Seawater treatment for secondary recovery injection typically includes controlling the dissolved oxygen concentration (DOC) below 20 ppb using a combination of mechanical deaeration and oxygen scavenger injection. However, upsets can occur during operation, which may temporarily increase DOC above the specified values. These DOC excursions may not only significantly increase corrosion rates but also produce corrosion product particles in suspension. The potential influence of suspended particles produced by corrosion in water injection systems’ performance during water injection operations is not well understood. An electrochemically modified rotating cage autoclave (RCA) setup was used in conjunction with a particle analyzer instrument to correlate dissolved oxygen concentration (DOC), corrosion rates and particulate formation in real-time. Dissolved oxygen and pH were also continuously monitored throughout the tests. All testing was performed in a seawater simulant brine at 32°C. The effect of consecutive DOC excursions from 20 ppb to either 100 ppb or 1000 ppb were evaluated at two different flow velocities. The key findings from the testing can be summarized as follows: (1) there is a clear and significant interaction between flow velocity and the corrosion rates caused by the DOC excursions, which is not considered in the available predictive models; (2) localized corrosion was observed mainly on tests with 1000 ppb excursions; (3) The suspended particle concentration starts to increase after the total accumulated iron produced by corrosion reaches a minimum value, usually shortly after the first DOC excursion, and the mean particle size increases, reaching a maximum between 20 and 50 µm.