The Highways Department today said it is investigating the damage of a ventilation fan’s blades of the air purification system at the Central-Wan Chai Bypass & Island Eastern Corridor Link’s (CWB) Middle Ventilation Building.

The CWB’s engineering consultant reported the damage on June 28.

For the sake of safety, the operation of the air purification system at the Middle Ventilation Building has been partially suspended for investigation.

According to air quality monitoring data, the incident does not affect the air quality inside the CWB tunnel.

The engineering consultant carried out a preliminary inspection of the remaining 32 ventilation fans at the three ventilation buildings on June 30 and found no abnormality.

The department explained that it instructed the engineering consultant and contractor to investigate the incident’s cause as soon as possible and carry out a comprehensive inspection of all fans at the three ventilation buildings to ensure they are functioning properly.

The department emphasised that it has grave concerns on the recurrence of abnormal ventilation fan damage at the CWB and will appoint an independent expert to carry out a comprehensive review of the entire ventilation system's design, construction and supervision.

It will also follow up stringently to investigate the cause of the incident and related liability issues.

Once the cause and liability issues are ascertained, the Government will seriously follow up with relevant parties regarding losses caused by the incident, the department added.