BEIJING — China is stepping up controls on dental care products, state media reported Wednesday amid international alarm over Chinese toothpaste producers' use of a potentially toxic chemical found in antifreeze.

Countries in North and South America, as well as Asia, have recently halted imports of Chinese-made toothpaste due to its content of diethylene glycol, a low-cost and sometimes deadly substitute for glycerin. However, there have been no reports of health problems stemming from the product. China has no guideline banning the chemical in toothpaste, and the government says it is harmless in small amounts.

The toothpaste is one of series of apparently tainted Chinese exports that have sparked fears the Asian country's chronic domestic product safety problems are turning into a global scourge. On Tuesday, China's food safety watchdog reported on problems with nearly a fifth of products made for domestic consumption in the first half of this year.

A set of "strict certification and evaluation procedures" are being drawn up for oral care products by China's Health Ministry and the China Certification and Accreditation Administration, the China News Service said, citing an announcement made during a national symposium.

The certification administration's Web site said the new rules would "improve the quality, safety and hygiene of oral health care products." It was unclear how the rules would treat diethylene glycol.

A spokeswoman for the administration, which oversees the certification of Chinese products, confirmed the regulations were being drawn up and said the administration had asked for public opinions last year. Like many Chinese bureaucrats, she declined to give her name.

Also Wednesday, China's Ministry of Health announced a recall of two brands of diapers spot checks found to contain excessive fungus. Authorities did not say if the diapers, made in the northern province of Hebei, and in Fujian province in the south, and sold under the brand names Haobeir and Jinglianbangshuang, had been exported or if they had caused problems for any children.

Worries over the safety of Chinese exports began earlier this year, when the deaths of dogs and cats in North America were linked to pet food containing Chinese wheat gluten tainted with the chemical melamine.

Since then, U.S. authorities have also banned or turned away a long list of Chinese products, including toxic fish, juice containing unsafe color additives and popular toy trains decorated with lead paint.

Chinese authorities at first played down or ignored international concerns, and have reacted defensively by highlighting problems with imports from other countries.