SINGAPORE - The boss of Stars Engrg broke down in tears as he recounted how he felt after an explosion at the company's Tuas workshop killed three of his workers, including one he said was more than just an employee to him.

Mr Chua Xing Da, 37, the sole director of the fire protection company, said he was greatly saddened and affected by the incident on Feb 24.

The blast at around 11.20am that day at the workshop at 32E Tuas Avenue 11 had injured eight of his workers, including three who later died.

Mr Chua, testifying for the third day on Monday (Sept 27) before an inquiry committee, said that Mr Subbaiyan Marimuthu, 38, was a worker he thought highly of.

"(The relationship) between Marimuthu and I was more than just employee and employer," he said between tears.

"He worked for me for so many years... I'm very affected."

Mr Marimuthu worked with Mr Chua for more than six years, and was a trusted supervisor.

He was one of the three who died from severe burns that covered 90 per cent of their bodies.

Mr Chua said he was also deeply affected by the loss of the other two workers, Mr Anisuzzaman Md, 29, and Mr Shohel Md, 23, and the state of the other workers injured in the blast.

He told the committee that the company has been providing and will continue to provide financial aid to the families of the workers who died, sending them what would have been their full salaries every month.

Asked what the company has been doing to help the injured workers, Mr Chua said it has been helping them in any way it can, paying for treatments and operations.

"Whatever they need, we say okay. We will never say or think it's not necessary," he said.

"I have never shortchanged, from the accident till now, any one of them."

Monday was the final day that Mr Chua was testifying before the committee.

He was questioned about the operations at the Tuas workshop and the work safety measures, as well as the mixer machine which was linked to the explosion.

Stars Engrg made an insulation material called fire wrap using the machine that heated up oil, which then heated water and mixed it with ingredients, including potato starch.

The machine, bought through online platform Alibaba, was installed at the Tuas workshop in June last year.

There had been many red flags involving the machine before the explosion, including leaks, smoke and fires.

Less than three hours before the explosion, the machine had again caught fire, but this was put out by workers.

Mr Chua said he had tried to inculcate a work culture of safety among the workers, threatening them with fines for not wearing the proper attire but never actually handing out any.

Instead, he said he would scold them and issue them stern warnings.

He added that he did not expect the machine to explode.

He said: "If I had known this thing would explode, I would not have bought this. Why would I need to buy a time bomb?"

The committee was told that before the explosion, the machine had been glowing red hot, with Mr Chua estimating the temperature to have been around 700 deg C.

Mr Chua has also been unable to answer several questions relating to the machine and safety measures, saying he had assessed the safety risk to be low and that he genuinely believed it was safe.

He testified last Thursday about how he had convinced Mr Marimuthu that the machine was not dangerous, even after the worker said he was scared.

The first tranche of hearings will last till Oct 8, while the second tranche is expected to be from Nov 15 to 19.

Mr Lwin Moe Tun, the company's project engineer, was initially set to testify on Tuesday, but the committee was told he has been feeling unwell.

He had allegedly deleted photos and messages from his phone and Mr Marimuthu's after the explosion, but these were recovered by the police.

The State Counsel team led by Ms Kristy Tan said four workers who were injured in the blast will thus be testifying first this week, presenting their statements to the committee chaired by Senior District Judge Ong Hian Sun.

Investigators from the Singapore Civil Defence Force and Ministry of Manpower are also expected to testify in the coming days.