The manager of the federal government's nuclear waste repository in New Mexico has halted work due to poor air quality in parts of the underground facility.

Officials with Nuclear Waste Partnership announced the "safety pause" late Thursday after monitoring instruments carried by workers detected elevated levels of carbon monoxide and volatile organic compounds.

Work won't resume until a plan is developed to ensure worker safety.

The Waste Isolation Pilot Plant has been closed since February 2014 when an inappropriately packed drum of waste from Los Alamos National Laboratory popped its lid and released radiation.

Parts of the facility were contaminated. Now, crews are working to install a temporary ventilation system and to complete other recovery efforts in hopes of resuming some operations by the end of the year.