US health authorities have raised the safety threshold for melamine for infant formula amid widespread concern over the use of the industrial chemical in Chinese dairy products.
Melamine is used to line cans, make flame retardant and cleaning products, and does not occur naturally.
"Levels of melamine alone or cyanuric acid alone, at or below 1 part per million (ppm) in infant formula do not raise public health concerns," the US Food and Drug Administration (FDA) said in a statement Friday.
"FDA's ongoing investigation continues to show that the domestic supply of infant formula is safe and that consumers can continue using US-manufactured infant formulas," the agency added in an update on melamine contamination in China.
At least four children have died of kidney failure and 53,000 have fallen ill in China this year after consuming milk or dairy products laced with melamine.
The dairy scandal has expanded worldwide with several governments recalling or banning Chinese products with milk content.
FDA tests had previously found traces of melamine or cyanuric acid in infant formulas produced in the United States.
In October, the FDA indicated it was unable to set a safety level for melamine found in infant formula but said that the chemical was safe at 2,500 parts per billion in other foods.