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

Calling the FDA warning "unscientific, irresponsible and contradictory," China's General Administration of Quality Supervision, Inspection and Quarantine said in a statement posted on its Web site late Saturday that low levels of the chemical have been deemed safe for consumption.

The FDA increased its scrutiny of toothpaste made in China because of reports that the products may contain diethylene glycol, a thickening agent used as a low-cost — but frequently deadly — substitute for glycerin, a sweetener commonly used in drugs.

Brands of toothpaste from China that contain DEG are:

Cooldent Fluoride, Cooldent Spearmint, Cooldent ICE, Dr. Cool, Everfresh Toothpaste, Superdent Toothpaste, Clean Rite Toothpaste, Oralmax Extreme, Oral Bright Fresh Spearmint Flavor, Bright Max Peppermint Flavor and ShiR Fresh Mint Fluoride Paste.

The agency was not aware of any poisoning but found toothpaste with the chemical in a shipment at the U.S. border and at two bargain retail stores, a Dollar Plus in Miami and a Todo A Peso in Puerto Rico.

China's main food safety regulator said in its statement that the ingredients of toothpaste exported to the U.S. is offered to the FDA, showing the amount of diethylene glycol. Also, the toothpaste's labeling has already been registered with the FDA, allowing it to be sold in the U.S, the statement said.

The General Administration of Quality Supervision, Inspection and Quarantine said experts from the Health Ministry had deemed diethylene glycol a "low-level" poison that does not accumulate in the body and found no evidence the substance caused cancer or deformities.

It also said European Union standards allow for a certain amount of the chemical and cited a 2000 Chinese study that found toothpaste containing less than 15.6 percent diethylene glycol was not harmful. The Chinese toothpaste the FDA is concerned about contains between 3 percent to 4 percent of the drug, according to the FDA.

"Therefore the warning issued by the FDA ... is unscientific, irresponsible and contradictory," the agency said.

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

The FDA alert Friday said the agency found diethylene glycol, or DEG, in three products manufactured by Goldcredit International Trading in China: Cooldent Fluoride, Cooldent Spearmint and Cooldent ICE.

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

Phones at both companies rang unanswered Sunday.

Companies that make brands previously found with DEG will have to prove the toothpaste is free of the chemical before it's allowed into the U.S., the FDA said. Meanwhile, all other brands of Chinese-made toothpaste will be stopped for testing, something the FDA has been doing since May 23.

A slew of Chinese exports have recently been banned or turned away by U.S. inspectors including, wheat gluten tainted with the chemical melamine that has been blamed for dog and cat deaths in North America, monkfish that turned out to be toxic pufferfish, drug-laced frozen eel, and juice made with unsafe color additives.

DEG was blamed for the deaths of 51 people in Panama after they took tainted cold medicine. China has admitted it was the source of the deadly chemical but insists it was originally labeled as for industrial use only.

Officials in Panama and several other Latin American countries have removed tens of thousands of tubes of Chinese-made toothpaste from stores amid concerns that they contain DEG.