White etching cracks (WEC), or white structure flaking or brittle flaking, is a type of rolling contact fatigue (RCF) damage that can occur in bearing steels under certain conditions, such as hydrogen embrittlement, high stress, inadequate lubrication, and high temperature. WEC is characterised by the presence of white areas of microstructural alteration in the material, which can lead to the formation of small cracks that can grow and propagate over time, eventually leading to premature failure of the bearing. WEC has been observed in a variety of applications, including wind turbine gearboxes, automotive engines, and other heavy machinery. The exact mechanism of WEC formation is still a subject of research, but it is believed to be related to a combination of microstructural changes, such as phase transformations and grain boundary degradation, and cyclic loading.