TBILISI (Reuters) - Seventy-three people were treated in hospital after a chlorine leak at a water distribution company in Georgia late on Tuesday, a Tbilisi city official said.

"Around 30 patients are still in hospitals, but the majority of them will be discharged by the end of the day," Temur Grigalashvili, told Reuters on Wednesday.

The leak was caused by the malfunction of a tap on a tank containing chlorine.

Nearly half of those taken to hospital were on a bus that passed through the area in Tbilisi where the leak occurred, Grigalashvili said.

An 18-year-old male patient suffering from asthma was in a serious condition, he said.

The leak no longer presented any threat to people or the environment, Georgia's Environment Minister Goga Khachidze told television channel Imedi TV.

(Reporting by Margarita Antidze; Editing by Janet Lawrence)