AIRPORT chiefs rejected a simple solution to the problem of Chek Lap Kok's toilets more than a year before beginning the current multimillion-dollar overhaul, according to a local engineering firm. The firm told the Post it had been invited by officials hired by the Airport Authority to help tackle the odour problem. The officials were impressed by an air-cleaning system the firm installed for a trial period in one toilet block. But seven months later they said they were 'strapped for cash' and could not afford to have the air-cleaning system throughout the airport. They opted instead to install extra air-conditioners, despite the firm's advice that this would only cool the air, not freshen it. The firm, which has fitted the units in a hotel, restaurants and government departments in the SAR, said the purification system worked by electrically charging oxygen in the air and was used at London's Heathrow airport and in hospitals and nursing homes worldwide. It would have cost the authority $1 million to have air-purifiers installed in all 50 public toilet blocks at Chek Lap Kok, the firm said. The Sunday Morning Post reported last month that the authority was spending $7.6 million re-fitting toilets with bigger urinals, new floor tiles, improved lighting and extra air-conditioning to reduce smells, which are still drawing passenger complaints more than two years after the airport opened. 'The problem was traced to a low air-flow rate for air-conditioning in the initial design, and inadequate fresh air, causing stagnant ammonia smells,' the firm's managing director explained. He said one option would have been to reinstall the air-conditioning, but that was prohibitively expensive. The other was to install purification units at $20,000 a block. 'We told them air-conditioning won't solve the problem - you're only masking the smell by cooling it,' he said. The authority's spokesman, Chris Donnolley, said the budget for the current work included lighting, tiling and urinals, not just air-conditioning. He could not say why the firm was turned away.