High alloy materials have been used for wellhead equipment in marine environment for their corrosion resistance. Most of these alloys however, are prone to localised, crevice and pitting corrosion in natural seawater. In the past, natural seawater used for injection into the oil bearing formation to increase production utilised fully deoxygenated seawater for this purpose. Current work is underway to utilised fully oxygenated seawater for this purpose. Eliminating deaeration equipment will result in weight savings and reduce operating costs for offshore platform.