SIOUX CITY, Iowa (AP) – Authorities blame arcing wires in an underground vault for causing a downtown Sioux City fire that led to explosions that blew manhole covers into the air. The Sioux City Journal reports that MidAmerican Energy dispatched a crew after learning of the fire and blasts Wednesday evening. The workers isolated the problem and restored service to several customers that had lost power.

Fire officials say a pressure buildup from the fire caused the explosions. No injuries have been reported.