Swimmers not told for hours about large leak of raw sewage into the sea

Bathers may have been unknowingly swimming for hours in water polluted with raw sewage after officials and a contractor delayed notifying beach managers of problems at Pillar Point sewage treatment works on Monday.

Under the emergency response plan for the plant, the Leisure and Cultural Services Department, which oversees the city's beaches, should be informed by the contractor within an hour of any sewage discharge. But the first sewage was discharged at 3.30pm and the department was not informed until 6.30pm, a Drainage Services Department official said.

Another government department that should be informed within an hour said yesterday it had still not been notified.

The news emerged yesterday as the 14 beaches in Tuen Mun and Tsuen Wan districts that were closed at about 10pm on Monday night finally reopened. Many swimmers had ignored the beach closure notices and warnings from lifeguards as they swam as usual on Tuesday.

At least 95,000 cubic metres of raw sewage was discharged into the sea during the six-hour leak from the Tuen Mun plant, which was commissioned in May.

Anthony Tsang Kwok-leung, chief engineer of the Drainage Services Department's harbour area treatment scheme, denied there was any cover-up but acknowledged there was room to "further improve notifications".

Drainage officials have ordered the plant contractor - which was responsible for construction and design as well as the plant's operation - to produce a report on what they called an "extremely rare" incident involving failure of all three silt-screening units and a back-up.