIC). SOHIC can have a greater effect of serviceability than HIC since it effectively reduces load carrying capabilities to a greater degree.