SINGAPORE — Moments after a "loud explosion" at the Stars Engrg workshop, 22-year-old Bangladeshi national Mehedi was pushed to the floor by a gust of hot air.
"I looked up and saw that the whole workshop was dark and filled with smoke," he said in his witness statement to an inquiry committee investigating a blast that killed three migrant workers at the Platinum@Pioneer industrial building at 32E Tuas Avenue 11, on 24 February this year.
"I realised that I was burning and that my clothes had burned off, leaving me with only my pants. I crawled out of the workshop through the front shutters."
Mehedi then ran to an open field at the back of the industrial estate, where his Stars colleagues Rahad and Yousuf were. "We were in a very bad condition and were shouting for help. Workers in the vicinity and from neighbouring units came out and started throwing and spraying water on me and the other injured workers using a hose."
Besides the three fatalities, seven other workers were injured. Five suffered burns, including Mehedi, ranging from 35 to 58 per cent to their body area, with the last worker discharged from hospital in June.
Stars Engrg is a fire protection contractor providing design-built fire protection systems. Stars sometimes uses a fire-rated insulation wrap called Shield+, which it manufactures itself.
Preliminary investigations indicate that the blast was caused by a combustible dust explosion. The dust was in the form of potato starch powder, a material used for production by Stars.
'I often think about the accident'
Mehedi lost consciousness and woke up three days later in the Intensive Care Unit of the Singapore General Hospital's (SGH) Burns Unit. He had suffered burns on his head, face, back, shoulders, arms, hands and leg.
Following his discharge from hospital on 29 April, Mehedi continues to go for outpatient treatment. "The doctors did not tell me how long my treatment will take to complete, but they did say that my scars will not heal completely."
Some of Mehedi's burn areas still hurt. He has bi-weekly physiotherapy as he has lost strength and mobility in his fingers. As his eyes were also burned, Mehedi must wear sunglasses whenever he goes out in the sun.
"I have problems sleeping at night as I often think about the accident. I sometimes awake in the middle of the night and am unable to fall back asleep," said Mehedi, the youngest of the injured workers.
Mehedi spoke in Bengali through an interpreter during Tuesday's (21 September) hearing, which was held at the State Courts.
The mixer machine
Day two of the inquiry was again centred on the upkeep of a mixer machine used to manufacture a fire clay material with ingredients such as potato starch, boric acid and silicon oil. The machine was purchased in August 2019, from Laizhou Keda Chemical Machinery in China, via Alibaba.
The mixture of ingredients was placed in a mixing compartment and heated by an oil jacket filled with thermic oil to make the clay, which would then be wrapped with other materials to assemble the fire wrap.
On the day of the accident, eight workers were tasked to fulfil a production target of 32 rolls of fire wrap. Mehedi's job was to assemble the fire wrap at an assembly table with his colleagues.
On Monday, State Counsel Kristy Tan had pointed out the multiple "red flags" in the months preceding the incident that showed that continued operation of the machine posed "huge risk" to the safety of the workers. They included small fires at the machine's heaters, as well as leaks from the oil jacket.
Numerous repairs were also carried out, such as replacing worn out gaskets, welding a base plate to the underside of the machine, and installing insulation on the oil jacket.
Multiple incidents before the blast
Mehedi told the inquiry committee (IC) that the first fire at the machine broke out some time before 28 August last year, in the form of a small spark. The heater was replaced and the oil drained from the jacket before being poured back in, minus the black sediment that had accumulated.
The following month, there was a small leak from the oil jacket, which had to be welded. Then in October, he was instructed by his colleague Mehedi to drain the oil as it was "dirty", while the oil jacket was again welded due to leaks.
On the afternoon of 12 February, a small fire broke out at the oil jacket. "It looked like a red-orange flame measuring about 250-300mm high and 150-250mm wide," said Mehedi, who together with Yousuf extinguished the fire with a hose reel.
"I then noticed beads of oil dripping down the front bottom right corner of the mixer machine, where the fire had been."
Videos and texts exchanged between Chua Xing Da, the owner of Stars Engrg, and his workers, pertaining to the numerous and incidents, were again shown in court.
At about 8.39am, Marimuthu, who was in charge of operating the machine and died after the blast, shouted, "Mehedi, fire". The flame, which was coming from the heater, was put out by Mehedi using a fire extinguisher.
CCTV footage from the day indicates that a large explosion first occurred at around 11.22am, followed in the next few minutes by flash fires. The force of the blast caused one worker to "fly" about two metres, while the rear wall of the workshop collapsed.
At the time of the incident, Mehedi was wearing a long-sleeved shirt, long pants, slippers, socks and gloves. He also used a respirator. Asked by State Counsel Sivakumar Ramasamy if there were any clothing requirements, Mehedi demurred but added that Chua was insistent on the workers using two pieces of safety equipment.
"If we did not wear the respirator or safety shoes, Boss would get very angry and order us to wear it," he said, adding that he usually did not wear the shoes when assembling the fire wrap.
First tranche of hearings
A total of 15 witnesses will be heard. Investigators from the Singapore Civil Defence Force's Fire Investigation Unit, as well the Ministry of Manpower, will also testify.
The IC is chaired by Senior District Judge Ong Hian Sun. He is assisted by Lucas Ng, general manager of the plant at Petrochemical Corporation of Singapore, and Dr Peter Nagler, chief innovation officer at A*Star. It was appointed by former Manpower Minister Josephine Teo in March.
Its role is to inquire into and ascertain the causes and circumstances of the accident. It will also determine if criminal proceedings should be initiated against any individuals.
The public can attend the first tranche of hearings from 10am to 5pm at Court 8A of the State Courts on the following days: 20 to 24 September, 27 September to 1 October, and 4 to 8 October.
Court capacity is limited due to safe management measures, and dates and timings may change.
The hearing continues on Tuesday afternoon.
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