TORONTO - Ontario joined Quebec in banning the sale and cosmetic use of pesticides Wednesday, but critics say the move will actually weaken existing anti-pesticide rules across the province.

The ban was the last government-backed bill to be rammed through before the legislature adjourned for the summer, passing 56-17 over the objections of health groups and municipalities.

More than 80 ingredients and 300 pesticide products will be prohibited once the ban is fully implemented next spring, which supporters say will give Ontario the toughest rules in North America.

It's even looking at banning the herbicide 2,4-D, which has been deemed safe by Health Canada.

"All of us, including young children, deserve to be able to walk in the park and enjoy all the gardens, and watch themselves and their parents playing outdoors without worrying about the unnecessary risks of pesticides," said Environment Minister John Gerretsen.

Experts, such as the Ontario College of Family Physicians, have warned that the long-term effects of exposure to pesticides can be devastating, especially to pregnant women and children.

The province will only allow pesticides to be used in farming, forestry or for health and safety reasons, such as controlling mosquitoes that can carry diseases like the West Nile virus.

Golf courses will also be able to use pesticides, but must meet certain conditions to minimize the effects on the environment - regulations that haven't yet been drafted.

According to Peter MacLeod of CropLife Canada, a pesticide industry association, lawns and gardens represent only about four per cent of the pesticide business across Canada.

Unlike Quebec, Ontario municipalities are forbidden from enacting tougher anti-pesticide rules.

In announcing the ban in April, Premier Dalton McGuinty mistakenly said towns and cities could have stronger bylaws if they wanted to, a move many applauded.

Two weeks later, McGuinty admitted he "screwed up," but shifted the blame to Environment Minister John Gerretsen, who failed to correct the premier at the time.

The government's refusal to amend the legislation has angered some municipalities and health groups.

Toronto is considering taking legal action to challenge the provincewide ban, which doesn't include Roundup, a prohibited pesticide under municipal bylaws.

Erin Shapero, a councillor in Markham, said she'll be talking to lawyers as well.

"The premier got it right when he got it wrong," she said.

"Deep down in his heart, I know he knows that. And it's just unfortunate that the legislation that passed today doesn't reflect his true wish."

The bill drew some support from the Progressive Conservatives but was panned by the province's 10 New Democrats.

When the legislation went to committee, the Liberals voted down amendments that would have allowed municipalities to retain their power to enact tougher rules, said NDP critic Peter Tabuns.

As a result, municipalities will be stripped of their ability to protect the health of their residents and may be forced to spend a lot of money and time fighting the province in court, he said.

"This government should not put municipalities through this," he said.

"Municipalities are pioneers. They've shown the way forward on smoking, on the environment, and to reduce their powers like this doesn't make any sense."

Others who were among a coalition of environmental activists and health professionals that banded together to lobby for a pesticide ban, withdrew their support Wednesday.

"We ... applauded what we thought was a step forward to protect people from these poisonous chemicals," Wendy Fucile, president the Registered Nurses' Association of Ontario, said in a statement.

"But today, we see what the province's legislation actually means is that municipalities will be stripped of their tough municipal bylaws to protect people, and the provincial legislation will serve as a ceiling, not as a floor upon which stronger local regulations can build."

The governing Liberals just wanted to grab headlines, rather than coming up with a ban that was based on real science, said Progressive Conservative Leader John Tory.

"They've done something that's been motivated more by political science," he said.

"I think it's just another attempt to curry a headline and take away from the real issues."

Gerretsen acknowledged that "a lot of hard work" still has to be done in drafting regulations, but pledged to work with municipalities to get it done right.