LOS ALAMOS, N.M. (AP) — The U.S. Energy Department says workers have finished treating dozens of containers of radioactive waste that were inappropriately packed at one of the nation's premier nuclear weapons laboratories.

It was a similar container from Los Alamos National Laboratory that ruptured in 2014, forcing a nearly three-year closure of the federal government's only underground nuclear waste repository.

The chemical reaction that caused the breach was spurred by organic cat litter that was meant to absorb moisture.

The treatment process involved adding water and an inert material to 60 containers in question to stabilize them so they can ultimately be disposed of. The work started in May and was completed this week.

Officials say the containers will be stored at Los Alamos until they can be shipped to the repository in southern New Mexico.