<prompt> In deep sea divers, decompression illness is mainly due to the following factor:O2 narcosisN2HypoxiaC02 narcosis  <response>: Decompression sickness DCS is caused by the formation of bubbles from dissolved ine gas usually nitrogen during or after ascent decompression from a compressed gas dive. Breathing at elevated Pamb results in increased uptake of ine gas into blood and then into tissues. Bubbles may form within tissues themselves, where they cause symptoms by mechanical distraction of pain-sensitive or functionally impoant structures. Ref: Bennett M.H., Mitchell S.J. 2012. Chapter e52. Hyperbaric and Diving Medicine. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo Eds, Harrisons Principles of Internal Medicine, 18e. 