It is estimated there are at least 100 to 200 production companies in China with an annual capacity of 14 billion dinnerware items made of plastic foam. [File photo]

It is estimated there are at least 100 to 200 production companies in China with an annual capacity of 14 billion dinnerware items made of plastic foam, according to China National Radio.

Some Shanghai residents said they were concerned about toxic substances if the products were heated.

"I learnt that plastic foam will discharge carcinogen after being heated, and I think the ban should remain for the sake of health and the environment," said Yu Jia.

However, experts said while extremely high temperatures could lead to toxic substances being released, it was not a serious problem.

At temperatures below 70 degrees Celsius, there would be no harmful substances, said Yang Huidi, an expert with the China Plastics Processing Industry Association.

Li Peisheng, director of China's Plastic Dinnerware Office, said the cost of disposable dinnerware made of plastic foam was half that of the cheapest disposable dinnerware previously allowed, and it performed better in resisting water and oil and in keeping food warm.

It was lighter than other dinnerware, used fewer materials, produced less garbage and could be recycled, he said.

Cao Jian, an official with China's plastic processing association, said better management and recycling were key to preventing pollution.