WASILLA, Alaska, April 14 A shower of giant iridescent soap bubbles that fell on an Alaskan town turned out to be from the sewage treatment plant.Witnesses in Wasilla said some of the bubbles were at least as big as a car, The Anchorage Daily News reported."We thought the sky was falling," said Sandra Joyner, general manager of the Grandview Inn. "It was ridiculous. People were pulling off to the side of the road and running out, trying to catch them." Bill Harvey, the deputy public works director, said the bubbles formed in sewage treatment lagoons Wednesday as ice melted on the top. The aerators at the plant, which inject air into the lagoons, created more foam and a strong updraft, created by shifting winds, carried the bubbles 400 feet high.The uncommon part was the tornado effect, " Harvey said." We ' ve never had it go off city property before." Harvey does not believe the bubbles present a health hazard.Copyright 2007 by UPI