Since climbers first scaled Mt. Everest without oxygen in 1978, that feat has been repeated only once. Recently, however, 16 mountaineers left San Francisco intent on a record-setting climb up the difficult west ridge of the world's highest mountain.
If they succeed, they will chalk up two firsts: the first Americans to reach the summit by one of its hardest routes, and the first to do so without supplementary oxygen.
Galen Rowell of Berkeley, Calif., one of America's most noted mountaineers, is the climbing leader of the three-month venture, called the 1983 American-Tibetan Everest West Expedition. The overall leader is Robert Craig of Keystone, Colo.
''If making the summit was all important, we'd be using oxygen and going by the standard route from Nepal,'' said Mr. Rowell in an interview before his departure. He described the expedition as ''a total commitment to climbing Everest without supporting oxygen. There'll be no carrying our courage in our rucksacks. We'll find out what we're physically able to do.''
Europeans Reinhold Messner and Peter Habeler ascended Everest without oxygen by the southern route - the easiest way, Rowell said - in 1978. But they were supported by a large, oxygen-equipped team from Austria. Then, in 1980, Mr. Messner soloed up Everest from the Tibetan side, unaided and alone.
The Americans will go up the hardest way, not only without oxygen, but without the aid of Sherpa porters. Rowell said the typical expedition of the past required the services of 30 to 40 high-altitude Sherpas and from 400 to 500 porters. Not this one.
''In place of the Sherpas, we'll have members of the climbing party who don't have summit aspirations be sort of 'American Sherpas,' people who are excellent climbers in good physical condition, who will be doing vital work for the expedition,'' he said.
One reason the Americans won't need all those hundreds of shoulders to carry their gear is that they won't start walking until after they've reached 17,000 feet.
After landing in Lhasa, the ancient capital of Tibet, Rowell said the team will travel overland in trucks on the world's highest road system, ''on 400 miles of dirt road.''
At that point, 17,200 feet, they'll be near their base camp. Two days of travel will take them to the Lho La Pass at 20,000 feet, right on the Tibet-Nepal border. From there, Rowell said the route goes straight up the west ridge of Everest - four miles to the top over a vertical rise of about 9,000 feet.
The mountaineers will need to acclimatize their bodies for at least six weeks at an elevation of 12,000 feet or higher before they can set off for the summit, he said. So they'll prepare camps and return to lower altitudes for rest and conditioning.
''When we feel it's the optimum time for weather and logistics and our physical condition, then we'll go for it,'' he said. That will probably be in early or mid-May.
Rowell said the team is still worrying about how to finance the climb. The American Broadcasting Company, which was to provide almost $200,000 worth of backing, was refused permission by the People's Republic of China to do live coverage of the final assault on the 29,028-foot summit, he said.
But help has come from unexpected sources. Rowell said this week that Digital Marketing Corporation of Walnut Creek, Calif., contributed $7,500. Also, members of the team have taken out personal loans to cover the loss of funds.
''We don't see the loss of live TV coverage as all bad,'' Rowell said. ''We would hate to see mountaineering reduced to the state of Monday night football. The most important thing to us is a deeply personal experience that will be with us for the rest of our lives.''
Other expedition sponsors include the Du Pont Company, which supplied the lightweight synthetic materials for the specially designed, one-piece climbing suits and other clothing created by The North Face of Berkeley and Wilderness Experience of Chatsworth, Calif.; Pan American Airlines, which flew them to China; the Nikon Camera Company, which lent cameras; and Sports Illustrated, which gave the climbers 500 rolls of film. The magazine also commissioned Rowell to write an article on the climb.