(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."