China knew about problems with magnets on toys as long ago as March, an industry official said on Wednesday, following a second massive recall of Chinese-made Mattel toys due to hazards from small, powerful magnets.

China has been struggling to convince the world its products are safe after a series of scandals over everything from tainted pet food and drugs to tyres, toys and toothpaste.

Mattel Inc, the largest US toy company, recalled millions more Chinese-made toys on Tuesday due to safety risks from the magnets and lead paint and warned it may recall additional products as it steps up testing.

“We knew about the situation, because since March some toys had been recalled due to magnetic parts problems,’’ said an official with the China Toy Association, who declined to be identified.

She did not explain why it had taken so long for something to be done.

The new recall involves 18.2 million magnetic toys globally, including 9.5 million in the United States, with magnets or magnetic parts that can be dislodged.

About 253,000 Pixar Sarge die-cast toy cars with lead paint were also recalled. Lead has been linked to health problems in children, including brain damage.

The China Toy Association would meet the Commerce Ministry and quality watchdog later in the day to discuss the recall, the official said.

The recall will likely only add to US consumer worries about the made-in-China label. According to a poll last week, nearly two-thirds said they would support a boycott of Chinese goods.

“There is a very kind of widespread sense in America now that there may be something defective with a number of Chinese products,’’ said James Fallows, a lecturer in US foreign policy at Shanghai’s Fudan University.

“I think it won’t be so big an item in actual government-to-government negotiations, but in terms of normal commerce, it will be a factor.’’