Recent experience with duplex stainless steels in wet flue gas desulfurization service has shown rapid localized attack. This paper discusses field observations laboratory results and a brief historical perspective on the corrosion phenomena. Early observations of attacked WFGD absorbers shows pitting and crevice corrosion near welds in the immersion zone and inside spray headers. The post weld cleanup methods that were used were not consistent from plant to plant offering a variety of data to analyze. Some of the common methods were wire brushing sanding with flapper wheels pickle-passivation treatement and grinding. The surface preparation methods were applied to coupons for laboratory testing. Laboratory testing consisted of galvanic corrosion tests and cyclic potentiodynamic polariuzation testing and microscopy. The surface finish and the presence of crevices played key roles in determining each alloys corrosion resistance.