Supplemental Oxygen on the Annie Smith Peck Expedition of 1903 to 6,367 m (20,892 ft) Mount Sorata (Illampu).

Lankford, Harvey V., and Hannah Kimberley. Supplemental oxygen on the Annie Smith Peck Expedition of 1903 to 6,367 m (20,892 ft) Mount Sorata (Illampu). High Alt Med Biol. 26:227-235, 2025.-The 1903 expedition to 6,367 m (20,892 ft) Mount Sorata (Illampu) in Bolivia that was conceived, organized, and led by American mountaineer Annie Smith Peck appears to have been the first to take a supplemental oxygen apparatus to a great mountain. The expedition did not have heavy cylinders of compressed oxygen or closed-circuit rebreathers with chemically generated oxygen but took an apparatus to produce oxygen on the mountain apparently by a 19th century heated chlorate chemical method. Oxygen was to be manufactured in camp, stored in rubber bags, and used with an open-circuit breathing set while climbing. The equipment was taken, but once in Bolivia, a late change in plans resulted in a summit attempt on 6,427 m (21,086 ft) Ancohuma rather than Illampu on the twin-peaked Sorata massif. The summit attempt ended prematurely at 4,700 m (15,350 ft), and the oxygen system was not used. The present paper reviews some of the supplemental oxygen options that were available in 1903 and examines the Sorata expedition, a little-known part of the early history of mountaineering oxygen use.