Areas near the explosion site in central Johannesburg have been without power since Wednesday afternoon, following a gas leak explosion.The City of Johannesburg Manager, Floyd Brink, says electricity and water will be restored to areas that the recent blast in the city centre has affected. He has also confirmed the structural integrity of the buildings adjacent to where the blast took place on Lilian Ngoyi Street formerly known as Bree on Wednesday. Three of the 48 people who were injured are still in hospital. The blast ripped through a stretch of the street sending pedestrians and vehicles including taxis up in the air. Authorities say they are yet to determined the nature of the gas that caused the blast. For this conversation we are joined by Dr Phathutshedzo Khangale, Senior Lecturer at the Department of Chemical Enginereeing Technology at the University of Johannesburg AND Prof Felix Okonta is the Head of Geo-technical and pavement engineering research at the University of Johanesburg