SINGAPORE – Trains travelling along the North-South Line skipped Novena MRT station on Friday evening after an air-conditioning unit filled the underground station with smoke.

The incident led SMRT to close the station and trains to skip the stop for about two hours during the evening travel peak.

A video posted on Facebook at about 5.45pm showed smoke trailing upwards from the station platform to the gantries of the MRT station.

SMRT said in a post on X, formerly known as Twitter, that the station was closed as at 5.49pm because of an “incident”, without providing details. It said in a subsequent post at 7.29pm that the station had reopened for service.

Apologising for the inconvenience caused, SMRT said free bus services were available for passengers travelling between Newton and Toa Payoh stations. These were still available even after the station reopened.

Several Singapore Civil Defence Force (SCDF) vehicles, including a fire engine and Light Fire Attack Vehicles, were spotted outside the station during the incident.

SCDF said in a Facebook post that SMRT had alerted it to “white smoke” and a burning smell at the Novena station’s concourse area at about 5.30pm.

“Upon SCDF’s arrival, the white smoke... had dissipated. Following preliminary investigations by SCDF and SMRT, the source of the white smoke was determined to be from the motor of an air handling unit inside a room at the concourse level,” it said. No one was injured.

An air handling unit is a large commercial air-conditioner.

SMRT has since isolated the unit’s system for further investigations. It referred ST to its social media channels when approached with queries.

Civil servant Joanne Loh arrived at the station only to hear an announcement that “the station is still investigating the cause of the alarm”. Passengers were instead asked to take the feeder bus service. SMRT staff told commuters that the trains were fine, but the station had an “issue”, she said.

The 33-year-old added that the bus stop was very crowded, and there was heavy traffic in the area.

“I’m not thrilled to take a longer route to my destination (Rochor MRT station), but I guess it can’t be helped,” she said.

• Additional reporting by Elaine Lee