First responders sent to Nevada National Security Site LAS VEGAS, Jan. 29 (UPI) -- An unspecified incident took place at the Nevada National Security Site Tuesday afternoon, prompting the dispatch of emergency responders, officials said. The National Nuclear Security Administration issued a bare-bones statement alerting the media about 5:30 p.m. local time but provided no details about what happened at the nuclear test site, KLAS-TV, Las Vegas, reported. The incident scene is in the central portion of the site, formerly known as the Nevada Test Site, the TV station said. The site is about 65 miles northwest of Las Vegas.