Some Tasers deliver a higher level of electricity than the manufacturer promises, reveals a series of tests on 41 stun guns that was commissioned by CBC News and Radio-Canada.

Three of the X26 Tasers tested by U.S.-based lab National Technical Systems as part of a CBC/Radio-Canada investigation into the devices. (CBC)

The abnormal X26 model Tasers were manufactured before 2005, prompting some scientists to suggest police should stop using any older versions of the stun guns until they can be tested.

Of the 41 Tasers tested, four delivered significantly more current than Taser International says is possible. In some cases, the current was up to 50 per cent stronger than specified on the devices.

The tests, conducted by the U.S.-based lab National Technical Systems, used X26 Tasers from seven police departments in that country. Each weapon was fired at least six times.

Arizona-based Taser International makes virtually all the stun guns being used by police forces. The technical term for a stun gun is conductive energy weapon, or CEW. They are intended to incapacitate people with an electric shock.

The RCMP says it has pulled a random sample of some of the forces' Tasers for testing based on the results of the CBC News/Radio-Canada investigation.

"Given that you have raised this issue with us, we are taking steps to take CEWs out of our inventory devices that have deployed across the country, we are gathering up samples from each of our divisions, every province and every territory and we will have them independently tested," RCMP Commissioner William Elliott told CBC News at a recent policing event.

A force communications official, Supt. Tim Cogan, informed CBC News late Thursday that preliminary test results showed the sample of Tasers operated within the manufacturer's specifications.

Cogan said the tests were conducted at an accredited, independent laboratory in Ottawa, but didn't provide details on how many Tasers were tested or which lab conducted the analysis. The RCMP is still awaiting final test results.

"The RCMP recognizes that any use of force, including the CEW, carries risks, both to the public and to the police," Cogan said in a letter to CBC News.

"We do not take the use of force lightly. Ongoing assessment of the tools provided to our members and of the policies that guide their use is essential to mitigate these risks."

Pierre Savard, a biomedical engineering professor at École Polytechnique de Montréal, designed the technical procedure for the CBC's testing based on Taser International’s specifications.

Savard told CBC News it is scientifically significant that about nine per cent of the Tasers fired in the tests delivered more current than they are supposed to do, especially since he believes no one is verifying the company’s claims.

"I think it's important because Taser is not subjected to international standards," Savard said.

"When you use a cellphone, well, cellphones have to respect a set of standards … for the electric magnetic field that it emits. The Taser, well, nobody knows except Taser International."

Savard said the cause of the increased current could be either due to faulty quality control during the stun guns' manufacturing or electrical components that deteriorate with age.

The findings are troubling, since police officers are trained to aim a Taser at the chest, said Savard, who studies heart rhythms and how they are affected by electrical stimulation.

"When you combine an increased current intensity with a dart that falls right over the heart for somebody who has cardiovascular disease or other conditions such as using drugs, for example, it can all add up to a fatal issue," Savard said.

Malfunctioning Tasers

One of 44 X26 Tasers provided for testing by seven police departments in the United States. (CBC)Police forces across North America assure people that Tasers are safe. The manufacturer, Taser International, has said its product has a higher safety margin than Tylenol.

Taser International said they couldn’t provide someone for an interview before the CBC published results from the tests.

However, Magne Nerheim, Taser's vice-president of research and development, sent a written response to the results, in which he called the four malfunctioning Tasers an anomaly — one that could be explained if the weapons are not spark tested on a regular basis.

Nerheim also suggested the testing be repeated to verify the results. He made no comment about the age of the Tasers and whether there could be an issue of reliability.

During the tests commissioned by CBC News and Radio-Canada, three of the weapons didn't fire, even with charged battery packs. Those were set aside and not counted in the final results.

But a Taser that doesn't deploy can potentially create a safety issue for a police officer, Savard said.

"When we are talking about Tasers that don’t function, I think it is dangerous for the policeman who would try to use the Taser and the individual response can be aggressive," he said.

The CBC showed the results to several electrical engineers as a peer review of the analysis. They agreed that at the very least, the Tasers made before 2005 should not be used again until they are tested and proved reliable.