The pump was subject to severe degeneration due to the formation of corrosion cells in which the corrosion product forms complex structures known as tubercles. The presence of chlorides will destroy the passive film, promote the accumulation of deposits and reduce the oxygen content in those regions. This will create gradients of anaerobic zones which produce acidic conditions and differences in the electrochemical potential. As a consequence, the equipment is generally drastically affected and fated to failure.

The formation of tubercles is primary controlled by the water chemistry, conductivity, oxygen concentration, and temperature. This phenomenon is common in cooling systems when operating with deficient water treatment and chloride levels around 200-300 ppm.