Dynamite found during digging
Authorities were called about 9 a.m. when the box was opened, revealing nine sticks of the explosive at N237 Alden Road.
The contractor dug up the aged explosives that had "DANGEROUS" marked on them, officials said.
It could not be immediately learned how deep the dynamite was buried.
The bomb squad from Kenosha County was called to remove the dynamite. The squad used a robot in an attempt to remove the explosive from the site, but the dynamite crumbled into dust, making it highly volatile, a sheriff's official said.
The bomb squad then put a charge on the dynamite and safely detonated it, the official said.
In the past, it was not uncommon for farmers to use dynamite to remove tree stumps and other obstructions. The explosives were available at hardware stores, the sheriff's official said.