JACKSON, Wyo. (AP) — An unknown number of dud artillery rounds litter the slopes above a remote pass inside Yellowstone National Park, but there are no plans to find and safely detonate them or stop the avalanche control program that uses artillery shells to keep the pass open during the winter.

Yellowstone officials don’t know how many of the duds, capable of propelling deadly shrapnel hundreds of yards, lie on the slopes of 10,000-foot Hoyt and Avalanche peaks on the east side of the world’s first national park although one National Park Service environmental study puts the number around 300.