SINGAPORE - Passengers on board an east-bound train were forced to disembark at City Hall MRT station on Thursday night after one of the cabins was filled with smoke.

The smoke was due to a refrigerant gas leak from the air-conditioning system of the first-generation train, which has been running since 1987, said SMRT Trains president Lam Sheau Kai in response to queries from The Straits Times.

The incident took place at about 9.50pm and the affected train was withdrawn from service.

Apologising for the disruption, Mr Lam said passengers were told to disembark as a safety precaution and advised to board the next train.

“Our staff did not receive any reports of commuters who required medical attention,” he said, adding that train services continued as normal afterwards.

Footage of the incident was posted on social media, with a video showing passengers on the train covering their mouths and noses as smoke envelops the cabin.

The 33-second clip also shows an SMRT Trains staff member checking each cabin as passengers stream out of the train into the station.