It was 11am and staff at Lavish Dine Catering in Bukit Batok were busy cooking to fulfil their orders for the day when the sound of a loud explosion brought work to a halt.
Walking out of their unit, Lavish Dine's sales manager Ryan Koh said he saw chaos. "Debris was lying here and there, people were injured. One auntie was quite badly burned, others had cuts."
An industrial incident at their neighbour's 11th-floor Enterprise Centre unit had left five people hurt.
The Singapore Civil Defence Force said it responded to the incident at 20, Bukit Batok Crescent around 11am yesterday. "The industrial incident resulted in the partial collapse of a wall and significant damage within the premises," it said.
There was no fire and no one was trapped. One of the workers suffered burn injuries and was taken to Singapore General Hospital, while the others were taken to Ng Teng Fong Hospital.
The explosion originated from a unit occupied by ZTP Ginseng Birdnest, which specialises in health products. One of the company's listed directors, Mr Phang Kwee San, told The Straits Times he was saddened by the incident.
Of the five workers injured, four are Singaporeans and one is from China. Mr Phang said two underwent an operation yesterday and all were in stable condition. "Right now, I am not sure what happened. We will have to wait for investigations to conclude before we will know."
The Building and Construction Authority (BCA) said it had inspected Enterprise Centre and "assessed that the structural integrity of the building, including that of other units, is not affected by the incident". The only tell-tale signs of the incident were a fire engine and shattered windows and broken frames dangling from the 11th floor. The affected area was also cordoned off.
A BCA spokesman said: "Parts of the window panels and false ceilings of two units on the 11th floor were damaged, and a non-structural brick wall within them had partially collapsed."
Other tenants in the building said they heard a loud noise. Those at Deluscious Patisserie on the 13th floor even felt vibrations. Said an employee at the Tung Lok Restaurants unit on the 11th floor, who wanted to be known only as Mr Li: "I heard an explosion and it was quite loud, even though we are four units away."
Madam Joanne Sim, who runs a claypot rice stall at the ground- floor canteen, said: "The police told us to turn off the gas and it affected our business." Gas in the building was still turned off as at 5pm yesterday, said Mr Koh, whose colleagues switched to using electrical stoves instead. "Thankfully, we have the electrical stoves and are still able to meet our catering demands," he said.
ZTP Ginseng Birdnest told Chinese evening daily Lianhe Wanbao that its Bukit Batok factory was a small one and its main factory in Tuas, along with its retail shops, will operate as usual.
• Additional reporting by Clara Chong and Lee Min Kok
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Wall collapses at Bt Batok factory building. str.sg/4VXq