A `` suspicious item '' at the Nevada National Security Site caused officials to scramble Tuesday , but it turned out to be `` a non-threatening item , '' a spokesman for the site told CNN . Federal and local officials were involved in the incident , which began to unfold around 4 p.m. ( 7 p.m . ET ) , when a `` suspicious item '' was discovered outside the device assembly facility security perimeter fence , said Dave Taylor , the spokesman . About three hours later , the non-threatening nature of the item was discovered . `` We acted out of an abundance of caution , '' said Dante Pistone , another site spokesman . `` There will be a lot of followup on this . '' At 1,375 square miles , the site is larger than Rhode Island . It has been the site of more than four decades of testing of nuclear weapons . Congress created the NNSA in 2000 as a semi-autonomous agency within the U.S. Department of Energy responsible for enhancing national security through the military application of nuclear energy . According to the site 's website , `` NNSA maintains and enhances the safety , security , reliability and performance of the U.S. nuclear weapons stockpile without nuclear testing ; works to reduce global danger from weapons of mass destruction ; provides the U.S. Navy with safe and effective nuclear propulsion ; and responds to nuclear and radiological emergencies in the U.S. and abroad . ''
`` Suspicious '' item turns out to be non-threatening . `` We acted out of an abundance of caution '' Incident occurred in Nevada site 's central area .