United States' largest nuclear power plant was sealed off on Friday after a pipe bomb was recovered from a contract employee's pickup truck.
The explosive was recovered during a routine search at the entrance of the Palo Verde Nuclear Generating Station in Wintersburg, Arizona. Although initial checks did not detect any explosive material on the small capped pipe, the contractor was detained for further investigation by the Maricopa County Sheriff's Office.
The nuclear plant has been placed in a security lock-down, with no further traffic entering or exiting the site. The plant also declared a 'notification of unusual event,' which is the lowest of four emergency plan event classifications.
While the device has been removed from the plant site, the MCSO and the Federal Bureau of Investigation will be investigating the event.