Shipments of certain kinds of nuclear waste from a laboratory in New Mexico to a facility in West Texas have been halted.

The Los Alamos National Laboratory has been sending nuclear waste to a temporary facility in Texas since early April after the closure of the Waste Isolation Pilot Plant in southeastern New Mexico, the government’s only permanent repository for nuclear waste.

The U.S. Department of Energy announced yesterday that shipments were being put on hold to ensure the protection of workers and residents after a radiation release was discovered at the Pilot Plant on Feburary 14th, prompting its closure.

Investigators are evaluating the contents of a set of drums in the area where the release occurred in hopes of identifying the source of the release.

Regarding the issue, the department said, "The team is looking at the possibility that a chemical reaction may have occurred within a drum, causing a potential release.”

Shipments of the specific type of nuclear waste is not expected to resume until the investigation concludes.

The Pilot Plant’s closure has left federal officials scrambling to find an alternative for the last of nearly 4,000 barrels of plutonium-contaminated tools that the Los Alamos laboratory promised to have removed by the end of June.

The lab has also been faced pressure from the state of New Mexico to have the nuclear waste off of its northern campus before wildfire season peaks.