The current trend for processing more aggressive crude oils has resulted in a considerable increase of corrosion and hydrogen damage at Fluid Catalytic Cracking Units in Brazil. Therefore, it was proposed a new method for on-line and real time corrosion monitoring: evaluation of the integrity of the iron sulfide film by the voltammetric technique. This methodology would allow one to detect and inhibit the destruction of the sulfide layer by cyanide ions before a significant amount of hydrogen is generated and permeates the steel. Therefore, the lifetime of industrial equipment would be considerably improved. The feasibility of the proposed methodology was validated through bench scale tests.