SINGAPORE - Two workers died days after they were found floating in a tank filled with waste water at a leather dyeing factory last year. In the coroner's inquiry yesterday into the deaths of the Chinese nationals, questions were raised about workplace safety.
On Dec 26 last year, Mr Yang Zhonghua and Mr Zhai Hailei were found unresponsive in a sump at Nam Heng Leather Dyeing at Tai Seng Industrial Estate, near Airport Road.
Ministry of Manpower (MOM) investigating officer Mark Eugene Han told the coroner's court that the victims had not used personal safety equipment such as safety harnesses, face masks and safety boots.
He said: "(Wearing) a safety harness would have been ideal... (Mr Yang) was not wearing anti-slip boots."
Mr Yang, 37, was tasked that morning with removing a waste residue basket from under a tank that drains into the 3m-deep sump.
It was not clear how he ended up in the sump, which was filled with 2.5m of waste water at that time.
Mr Han said that there was no ladder in the sump and the factory did not have safety drills to deal with such an accident.
When asked by State Counsel Paul Wong how the men could have ended up in the sump, Mr Han said it was his belief that the high levels of hydrogen sulphide - a by-product of the leather tanning process - had overwhelmed them.
Exposure to high concentrations of hydrogen sulphide can result in eye irritation, dizziness and disorientation, he said.
In addition, there were no gas monitoring and air pump systems to suck up poisonous gases in the factory.
When questioned by Mr Wong, the factory manager, Mr Ang Keat Hong, 39, clarified that Wellington safety boots had been issued to the two men.
He added that gas masks were used only for tasks involving acids and other chemicals.
Mr Ang said that the factory was relocated to the present site in 1998 and that, at the time, there was no requirement for a gas monitoring system.
Asked by Ms Wong Shi Yun from Rajah and Tann, who is representing the company, whether such a system had been enforced by safety inspectors, Mr Ang said: "We were not told by inspectors to install any gas suction pipes."
As for the lack of a safety drill, he said it was because the sump was usually covered and the possibility of someone falling into it was "very small".
Mr Ang also disagreed with Mr Han's belief that hydrogen sulphide had caused the workers to fall into the sump as it would take prolonged exposure of six or seven hours to "knock out" a person.
Nevertheless, State Coroner Marvin Bay said it was a "fairly important point" to establish the concentration levels of hydrogen sulphide at the time of the incident.