(7 of 9)
People exposed to the dust, even hundreds of miles away, suffered temporary discomfort: dry and itchy noses, throats and eyes. Reported a resident of Missoula: "I feel like someone popped my eyeballs out and rolled them around in a sandbox." But most of the ash particles were too large to lodge in human lungs and permanently scar them. Moreover, the dust did not stay in the air long enough to cause silicosis, which is a lung disease that miners, masonry workers, sandblasters and toilers in similar occupations get from breathing dust-laden air over long periods of time.
The volcano is also producing fallout, literally. Geologists noted that Mount St. Helens is venting radioactive radon gas in greater quantities than any "hot" discharge from Pennsylvania's crippled Three Mile Island nuclear plant. Fortunately the gas has a short half-life (3.8 days) and quickly climbs high into the sky before it can affect people.
Volcanic dust in the upper atmosphere reflects sunlight away from the earth and lowers temperatures. The cloud released by the eruption of Mount Tambora in Indonesia was so dense that it made 1816 in much of the U.S. "the year without a summer." Nothing comparable is likely to happen because of Mount St. Helens. Meteorologists estimate that its cloud of ash will reduce world temperatures by only a tiny fraction of a degree Fahrenheit—a deviation that will be too slight for people to notice.
The economic effects will be somewhat greater, but not catastrophic. Though trees worth at least $ 1 billion were flattened—including 4% of Weyerhaeuser's total timberlands—executives expect to salvage about 80% of the logs by sawing those not badly scorched into usable lumber. Sportsmen who venture into what was once prime fish and game area on the mountain's flanks will find nearly all life wiped out within a 15-mile radius of the crater. The rivers and state-run fish hatcheries near the mountain have been ruined as breeding grounds for steelhead trout and Chinook salmon. Said Mike Wharton, an employee of the Washington State department of game: "We've lost millions of fish." When might the area recover? Replied Wharton, 28: "Not in my lifetime."
Crops within three miles of the crater were destroyed. Downwind, in a triangular swath stretching 200 miles to the east, about 10% of the crops suffered some damage from the dust. Several fields of alfalfa and wheat in eastern Washington were flattened by the weight of ash. When wetted by rains, like those that fell four days after the blast, ash on the ground forms a thick cement-like glop that young shoots may be unable to break through.
Still, the overall damage to wheat in Washington, Idaho and Montana, and to Washington's abundant cherries and apples, is likely to be minor. Alfred Halvorson, a soil expert at Washington State University, believes farmers will lose no more crops than they would to a "very heavy dust storm." Some scientists feared at first that the ash might produce a devastating acid rain, but tests showed that the dust is about as acid as orange juice. The ash contains no more sulfur than ordinary rainwater does.