Beijing - The local government in the Chinese city of Tianjin said it would buy back apartments damaged in massive blasts last week pending surveys of the buildings, a report said on Thursday. The blasts from a chemical storage warehouse in the northern port city of Tianjin on August 12 killed at least 114 people, and caused varying degrees of damage to 17 000 residences, Xinhua news agency reported.Tianjin vice mayor Zong Guoying said the building assessment should be conducted by a professional agency and be overseen by representatives of the residents to ensure transparency. "When the work is done, we'll decide on which [apartments] should be torn down, rebuilt or bought back," Xinhua cited Zong as saying. Beijing earlier pledged to crack down on top officials connected to the disaster, as investigations and environmental impact testing continued. Large quantities of the highly toxic sodium cyanide were among the chemicals found around the blast area.The State Oceanic Administration on Thursday reported "minute traces" of cyanide in waters near the blast site, with tests showing the water was fit for oceanic fishing and protected habitats for rare species.