Canadian health officials announced Saturday that bisphenol A is toxic and said they will ban baby bottles made with the chemical.

The move, a first by any country, is giving fuel to those who want the chemical, found in plastic baby bottles and in the linings of cans, declared dangerous in the United States and elsewhere.

Canadian regulators will begin writing rules prohibiting the sale, import and advertising of the chemical in baby products. Those bans likely will begin in 2009, according to Health Canada, the federal health agency. Canada’s action is directed only at products for young children. The health officials found no cause for concern in older children or adults.

Scientists concerned about the effects of the chemical said Saturday’s action is likely to lead to restrictions in the United States.

“Luckily, the action by the Canadian government is already having a ripple effect in the U.S.,” said Frederick vom Saal, a researcher at the University of Missouri who has studied the effects of the chemical for more than a decade. “Thank goodness for our neighbors to the north who, unlike our political leaders, were willing to pay attention to the science demonstrating that bisphenol A poses a threat to the public health, particularly when exposure occurs during development.”

The American Chemistry Council, which represents makers of bisphenol A, did not issue a statement Saturday on Canada’s action. Spokeswoman Tiffany Harrington said a response is expected in the next few days.

Sonya Lunder, senior analyst with the Environmental Working Group, a nonprofit environmental research organization based in Washington, D.C., said she expects companies that sell in the United States to begin phasing out use of bisphenol A because marketing products to specific areas is too costly.

“I think we’ll see American kids protected by the actions of the Canadian government,” she said.

Bisphenol A, developed as an estrogen replacement, is used to make hard, clear plastic. It’s used commonly in baby bottles, the lining of food and beverage cans, CDs, eyeglasses and dental sealants. Studies in the past several years have linked it to cancer, heart disease, obesity, reproductive failures, autism and hyperactivity in laboratory animals. Unlike other chemicals whose toxic effects tend to increase with the dose, the effects of bisphenol A have been found at extremely low doses.

Studies have shown the main sources of exposure for newborns and infants are from bisphenol A migrating from the linings of cans into liquid infant formula and migrating from polycarbonate baby bottles into the liquid inside after the addition of boiling water. Bisphenol A has been found in the urine of 93 percent of people tested in the United States.

Chemical makers are watching the decision carefully. Last year, sales of bisphenol A topped $6 billion worldwide.