Sold as 'non-lethal,' Tasers killed 400 in US, Canada since 2001
They are marketed as non-lethal weapons that allow police to capture suspects or criminals without causing any permanent harm.
Former New York Mayor Rudolph Giuliani and businessman Bernard Kerik made millions selling the idea to police departments across the country.
But Tasers have killed more than 400 people in the United States and Canada since 2001, according to a new study commissioned by the Canadian Broadcasting Corp.
Police departments across Canada began banning use of Tasers by their officers after the report found that Tasers deliver more power than the manufacturer says is possible.
It is unknown if U.S. police departments will follow suit.
The study includes a medical analysis that concluded someone shot with a Taser could face as high as a 50 percent chance of cardiac arrest.
The Taser company, however, still says its weapons can't kill.
"It is unfortunate that false allegations based on scientifically flawed data can create such uncertainty," Steve Tuttle, a Taser vice president, told The Arizona Republic.
Stories of Taser-related deaths have stacked up over the years, many involving police officers who never realized the harm their Taser could cause.
A man described as "emotionally disturbed" fell to his death after police Tasered him on a fire escape. Not long after, the officer who gave the order took a Glock 9mm from the locker room and shot himself in the head.
Earlier this week, police Tasered a man who had gone into Diabetic shock while driving. The officers later said they felt "extremely bad" about shocking him when they realized he wasn't drunk or high but in need of medical attention.
"Taser's marketing coup has been to convince consumers that there is such a thing as a gun that won't kill," AlterNet reported.
On the Taser Web site, a marketing slogan reads: "Who says safety can't be stylish?"