Quebec is now the lone holdout among the provinces.
It is now up to local police services in Ontario to decide whether they want to equip all their officers with stun guns, which are currently restricted to supervisors and specialists, such as tactical units and hostage rescue teams.
Police forces will also have to foot the bill if they want to arm their officers with Tasers — costing about $1,500 each — which will put pressure on municipal budgets.
Ontario police chiefs and associations have been pushing the government for years to expand the use of stun guns, to no avail. Coroner's inquests have also recommended expanding the use of stun guns since 2004.
But the governing Liberals insist the Sammy Yatim's death had nothing to do with their change of heart, even though the announcement was made on the one-month anniversary of the fatal police shooting.
The decision came after "extensive consultation" and was supposed to be announced in June, Community Safety Minister Madeleine Meilleur said Tuesday.
But she's not waiting for a report by Ontario's ombudsman, who has launched his own probe of the province's direction to police about defusing conflict situations.
Meilleur wouldn't say whether Yatim's death could have been prevented if Ontario had made the change sooner.
"It was not a decision that was taken lightly," she said. "We have all seen what happened at the airport in Vancouver."
Polish immigrant Robert Dziekanski died in 2007 after being stunned with a Taser at the airport by RCMP officers.
But Meilleur said studies have shown that using Tasers can reduce injuries by 60 to 65 per cent.
Ontario's interim chief coroner and many police groups support the government's decision. Chief forensic pathologist Michael Pollanen said it's "unusual and quite rare" for someone to die after being stunned by a Taser and there's no clear evidence that it's the primary cause of death.
But Marcus Firman, whose mentally ill son Aron died in 2010 after being stunned by a Taser, said the province should be funding mobile police crisis teams, rather than expanding the use of a potentially lethal weapon.
He said he fears more people will die like his son.
"I would say it's a knee-jerk reaction basically to the Sammy Yatim issue, they feel that they have to react," he said.
"But it's about reacting appropriately. I think they're actually jumping the gun here."
In Yatim's case, the supervisor stunned a teen "with eight bullets in him," said Firman's lawyer, Julian Falconer.
"So our response? Give the Taser to more people," he said. "This is Alice in Wonderland."
North Bay police chief Paul Cook, who also serves as president of the Ontario Association of Chiefs of Police, said there are times when simply showing a Taser can defuse a dangerous situation. It also gives officers a less lethal option.
In one case, police were able to use a stun gun to apprehend a man who was trying to get them to shoot him, he said. If they hadn't had the stun gun, they would have been forced to use their sidearms.
Last year, the 97-member police force deployed stun guns 11 times and fired them only three times, he said. No one was injured or killed.
There are risks to any use of force and money is an issue, Cook said. But providing stun guns to more cops is "absolutely the right thing to do."
The Police Association of Ontario is urging all police forces to start training and equipping frontline cops with stun guns.
The Ontario Provincial Police and Toronto Police Services say they'll make them available to some frontline cops, along with the gun, extendable baton and pepper spray that are currently at their disposal. Ottawa and Hamilton police are also planning to expand the use of Tasers.
Frontline OPP officers will likely be equipped with Tasers within two years, said deputy commissioner Vince Hawkes.
The training takes eight months, but Meilleur said it will be extended to 12 months. Officers will also have to report when they even display a stun gun.
"We're going to study who needs it based on a priority basis, so that the frontline officers dealing with the public in those violent situations can get the Taser first, versus some of the others," Hawkes said.
Finding the money amid the high cost of policing will be an important issue as well, he said.
The government is simply passing the buck by refusing to pay for the stun guns, said Windsor Mayor Eddie Francis.
Police forces who can't afford Tasers could be blamed if there's an incident that may have been prevented by the use of a stun gun, he added.
"If you feel that it's important and you believe in it, why are you not funding it?" Francis told Windsor radio station CKLW.
The use of force by police in Ontario has come under scrutiny after Yatim, 18, was shot multiple times and Tasered by police during a confrontation on an empty streetcar.
Videos of the incident prompted hundreds of people to take to the streets to demand justice.
The Special Investigations Unit has charged Toronto police Const. James Forcillo with second-degree murder.
Retired justice Dennis O'Connor has been asked by Toronto police chief Bill Blair to lead a separate review of police procedures, use of force and police response to emotionally disturbed people.
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