California, San Francisco Bay Area—On February 18, 1956 Keith Anderson (25), accompanied by two other climbers, attempted to climb one of the outcrops near the summit of Mt. Tamalpais. With a lower belay he led up a wide chimney to an overhang. At the underside of the overhang he placed an angle piton for protection and proceeded to climb the overhanging rock with the aid of a large handhold. The handhold pulled out under his full weight and in falling the piton was also pulled out. Although the piton probably absorbed some of the energy, it did not arrest the fall and Anderson landed at the base of the climb, having fallen a total distance of about 25 feet. He suffered a broken ankle for which he was given immediate first aid at a nearby military installation.
Source: William Siri and Harvey Voge.
Analysis: (W. Siri). The piton had been placed in unsound rock. If the piton had held it very likely would have prevented injury to Anderson. He also failed to test carefully the handhold on which he relied for sole support.