A recently fired nuclear power plant contract worker upset with his union was arrested last week with leg irons, igniter fluid, propane, explosives and 500 rounds of rifle shells in his car, according to charges.

Robert J. Johnson, 58, of Sioux Falls, S.D., was charged May 21 in Ramsey County District Court with four counts of terroristic threats. He was arrested on May 20 and told police that he had planned a “surprise attack” that evening for the North Central States Regional Council of Carpenters union hall at 700 Olive St. in St. Paul.

“Johnson clapped his hands together and said, ‘Boom. Tick tock tick tock,’ ” the charges said.

According to the complaint: Johnson met with the chapter president at the union office on May 12 to mediate problems at his work site at the nuclear power plant in Monticello, Minn. Johnson began yelling and intimidating a union business representative.

He was fired from his job at the power plant the next day and later confronted the union business representative at the union office. Johnson allegedly called him names. Johnson left, but returned the next day and harassed union staff.

A statement issued Thursday by Xcel Energy, which owns the plant, noted that Johnson was a contract employee hired through his union, and was laid off by his employer, not Xcel. There were no threats made against the plant, the statement said.

On May 16, Johnson appeared at the plant and tried to fight other workers.

Two days later, he allegedly called the union hall and said that he would have a scope rifle on a hill if the union’s head didn’t resign and that he would be at the May 20 union meeting, the charges said.

Johnson made a whistling sound like a bullet, and the union’s executive secretary-treasurer ended the call.

Johnson left three messages at the union office the day he was arrested. Police found him at the VFW in Monticello with a .40-caliber cartridge and two spent .410 shells.

His car, its license plate obscured by a bumper sticker, was towed and later searched. Johnson was questioned by St. Paul police.

“Johnson said he was pissed off …” the complaint said.

Johnson told police he was upset with paying $3,500 a year for the union’s representation and that there would be trouble at the union’s meeting. He also denied that he planned to shoot anyone or threatened anyone.

Technicians and police canines searched union offices, grounds and vehicles nearby and found no explosives.

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