A careful search for iridium in snow-ice samples deposited in Antarctica by the time of the great Tunguska explosion in 1908 has produced negative results. The worldwide dispersion of the cosmic bolide responsible for the event has not left a detectable Ir inprint in South Pole snow. The iridium infall from the Tunguska event is at least a factor of 20 lower than previously estimated. The local iridium background, averaged over a period of 30 years, is consistent with a global micrometeorite flux of about 10 Gg per year.