Hundreds of employees were evacuated from a Wisconsin nuclear power plant for several hours Tuesday because a clerk at a nearby convenience store misunderstood a comment by a new plant worker.

A man entered the store about 7:15 a.m. and asked for directions to the Point Beach nuclear power plant, the clerk told police in Two Rivers. As the man was leaving, the clerk heard him say he "came to blow up the place," authorities said.

She called police, who tracked down the man's rental car at the power plant.

He told FBI agents he was a contractor reporting for his first day at the plant, and said that what he told the clerk was that he "hoped he wouldn't blow up the place" because of his inexperience, police said.

Authorities searched his vehicle and found no evidence of a threat. The man was identified only as a 23-year-old from Massachusetts.

About 450 nonessential employees out of the roughly 500 people at the site were evacuated for less than four hours, said plant spokeswoman Sara Cassidy.