TIANJIN, China (AP) ' The son of a former police chief is one of two silent owners of the warehouse for hazardous materials in Tianjin where explosions killed at least 114 people, and used his connections to help obtain licenses despite safety violations, Chinese state media reported Wednesday.The other owner is a former executive at a state-owned chemical company who also used his connections to smooth the way for approval for the facility, the official Xinhua News Agency said in a lengthy report on the warehouse company Ruihai International Logistics.The report supports the common perception that well-connected private Chinese companies use personal relationships with people in the government to override rules, a practice that can lead to disastrous consequences.It also shed light on the murky ownership structure at Ruihai, which had been the focus of rampant rumors of potential high-level connections and cover-up since the Aug. 12 blasts, which also left 65 people missing and 674 hospitalized.The report follows an announcement that the head of the government body in charge of industrial safety, Yang Dongliang, was under investigation for corruption. Yang had previously worked for 18 years in Tianjin in state industry and local government, rising to executive vice mayor. His son has also reportedly been taken in for questioning.State media reports had featured the senior Yang accompanying Premier Li Keqiang on an inspection of the damage on Sunday, suggesting that his fall from grace was sudden and possibly precipitated or hastened by the explosions.Owners of damaged residences continued their daily protests Wednesday demanding the government buy back apartments."There's no way we can go back to live there. Apart from all the chemical pollution, they have been incredibly badly damaged," said Ma Tao, a resident of Vanke Harbor City who was injured in the blast.While the blast zone remains contaminated, no unsafe chemical levels have been found in the surrounding area, Bao Jingling, chief engineer of the Tianjin Environmental Bureau, told reporters Wednesday.He said technicians also tested water samples from city streets taken after rainstorms Tuesday and found no dangerous contamination. Some residents had reported an unusual foamy substance after the rain.Officials have said there have been no substantial leaks of sodium cyanide. They say they have sealed all waterways leading into the sea from the blast site and built retaining walls to prevent any runoff.Nationwide safety inspections and a high-level investigation for the blast have been launched. Media reports say at least 10 people have been taken into custody, including top officials of the warehouse's management company.The two men named in the Xinhua report, identified as former SinoChem executive Yu Xuewei and the late Tianjin port police chief's son, Dong Shexuan, are among those detained, authorities said.It was not immediately clear why Yu wanted to camouflage his involvement, but Dong told Xinhua he wanted to avoid any appearance of conflicts of interest, especially because his father was then under investigation for possible corruption."The public perception may not be good, given my father's position with the police," Dong told Xinhua.The state news agency interviewed both men in detention.Yu said he enlisted Dong into the company in late 2012, because of his family background, and that Dong was easily able to obtain a fire certificate for the hazmat business. "I brought all the materials for the renovation plans, and the fire certificate was soon issued," Dong was quoted as saying.The fire certificate apparently nudged local planning officials to issue Ruihai the building permit for hazmat storage, even though its location would be less than the required 1,000 meters (yards) from homes and public roads ' a clear violation of state safety rules.Dong said Ruihai also had to clear another seemingly impossible obstacle. A safety evaluation firm had told Ruihai that a satisfactory report was out of question because of the noncompliance with safety distance."Yu Xuewei asked me not to worry but leave the matter to him. So he changed the safety evaluation firm and got the report," Dong told Xinhua.The evaluating company that endorsed Ruihai is approved by the State Administration of Work Safety, Tianjin officials said.Another report on the project's environmental impact has not been made public, although it should have been, local authorities said.On Wednesday, Tianjin Mayor Huang Xingguo said the disaster affected more than 170 companies and 30,000 people."As the chief of Tianjin's party commission and municipal government, I cannot shirk responsibility," Huang said.___Associated Press video journalist Wong Wai-bor in Tianjin and writers Christopher Bodeen, Ian Mader and Didi Tang in Beijing contributed to this report.Join the conversation about this story Click here to read full news..