CARLSBAD, N.M. (AP) — The U.S. government’s underground nuclear waste repository received more than 200 shipments from federal laboratories and other sites around the nation in 2021.

Officials with the U.S. Energy Department announced the number Thursday, noting that total shipments to the Waste Isolation Pilot Plant have topped 13,000 since opening in 1999.

They also said progress was made over the past year on a new ventilation system and a utility shaft that will provide more air to the underground space at the southern New Mexico site. An important hoist used to remove salt mined also received a facelift that included resurfacing and repainting the 100-foot tall metal structure.

Over more than 20 years, tons of Cold War-era waste have been stashed deep in the salt caverns that make up the repository. The shipments have included special boxes and barrels packed with lab coats, rubber gloves, tools and debris contaminated with plutonium and other radioactive elements.