EIJING - China rejected a warning by the US Food and Drug Administration urging consumers to avoid using Chinese toothpaste because it may contain a poisonous chemical used in antifreeze.

Calling the warning "unscientific, irresponsible and contradictory," China's food regulator said in a statement late Saturday that low levels of the chemical have been deemed safe for consumption.

The FDA increased its scrutiny of toothpaste made in China after reports that some brands contained diethylene glycol, a thickening agent used as asubstitute for glycerin, a sweetener commonly used in drugs.

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The US agency was not aware of any poisoning, but found toothpaste with the chemical in a shipment at the US border and at two bargain retail stores in the US

In its statement, China's General Administration of Quality Supervision, Inspection and Quarantine said a list of ingredients in toothpaste exported to the US is offered to the FDA, showing the amount of diethylene glycol. Also, the toothpaste's labeling had already been registered with the FDA, allowing it to be sold in the U.S, the statement said.

Experts from the Health Ministry have deemed diethylene glycol a "low-level" poison that does not accumulate in the body, it said, adding the regulator found no evidence that the substance caused cancer or deformities.

European Union standards allow for a certain amount of the chemical, it said, and a Chinese study in 2000 found toothpaste containing less than 15.6 percent of diethylene glycol was not harmful.

"Therefore the warning issued by the FDA is unscientific, irresponsible and contradictory," the agency said, noting it was "highly concerned" by the move.

The agency "requests the US clarify the facts in a scientific manner as soon as possible and properly handle the issue."

The FDA alert Friday said it found diethylene glycol, or DEG, in three products manufactured by Goldcredit International Trading in China: Cooldent Fluoride, Cooldent Spearmint and Cooldent ICE. Analysis of the products revealed they contained between 3 percent and 4 percent DEG.

The agency also found the chemical in one product manufactured by Suzhou City Jinmao Daily Chemical Co., Shir Fresh Mint Fluoride Paste, and discovered it contained about 1 percent DEG.