The oil spill that caused Paterson Road to be closed for 13 hours, and which resulted in widespread congestion for much of Thursday, could have ended a lot worse.
Experts The Straits Times spoke to said it was potentially a very dangerous situation, and it was fortunate that no lives were lost in the incident.
Adjunct Associate Professor Gopinath Menon, from Nanyang Technological University's School of Civil and Environmental Engineering, said: "The spilt oil could have been corrosive or flammable. People could have been hurt or burnt."
It was an inconvenience for motorists but no lives were lost, he added.
The spilt oil is believed to have come from a truck, and the driver is now assisting with investigations.
The incident was first reported to the police at around 1.30am on Thursday, after which the Singapore Civil Defence Force and National Environment Agency took turns over six hours to clean the road with water jets, detergent and sawdust.
All five lanes on Paterson Road, heading towards River Valley, were closed to traffic from about 3.50am, which resulted in a massive tailback on roads feeding into the area.
Experts said identifying the type of oil and washing it away are the first things to do when dealing with such situations.
"The type of oil has to be determined so that the right solvent can be used," said Mr Abdul Gaffor, head of training at safety training firm KAV International.
Some oils could result in irreversible damage.
As tarmac road surfaces are made from oil-based bitumen, spills of lighter oil products will quickly degrade them, said Mr Darren Waterman, regional director for the Asia-Pacific at Oil Spill Response.
"Spilt petrol can penetrate the tarmac surface, making it more malleable, and the aggregate in the tarmac could become loose. The tarmac would then be less capable of supporting loads or movements of vehicles... In many instances, the road surfaces have to be removed and replaced," he added.
This was what the Land Transport Authority did yesterday at about 10am, after clean-up efforts were exhausted.
Replacing the road surface was unavoidable if the oil had seeped beneath the road surface, said experts.
"When it rains, the oil will float up again and make the road slippery and dangerous," said Mr Abdul. "It was an extreme measure but it can't be helped," he added.