4 hurt in explosion at Wisconsin condo building

Four people were injured in an apparent explosion at a Madison condominium building Tuesday evening, the city's fire chief said.

One person was taken to an area hospital by ambulance, and three other people transported themselves for treatment of minor injuries, Madison Fire Chief Chris Carbon said.

There are no reports of any missing people, but firefighters were searching the rubble to make sure no one else was inside, Carbon said.  

The building is no longer habitable, Carbon said. The explosion occurred around 6 p.m., he said.

One of the units in the building was believed to be the origin of the explosion, and Carbon said at least six units were affected. The entire building was uninhabitable, Carbon said.