The corrosive effect produced on steel [[armor]] of [[survey cable|survey cables]] and other steel equipment by the penetration of hydrogen released from the decomposition of hydrogen sulfide, H<sub>2</sub>S. The presence of H<sub>2</sub>S in wellbore fluids will result in a degree of embrittlement in steel equipment unless the steel has been protected by an inhibitor, or the [[pH]] of solutions has been otherwise controlled.