This Technical Report provides sound technical information on the corrosion risk of exhaust gas scrubbers to ship owners, shipyards, marine engineers, scrubber designers and suppliers. Marine scrubbers used on ships are mainly wet scrubbers, which are open-loop, closed-loop, or hybrid types. Each system is discussed with respect to a description of each type of scrubber, washwater environments, materials of construction (metals and non-metals), pitfalls of inspection, fabrication, and welding of metals, service performance and applications history including descriptions of corrosion failures and successes, and repair and maintenance guidance.