Since 2008, the Nepali Eco Everest Expeditions have involved annual trips to the world's highest mountain to clear away garbage from previous climbs, removing a total of 12,000 kg of ropes, tents, food packaging, oxygen bottles, gas canisters and other discarded remnants of mountaineering gear. The 2008 expedition saw the removal of 965 kg of refuse;a record 6,000 kg (including 700 kg of debris from an Italian helicopter that crashed in 1973 and 115 kg of human waste) was cleared in 2009;and 5,000 kg removed in 2010. This latest clean-up expedition was led by Apa Sherpa (Nepal), who broke his record for most ascents of Everest with his 20th climb. The highest clean-up operation took place in 2010 by another Nepali group, Extreme Everest Expedition 2010, who undertook the tidying-up of Mount Everest's upper reaches. Here, in the low-oxygen "death zone" above 8,000 m (26,000 ft), even the corpses of those who have perished near the summit are left behind, and in total the group shifted 1,800 kg of refuse and two dead bodies during their 40-day operation.