The toy trains and railroad pieces are made directly for RC2 at plants it oversees in China, presumably giving it some control over the quality and safety of the toys made there. Staci Rubinstein, a spokeswoman for RC2, declined on Monday to comment on safety control measures at company plants in China.

Image A worker at a factory in Dongguan, China, uses a marker to touch up the paint on toy trains. Several Dongguan factories make Thomas toy trains. Credit... Ryan Pyle for The New York Times

The Toy Industry Association, which represents most American toy companies and importers, also declined to comment.

Julie Vallese, a spokeswoman for the Consumer Product Safety Commission, said the agency recognizes that more must be done to prevent the importation of hazardous toys and other products from China. “It is a big concern. And the agency is taking steps to try to address that as quickly as possible,” Ms. Vallese said. “Their businesses will suffer if they don’t meet safety standards.”

Scott J. Wolfson, a second Consumer Product Safety Commission spokesman, would not say how long ago RC2 discovered the problem or when it first reported it to federal authorities.

In the last two years, the staff of the consumer product commission has been cut by more than 10 percent, leaving fewer regulators to monitor the safety of the growing flood of imports.

Some consumer advocates say that such staff cuts under the Bush administration have made the commission a lax regulator. The commission, for example, acknowledged in a recent budget document that “because of resource limitations,” it was planning next year to curtail its efforts aimed at preventing children from drowning in swimming pools and bathtubs.

The toy industry in the United States is largely self-policed. The Consumer Product Safety Commission has safety standards, but it has only about 100 field investigators and compliance personnel nationwide to conduct inspections at ports, warehouses and stores of $22 billion worth of toys and tens of billions of dollars’ worth of other consumer products sold in the country each year. “They don’t have the staff that they need to try to get ahead of this problem,” said Janell Mayo Duncan, senior counsel at the Consumers Union, which publishes Consumer Reports. “They need more money and resources to do more checks.”