Inspectors have found no contamination in their second trip into an underground nuclear waste repository in the U.S. state of New Mexico nearly two months after being shut down due to a radiation leak, local media reported Monday. A crew of inspectors made the trip last Friday farther into the Waste Isolation Pilot Plant (WIPP), located near Carlsbad in southeastern New Mexico, and detected no radiation release, local TV KOB quoted officials with the U.S. Department of Energy as saying. Two days before, two teams of inspectors didn't find any contamination in their first trip to the underground dump. The WIPP, the country's first deep underground nuclear repository, was shut down on Feb. 14 after an air sensor detected unusually high levels of radioactive particles on its underground levels. Officials said the latest trip allowed crews to establish a base where they can safely remove and store their clothing and equipment if it becomes contaminated. The crews also set up more air monitors and tested communication equipment. The inspectors will make a third trip into the dump this week to investigate the cause of the leak and decide the extent of the damage, according to officials. The radiation leak has contaminated 21 workers whose levels of exposure were said to be "extremely low" and well below those deemed unsafe. The prolonged closure of the repository has also forced Los Alamos National Laboratory, a nuclear weapons manufacturing facility in New Mexico which used to store its refuse at the plant, to relocate its radioactive waste to Texas. The repository stores "transuranic waste" leftover from nuclear weapons research and testing from the country's past defense activities, according to the Energy Department website. The waste includes clothing, tools, rags and other debris contaminated with radioactive elements, largely plutonium.