SINGAPORE - Debris containing asbestos has washed ashore on the Sisters' Islands Marine Park, the latest of the southern islands to be affected by the potentially toxic mineral.
The mineral has, since April, also been found on nearby Pulau Hantu, St John's Island and Kusu Island - islands popular among day-trippers who visit the southern islands for their nature, scenic views of the Singapore Strait, or to worship at the temple or shrine located on Kusu.
The National Parks Board (NParks), custodian of the marine park, said on its website on Saturday (May 19) that it is temporarily suspending the monthly intertidal guided walk at Sisters' Islands Marine Park. Debris containing asbestos had been found at four isolated areas along the beaches in the lagoons on Big Sister's Island.
Affected beaches have been sealed off, the notice said, adding that removal works are expected to be completed by the end of June.
Asbestos is a fibrous mineral that was once a popular component in construction materials. Due to its links to health problems such as lung cancer, its use in buildings was banned in Singapore in 1989, but many earlier structures still contain the substance.
Structures containing asbestos pose no risk to humans if they are intact. However, when there is damage or disturbance - such as sawing and cutting - fibres may be released into the air and inhaled.
Even though the authorities have said repeatedly that short-term exposure to asbestos is not harmful, the repeated occurrence of the mineral has raised questions on how they came to the southern islands in the first place, and if they could have been dumped illegally by errant contractors.
Investigations are now ongoing to determine the source of the asbestos debris.
But in a joint reply to The Straits Times, the SLA, NParks and the National Environment Agency (NEA) said that the collection and disposal of general and industrial waste from offshore islands is regulated by NEA.
"Owners and occupiers of premises on offshore islands manage the collection of their waste from the islands for disposal at the mainland. This includes waste generated by contractors engaged by the owners or occupiers," said the statement from the agencies.
Investigations and asbestos removal works are now ongoing.
Asbestos was first found on St John's Island in April, leading the Singapore Land Authority (SLA) to seal off more than half the island as a safety precaution.
Subsequently, in early May, SLA said in a media release that asbestos-containing debris had been found on nearby Kusu Island.
It also said then that works were being done to see if the mineral could also be found on Pulau Hantu. As it turned out, it could.
ST understands that notices were put up at the Pulau Hantu jetty last Saturday (May 12) informing visitors that asbestos removal works were ongoing there.
As for the other southern islands - Lazarus Island, Pulau Seringat and Kias Island - no asbestos debris has been found there, SLA said.
Asked about the other offshore islands open to the public, the three agencies said no debris containing asbestos was found on Coney Island, located to the mainland's north-east . As for Pulau Ubin off the eastern coast of Singapore, the authorities told ST that surveys are ongoing at Pulau Ubin and this is expected to be completed by early next month.
"If asbestos is found on the island, NParks will undertake the necessary removal works and precautionary measures to safeguard public safety," said the statement.
Mr Stephen Beng, head of the Nature Society's (Singapore) marine conservation group, said the impact of asbestos on marine life at Sisters' Islands - the Republic's one and only marine park - remains to be seen.
He said: "It depends on the volume of asbestos in the water column and seabed. It does, however, constitute to the growing marine debris threat which kills marine animals like our sea turtles."
He added that the Friends of the Marine Park community - comprising experts, scientists and naturalists - is working on a safety advisory for all involved in marine clean-ups.
Ms Ria Tan, who documents the wildlife found on Singapore's shores, said she was heartened that the authorities were making an effort to identify and remove the asbestos.
"But it is disconcerting to learn that asbestos has been found on so many offshore islands. I hope the source and pathway of this asbestos can be identified so that this issue can be permanently resolved," she said.
She added that the authorities could work with the community for more eyes on the ground. "I am ready to help look out for and report asbestos during my regular shore surveys. But I do not now know what to look out for," Ms Tan said.