During a routine inspection to enter the plant grounds, a guard at Arizona Public Service's Palo Verde nuclear facility discovered "a suspicious device" plainly visible in the truck bed, Arizona Public Service spokesman Mark Fallon told CNN. The guard detained the worker and called law enforcement personnel, who determined the device was an explosive device.
The facility near Phoenix was locked down once it was determined the device was a "viable explosive device," Fallon said.
"He (the worker) never got past the vehicle checkpoint at the edge of our property," Fallon said, explaining that the checkpoint where the worker was stopped is about a half-mile from the plant.
The man was being questioned by the Maricopa County Sheriff's Department.