The toys contained high levels of phthalates, which are chemical plasticizers used to make materials softer and more pliable, authorities said. Congress has banned the chemical in children's toys.
The U.S. Commercial Targeting and Analysis Center began targeting the shipments in April because they threatened children's safety, authorities said.
"Using advanced technology to track certain shipments before they reach our shores is helping CPSC better protect America's consumers," Consumer Product Safety Commission Chairman Inez Tenenbaum said in a statement.
U.S. authorities didn't identify the manufacturer of the toys Tuesday.
A total of 10 shipments valued at almost $500,000 were seized at the ports of Chicago; Dallas; Los Angeles; Norfolk, Virginia; Memphis, Tennessee; Newark, New Jersey; Portland, Oregon; and Savannah, Georgia, authorities said.
Tenenbaum said her agency and the U.S. Customs and Border Protection have been targeting dangerous imports at several major ports through the use of a risk management system. Those efforts resulted in the seizure of more than 1.1 million unsafe products last fiscal year, authorities said. At the same time, the system also allows "for faster processing of compliant products," she said.
Image: Toy doll, via Shutterstock