The Hong Kong government estimated that 150 tonnes of the pellets may have been spilled on its beaches, of which a third have been cleaned up so far.

Local media questioned the government's lack of public notice about the spill, almost two weeks after Typhoon Vincente which was upgraded to Signal 10. It was the first time since 1999 that the city's meteorological body had invoked its highest measure.

In response, the government said its marine and environmental protection departments responded immediately after receiving public complaints on July 24 and 26 respectively.

Both departments are working with the ship owner to clean up the spill, they said in a joint email reply. The Environmental Protection Department said water quality had not been affected.

Gary Stokes, a representative for Sea Shepherd Conservation Society, an international marine life conservation non-profit and another stakeholder in the clean-up operation, said the government had been forthcoming with its assistance.

China Petroleum and Chemical Corp (Sinopec)(600028.SS)(0338.HK), manufacturers of the pellets, told Reuters the pellets were not toxic or hazardous on their own.

But while the pellets are harmless in their original state, they absorb toxins and pollutants over time and could poison the food chain when marine creatures consume them.

Also known as nurdles or mermaid tears, the tiny pellets are widely used to make plastic products.

"It looked like it snowed in east Lamma," said Sea Shepherd's Stokes, referring to the beaches on the eastern coast of Lamma island, just south of the main Hong Kong island and around which remnants of three 40-foot containers holding thousands of 25-kg bags of the white-coloured pellets were found scattered. (Reporting by Clement Tan and Tan Ee Lyn; Additional reporting by Chen Aizhu in BEIJING; Editing by Stephen Powell)

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