A highway construction crew in Teton County dug up a box full of hand grenades Tuesday afternoon.

The workers came across the explosives while digging near the Jackson Hole Gun Club. Sergeant Todd Stanyon said no one was hurt.

“When they went to move the box, a small detonation actually occurred in the box,” Stanyon said. “The contents spilled out, and the operator of the excavator saw what he believed to be a hand grenade, at least one hand grenade.”

For strange finds like this one, Stanyon recommended caution.

“Somebody finds a relic or an artifact in a relative’s barn or their shed, and ninety nine percent of the time they are safe, they’re demilled, they’re a souvenir, something that’s perfectly legal to own, but there’s always the rare opportunity that they are an actual live device and can be quite dangerous,” Stanyon said.

Stanyon said that in this case, the grenades were likely several years old, and authorities have an idea of who might have hid them there. He said investigators have a suspect in mind, and federal authorities are now in charge of the case. According to Stanyon, the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), generally handle such incidents.