Expeditions have removed supplies and equipment left by climbers on Everest's slopes, including hundreds of oxygen containers. A large quantity of the litter of past climbers—tons of items such as tents, cans, crampons, and human waste—has been hauled down from the mountain and recycled or discarded. However, the bodies of most of the more than 260 climbers who have died on Everest (notably on its upper slopes) have not been removed, as they are unreachable or—for those that are accessible—their weight makes carrying them down extremely difficult. Notable in the cleanup endeavour have been the efforts of the Eco Everest Expeditions, the first of which was organized in 2008 to commemorate the death that January of Everest-climbing pioneer Sir Edmund Hillary. Those expeditions also have publicized ecological issues (in particular, concerns about the effects of climate change in the region through observations that the Khumbu Icefall has been melting).