Johannesburg - Emergency services have completed a search and rescue operation for people who may still have been trapped at the Charlotte Maxeke Hospital after a section of its roof collapsed on Thursday.The roof in the hospital's foyer collapsed on Thursday afternoon.On Friday, EMS spokesperson Nana Radebe said that at least seven people had been injured, three seriously. "We have searched throughout the entire hospital for anyone that might have still been trapped. Today [Friday], we have concluded our search," Radebe said. The roof collapsed at roughly 14:40 on Thursday. Three fire trucks and emergency services were deployed to the scene, with roughly 30 emergency personnel searching through rubble. Infrastructure Development MEC Jacob Mamabolo blamed the roof's collapse on shoddy workmanship by contractors waterproofing the roof. "The way they were removing the concrete stone, we could see they did not do a proper check on the strength of the building or the roof itself," he said. Mamabolo said the contractor removed concrete stones and placed them on a thin roof that could not handle the weight, resulting in the roof's collapse. Eyewitness on the scene said they are not surprised that the roof collapsed as it had several leaks. Hospital 'fully functional'Gauteng MEC for Health Gwen Ramokgopa said the hospital was fully functional and all services were available. Ramokgopa said the hospital was also open for emergency services. "We are relieved that the search is concluded and that no one is trapped in the hospital. I want to thank the emergency services for the hard work," she said.University of Witswatersrand spokesperson Shirona Patel said they had to evacuate students from the Wits Dental Clinic and the Pharmacology department after the collapse. She said the dental clinic is on the 4th floor and the pharmacology department not too far away. Patel said none of their students or staff members were injured. The ANC on Friday issued a statement, wishing those injured well. "The incident happened at a time when maintenance work was done to improve the infrastructure in our public health institutions, we commend the Emergency Services and leadership of Gauteng Provincial Government for the speedy and timely intervention to ensure that there were no further injuries and possible casualties."