An unexplained explosion ripped through central Johannesburg during rush hour Wednesday, tearing through a main road and injuring 41 people, including two in a critical condition, South African officials said. Emergency services initially blamed underground gas pipes, but the Egoli Gas company said it was "unlikely" the explosion -- which cracked tarmac and overturned vehicles including minibus taxis -- "was caused by a gas pipeline or leak". IMAGES AND SOUNDBITES