A NURSE yesterday suffered burns on her left buttock after sitting on an unknown substance in a public area - the second such incident in two weeks.

Ms Wan Zahfirah Arshad, 24, was on a north-bound SMRT train heading towards Jurong East at 11am when she sat on what could have been acid.

After alighting, she experienced an unbearable tingling sensation and noticed a yellow substance on her clothes.

A spokesman for the Singapore General Hospital confirmed that she is currently warded at the hospital for 3 per cent burns.

SMRT, expressing shock at the incident, lodged a police report after speaking with the passenger and ensuring that she is well taken care of.

The police confirmed they were informed "of an unknown substance found on a train and a woman who had sought medical consultation in relation to the case".

Investigations are ongoing.

On April 17, School of Science and Technology student Aung Phone Naing, 14, suffered second-degree burns on his right thigh after sitting on a "transparent liquid" at a bus stop along Bukit Batok East Avenue 3.

The Singapore permanent resident, who is from Myanmar, went to the National University Hospital but tests failed to identify what he sat on.

WALTER SIM