An intense blaze involving an oil storage tank was quelled around midnight on Tuesday after a six-hour firefighting operation involving several agencies.
There were no reported casualties from the fire that broke out just before 6pm on Tuesday at Pulau Busing, an island south-west of Singapore which is home to oil and chemical storage facilities.
Photos and videos circulating online showed dense plumes of smoke rising from the island, which is leased to petroleum storage company Tankstore.
However, residents in the Telok Blangah and West Coast areas told The Straits Times they did not notice the blaze until they saw the news on Tuesday evening.
The Singapore Civil Defence Force (SCDF) said the "massive" operation involved 128 of its personnel and 31 firefighting and support vehicles. They were supported by members of the Company Emergency Response Team (Cert) and agencies including the Police Coast Guard, Maritime and Port Authority of Singapore, Republic of Singapore Navy and National Environment Agency (NEA).
The operation required the SCDF to ship necessary equipment and vehicles from Pasir Panjang Ferry Terminal to the island. Two large foam jets were deployed to battle the blaze, while five unmanned water monitors were used to cool adjacent oil tanks and prevent the fire from spreading.
In a Facebook post, the SCDF said heat from the burning tank posed a "major challenge" to firefighters.
The SCDF also said the prolonged operation saw firefighters take turns to recuperate before heading back "into the thick of action".
The SCDF said the cause of the fire is being investigated. Tankstore did not respond to queries by press time. According to its website, the Pulau Busing facility has 112 tanks with a total capacity of 2 million cubic metres of storage for all types of petroleum and petrochemical products. The tanks are also equipped with a "technologically advanced fire protection system".
In 2011, a fire broke out at oil giant Shell's manufacturing site on Pulau Bukom and raged for 32 hours, injuring six workers.
The NEA said on Tuesday night that there were no spikes in levels of harmful PM2.5 particles and other air pollutants, and that it was monitoring the air quality closely.
The one-hour PM2.5 reading remained in the normal range as at 3pm yesterday, according to the NEA's haze website.
Minister for Home Affairs and Law K. Shanmugam visited the site in the early hours yesterday and commended the agency for an "incredible job" in a Facebook post.
He said that the SCDF had to be precise in planning the operation to target and deploy fire appliances to the necessary areas, adding: "A complex operation. But SCDF planned and executed well."
Additional reporting by Tiffany Fumiko Tay