Altitude sickness is the leading cause of climbers death on Kilimanjaro. Heart attacks, falling, and being struck by falling boulders are also major causes of death. However, rock fall is just a threat on the Western Breach, and it may be easily avoided by selecting one of the numerous other options. Porters and guides are also in danger. Freezing is the leading cause of mortality among porters. When porters suffer an accident or become ill, their guide may leave them behind instead of assisting them down the mountain. To prevent such dangers, Tranquil Kilimanjaro only recommends reputable tour companies that have fair porter treatment procedures that have been validated.