What was meant to be a fun trip to the beach ended up being a messy affair after a group of kids found their hands, feet, clothes and toys stained with a black, sticky, unidentified substance. 

On June 21, their parents took them camping at East Coast Park at Area G near the National Sailing Centre for the school holidays. 

However, after playing in the water at the beach at around 7.30pm, one of the boys came back covered in a mysterious substance, one of the mothers of the children surnamed Chen shared with 8world. 

The boy, who is Chen's eldest son, said he had stepped on a "large soft object". Subsequently, the rest of the children returned covered in the same substance too. 

When the parents tried to remove the stains by rubbing them with sand or soap, the substance would not budge.

It was only removed four hours later when they used paint remover. 

Chen also noted that while they were trying to clean off the substance in the toilet, there were other people in the same predicament as them, including a young couple as well as middle-aged and elderly folks who had gone to the park for a night walk. 

As a frequent beach goer, Chen shared that she has not encountered anything like this before.

While the parents said they have not identified what the mystery substance could be, the mother suspects that it could be waste oil or some leakage from a cargo ship moored near the coast. 

She also added that when the families arrived at the beach around 3pm, the water "was clean". 

"I don't know if the waste oil from the sea was brought in because the tide turned in the evening." 

The next morning, when Chen returned to the beach, she noticed that the mystery substance had solidified into lumps. 

AsiaOne has contacted the National Environment Agency (NEA), the National Parks Board and the Maritime and Port Authority for comment. 

On their website, NEA also said that it "regularly monitors the water quality of coastal areas" and the water samples are analysed for anomalies due to oil spills or algae blooms that may affect the fish farms and marine environment in Singapore.

According to the 1999 Oil Spill Intelligence Report, the Straits of Singapore is considered to be one of the world's hot spots for oil spills and since 1960, there have been over 39 spills totalling more than 34 tonnes, said a report in Singapore Infopedia. 

Back in 2014, oil-slicked beaches at Kusu Island and St John Island were temporarily closed after a ship collision. 

In 2016, the sand at Changi Beach was also stained by oil after two container vessels collided and spilt almost 300 tonnes of oil into Singaporean and Malaysian waters.

Workers had to be deployed to pack the affected sand into trash bags, reported The Straits Times then.

melissateo@asiaone.com

For more original AsiaOne articles, visit here.