The boss of Mattel has apologised for safety lapses which resulted in the recall of 21 million Chinese-made toys in recent months.
Leading Senators said safety regulations were not good enough
Robert Eckert told a US Senate hearing that Mattel was "by no means perfect", and acknowledged its Chinese producers had not been monitored closely enough.
But he denied the firm was too slow to reveal safety concerns, saying notice of the recalls had been given speedily.
"Made in China has now become a warning label," Senator Sam Brownback said.
Recent recalls have dented consumer confidence in toys and other goods exported from China and put pressure on US retailers to improve their testing procedures.
Appearing before the Senate Appropriations Committee, Mr Eckert said Mattel was "committed" to upholding safety standards and immediately announcing problems when they were identified.
"We are by no means perfect," he said.
"But we have tackled difficult issues before and demonstrated an ability to make change for the better, not only within our own company but for the broader industry."
Since the initial product recall in early August, Mattel has carried out inspections of all toy shipments from Asia as well as an audit of all of its suppliers.
China has also since agreed to ban the use of lead in toys exported to the US.
A succession of committee members expressed their concerns with current product safeguards, focusing on the oversight role of the US Consumer Product Safety Commission.
"Our toy safety system is not as strong as it should be," said Democratic Senator Richard Durbin.
Toys R US, which recalled thousands of Chinese-made crayons this month, said it would notify customers directly of recalls by e-mail to ensure people got hold of critical information.
"We know consumers are asking how they can be sure the toys they buy are safe," Jerry Storch, the firm's chairman, told the Senate panel.
"We are troubled by the possibility that we could be continuing to sell toys that someone knows may have a problem, while we remain unaware until we receive word that a recall is coming."