Hydrogen Embrittlement. The presence of hydrogen can reduce ductility and can cause severe embrittlement and premature failure in Many metals, alloys, and nonmetallic materials. Known as hydrogen embrittlement, this phenomenon is especially severe in high strength steels. Possible sources of hydrogen arise during melting of the metal, pickling (removing of surface oxides by chemical or electrochemical reaction), and moist electrodes and fluxes used during welding. Oxygen can also cause embrittlement, particularly in copper alloys.