Five firemen, aged 26 to 44, have been injured fighting a blaze at the old airport passenger terminal at Kai Tak.
They were sent to Queen Elizabeth Hospital, and three were discharged after treatment, while two remain for observation.
The fire erupted at 9.30am on the first floor and spread to the upper floors. Firemen used eight jets and 12 breathing apparatus teams to fight the blaze. Fifty-one workers were evacuated.
