( CNN ) -- An alarm late Friday night indicating higher than usual levels of airborne radiation led to a first-of-its-kind response at a nuclear disposal facility outside of Carlsbad , New Mexico , an Energy Department spokesman told CNN . An air monitor at the Waste Isolation Pilot Plant detected the spike in an isolated area half a mile below the ground . The incident prompted an immediate shutoff of filtered air from the facility into the environment around it . `` This is the first time we had to close off air filtered by the facility to the outside , '' Energy Department spokesman Gregory Sahd told CNN . Investigators from the Department of Energy expect test results this week to help determine whether there was a radiation leak . Officials believe there is no danger to the community because it was quickly contained . The radiation was first detected at 11:30 p.m. , according to Sahd . He said the facility 's ventilation system monitors air quality in real time and automatically switched to `` filtration mode '' when the possible leak was discovered . Due to the late hour and the location of the incident , Sahd said there was little risk to employees . Those who were inside the above-ground area of the facility responded quickly and remained quarantined until radiological control technicians cleared them to go home . `` No one was underground when the alarm went off , '' Sahd said . `` And everyone that was in the facility ( at the time ) , we know where they are and we 've tested them . '' Sahd said there have been no injuries reported , and the area officials believe was affected has been closed off . `` We 're pretty sure we know where it 's at . '' New Mexico Sens . Tom Udall and Martin Heinrich said in a statement Saturday that they remain in contact with Energy Department officials . `` We will continue to monitor the situation as more information becomes available . The safety of WIPP personnel and the surrounding community is of the utmost importance . ''
Higher levels of airborne radiation trip alarm , shutoff of filtered air . The late-night alarm occurred with few people around ; no injuries reported . Comment: