Ontario should take a proactive step and become the first Canadian province to ban potentially toxic plastic baby bottles, rubber duckies and other children's toys to reduce the chance of cancer in adulthood, environmentalists and parents said Monday.

Health Canada is now studying the impact of Bisphenol A, a chemical that is used in everything from plastic children's bath toys to sippy cups. The Ontario government, which is planning to ban several toxins, says it takes the concerns "very seriously."

With environmentalists, parents and children's activists scheduled to rally Tuesday at the Ontario legislature to push the province into action, an American expert on the chemical said the province's Liberal government ought to ban the substance without waiting on Ottawa.

"Ontario should take action now," said John Peterson Myers, CEO of Environmental Health Sciences in Virginia. "The science that has come in is sufficiently disturbing that waiting to have confirmation based on years of epidemiological research is simply unacceptable."

There is little scientific evidence on what Bisphenol A does to humans, Myers said. But studies on mice and other animals with lower levels of the substance link the chemical to the development of cancer, reproductive problems, Type 2 diabetes and learning development disorders, he said. "We're very concerned about that," Myers said.

That concern is shared by some parents and environmentalists. Rick Smith, executive director of Environmental Defence, said his young sons used to read — and, as children are prone to do, chew — plastic inflatable books in the bathtub before he realized they were made with Bisphenol A.

The chemical is unnecessary and it's too important for Ontario to leave in the hands of the federal government, Smith said. No other province is considering a ban on the substance, but Smith said other U.S. states have phased out similar toxins, like fire retardants.

San Francisco instituted ban in 2006

Last year, the city of San Francisco banned the sale, distribution and manufacture of baby products containing Bisphenol A. Spearheading a similar ban in Ontario should be the Liberal government's top priority when the legislature reconvenes next week, Smith said.

"What the heck is the hold-up?" Smith said. "These are not absolutely irreplaceable chemicals. Surely it's the government's job to make sure — if there is any possibility that these chemicals are causing a problem — that they are yanked from the marketplace."

The Liberals, re-elected in October to a second mandate after a campaign that included pledges to ban cosmetic pesticides and crack down on environmental pollutants, are indeed looking for ways to lead the charge, a government source said Monday.

The Liberals will likely ban pesticides first, but intend to appoint an expert panel to examine which chemicals should be targeted by toxin reduction legislation, the source said.

Health Canada spokeswoman Joey Rathwell said the ministry is currently reviewing Bisphenol A and expects to have a report ready by May 2008. The report will examine how much of the chemical is used, the impact it has on human health and whether action is required, she said.

Previously, Health Canada had said bisphenol A didn't pose a risk.