A killer blaze could be one spark away in 21,400 buildings which have failed to comply with safety regulations. Only 13,600 of an estimated 35,000 buildings required to have their electrical installations checked and certified at least once every five years have done so. The Electrical and Maintenance Services Department is investigating whether the On Hing Building in Kwun Tong is among those to have flouted the law. There was no record of spot checks on the building or residents' complaints. According to the Electricity (Wiring) Regulations, issued in 1992, all affected buildings should have had their certification by May 31 last year. The fact that so few complied was 'not satisfactory', said Senior Electrical and Mechanical Engineer Lo Kin-hung, who promised to step up spot checks and prosecutions. Those concerned about electrical installations can call 2882 8011.