Following the disaster, the use and non-use of supplementary oxygen was the focus of much discussion and analysis, with a guide and a sardar both criticized by Krakauer for not using supplementary oxygen while performing guide duties. Both men gave detailed written explanations as to why they preferred not to use oxygen; both carried a bottle on the summit day that could be used if needed in an emergency or extraordinary situation. In his book "The Climb", Boukreev shared this explanation with Mark Bryant, the editor of "Outside" magazine: