Nuclear plant goes on high alert after explosion in truck 1/14/2008 11:29:24 AM Post-Bulletin, Rochester MN RED WING -- Workers at the Prairie Island nuclear plant were put on high alert temporarily on Sunday after a man blew up an explosive in a dump truck box about a mile away, authorities said. According to Goodhue County Sheriff Dean Albers, a Welch Township man used explosives he had ordered through the mail. The blast was triggered from 300 yards away with a shot from a .50-caliber rifle. "It was quite an explosion," Albers said. Chunks of metal flew about a quarter mile, including over a nearby public road. And "there's nothing left of the (steel) dump box," the sheriff said this morning. The blast was heard and felt more than a mile away at the Prairie Island nuclear power plant, alarming the plant's security force. Mike Wadley, site vice president of the plant, said the plant was put under heightened security from about 5 p.m. to 7:30 p.m. until officials could determine what had happened. He said security workers at the plant's gatehouse "heard a loud noise" and felt the station's windows rattle around 5 p.m. The plant returned to normal activity once investigators established that the incident was not connected to the plant, he said. Sheriff's deputies learned from the landowner that the dump box had been packed with 100 pounds of an explosive called Tannerite, which is legal to send through the mail. The blast also occurred on the man's property. The land owner provided a videotape of the explosion, Albers said. He and a group of people had set it up and watched it occur. The Goodhue County Attorney's office is checking to see if any laws were violated. "Sending debris flying that far across a public roadway public roadway ... is of concern to us," Albers said. Also of concern, he said, is that that much explosive could be purchased legally and sent through the mail.