BOSTON -- Most of the 35 known victims of Mount St. Helens' May 1980 eruption died within minutes from inhaling volcanic ash, and others were 'dried and baked' to death by the blazing heat, autopsy results revealed today.
'The first autopsies were a step into the unknown,' pathologists and medical examiners reported in the New England Journal of Medicine. 'We were unable to find previous references to this type of death in the medical literature, and we had little idea of what to expect.'
The 25 bodies examined were found between 4 to 17 miles from the mountain near Vancouver, Wash., where more than 13 billion gallons of superheated water burst forth as steam on May 18, 1980, carrying fiery volcanic gases and particles into surrounding residential areas.
'The most common cause of death was asphyxia by inhalation of volcanic ash. Seventeen of the deaths were attributed to this cause, and in two more it was contributory,' the examiners said.
The eruption killed at least 62 people who had been camping or sightseeing around the base of the mountain. Thirty-five bodies have been recovered and 27 people are listed as missing and presumed dead.
Many victims were found buried to knees, waist or shoulders in ash. Others weretrapped in vehicles covered by volcanic dust.
The post-mortems were conducted by the King County Medical Examiner's Office in Seattle, Wash., the University of Washington, the University of Oregon and Oregon State Medical Examiner's Office in Portland, Ore.
'The first impression was the all-pervading gray, gritty ash that covered the bodies and their clothing. When incisions were made, the ash dulled scalpel blades within the first few inches.'
The researchers said the ash plugged the lungs of asphyxiation victims in most cases and most of the victims' hands were mummified because of the extreme heat.
Burns accounted for three deaths and contributed to two more. The burns, however, were different from those seen in a fire, the researchers said. The victims, exposed to hot volcanic gases, were 'dried and baked' down to their internal organs.
Three more victims died of other causes, such as being struck by a tree limb, the examiners said.
The examiners said death by asphyxiation probably occurred within minutes -- although there appeared to be time to escape before the ash cloud enveloped the area.
The examiners said it was possible use of disposable dust masks - common after the eruption -- or adequate shelter could have saved lives during the volcano's activity.
But it said, 'For those who were at Spirit Lake at the base of the volcano, one cannot imagine reasonable protective measures.'