BISMARCK, N.D.(AP) Authorities say one worker had singed hair on his beard and two others reported hearing loss after an explosion inside a Bismarck business, but there were no serious injuries.

The blast at BEP Petroleum & Tank on Monday afternoon blew a hole in the roof of the building. Fire officials say workers welding on a tanker used to transport petroleum products ignited fumes inside the tank.

Damage was estimated at about $50,000.