When Ms Tan Li-Lin and her husband returned from work last Tuesday, they thought their five-room Punggol flat had been burgled.
On the floor were shards from the dining table's glass top, which had shattered and sent fragments to as far as the bedroom hallway.
After checking that nothing else was amiss, the couple realised that the glass had shattered on its own.
"Thankfully no one was at home when it happened," Ms Tan, a 33-year-old who works in communications, told The Straits Times. "It was just painful to clean up - they (the shards) had got into the couch, carpet, everywhere."
The dining table, bought for about $2,000 from a furniture store at Marina Square about three years ago, had no visible cracks or chips on the tempered glass top, she said.
In a separate incident on Sunday, a Turbo Italia tempered glass top gas stove shattered in a Pasir Ris flat.
Both gas cookers and dining table furniture are subject to safety regulations under consumer product safety authority Spring Singapore.
Tempered glass is commonly used for glass tops of gas and electric hobs as well as table tops as it lasts longer and is more impact- and heat-resistant, Spring said.
Glass experts said spontaneous shattering occurs only in tempered glass. But there is no cause for panic, they said, as such cases are not common. Also, tempered glass implodes, shattering into small pieces with rounder edges than that of normal glass, reducing the risk of injury.
A check with the Consumers Association of Singapore found that it has received nine complaints since 2014 about furniture with glass parts shattering, and five complaints about shattering glass stoves and cooker hobs.
Experts said tempered glass is about four times stronger than untreated glass as it is strengthened through heat. But the tempering process creates surface stress which, combined with nickel sulphide inclusions created during the glass manufacturing process, can cause the glass to spontaneously shatter months or years later.
Lower-quality glass contains more sulphide inclusions, which increases the likelihood of spontaneous shattering, experts said.
A safer option is laminated glass, which is two layers of glass joined by an adhesive. The glass surface holds together even when broken, as the broken pieces stick to the adhesive. But laminated glass can be nearly twice as expensive.
Business development manager Gary Lee of Singapore Safety Glass said consumers can also ask if tempered glass has been heat-soaked, a process that tests for spontaneous breakage. Safety film can be applied to tempered glass, or a tablecloth placed over table tops to avoid injury if shattering occurs, he said.
Meanwhile, Turbo Italia's distributor Happiness Pte Ltd told The Straits Times it had conducted a joint investigation with gas supplier City Gas and found that the product was not faulty. It added that it has maintained a 0.1 per cent glass shattering incident rate.
Safety tips for using tempered glass gas cookers include avoiding the use of oversized or heavy cooking utensils, as well as the use of aluminium foil or other materials to cover the tempered glass top or overspill trays, said Spring.
Consumers with safety concerns related to household electrical, electronic and gas products or consumer goods can contact Spring.
• Additional reporting by Jose Hong