While the incident was ongoing, the Land Transport Authority made an announcement on the radio advising motorists in the tunnel to get out of their vehicles and leave the tunnel via their nearest emergency exits, added Mr Tay.
He said that he was stuck in traffic in the tunnel for about 35 minutes.
Another passenger in a vehicle at the scene told CNA that when she got on the MCE at about 6.45pm, traffic was stopped and she was similarly stuck for about 35 minutes.
Additional reporting by Johannes Tjendro.
