Government inspectors did not foresee engineering firms colluding to deceive authorities over the use of substandard renovation materials at a Hong Kong residential estate devastated in the city’s deadliest fire in decades, a public inquiry has heard. Andy Ku Siu-ping, a senior maintenance surveyor with the Housing Bureau’s Independent Checking Unit, on Wednesday blamed “systemic defects” for the body’s failure to rectify the use of flammable polyfoam boards and scaffolding mesh during a HK$336...