All four workers who suffered burns during a fire at a chemical manufacturing plant on Jurong Island are now in stable condition, said Minister of State for Manpower and National Development Zaqy Mohamad.

The fire had broken out on Tuesday while the workers were working on or around a drain valve along a process pipeline, Mr Zaqy said in a Facebook post yesterday after visiting the Singaporean workers.

The Ministry of Manpower (MOM) has halted all works at the affected unit of Mitsui Elastomers Singapore while the cause of the fire is being investigated, he added.

MOM plans to look into the measures taken by the company to address or minimise risks to ensure the safety and health of workers.

The company, a subsidiary of Japan-based Mitsui Chemicals, manufactures high-performance polymers that are used for automotive and packaging materials.

The workers were taken to Singapore General Hospital on Tuesday.

A hospital spokesman said one of the injured workers is still warded in the intensive care unit, but all four are stable.

Said Mr Zaqy: "I would like to remind all employers to take all reasonably practicable measures to address hazards at the workplace. MOM will not hesitate to take action against parties found responsible for workplace incidents.

"Our workers must always be assured of their safety so that they can return home safely to their loved ones," he added.