Experts dispute data on stun guns
Taser International said its weapons were a safe way to subdue children, but some researchers say more study is needed.
BY LISA ARTHUR, SUSANNAH A. NESMITH AND JACOB GOLDSTEIN, Miami Herald
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Taser International calls the outcry after Miami-Dade police zapped two children with its stun gun unjustified -- the company says it has the science to prove the weapon is safe for use on kids.
But researchers, doctors and one of the world's most respected independent testing labs dispute various elements of Taser's data and say more research is needed.
-= Taser uses a chart in its training manual that says its weapon delivers a shock well below a threshold that Underwriters Laboratories (UL) has deemed safe for a 2-year-old.
But some UL scientists question the application of their study to Tasers.
''For them to say that Taser is safe based on that line, I don't accept that,'' said Walter Skuggevig, a research engineer at UL for 41 years who has done extensive study into electric shock injury. ``It's not an appropriate limit for that kind of product.''
-= In its literature, Taser cites several animal studies it sponsored that it says show the gun is safe for kids.
But a lead researcher on those studies said he didn't design the experiments with kids in mind.
''I don't know that I had ever envisioned the use of this thing on small children,'' said Wayne McDaniel, a University of Missouri-Columbia electrical engineer who ran the Taser studies. ``I don't think anyone has ever tried to draw any inferences as far as use in children . . . The design of this device is for bad guys.''
-= Taser cites independent studies done by several countries and the U.S. Department of Defense as proof that the gun poses no serious hazards.
CONCERN FOR EVIDENCE
But doctors and researchers say there's not enough evidence about the potential effects on kids to make such a blanket statement, especially concerning children.
''I don't think anybody really knows what the risks are using them with people,'' said Kenneth Foster, a bioengineer who reviewed research on Tasers for the Defense Department, which bought the stun guns to use in Iraq and Afghanistan. ``There's no data whatsoever to justify saying there are no risks.''
Taser insists its product is safe.
''While there's room for scientific debate as to which safety standards best apply, we believe the field proven safety record of the Taser nonlethal device is unparalleled,'' Taser said in an e-mailed statement. ``Taser International is committed to further expanding the research in the field of Taser device safety.''
The debate on the safety of zapping kids drew national attention last month after reports emerged that Miami-Dade police jolted a 6-year-old boy and a 12-year-old girl.
Thousands of police officers across the country carry Tasers and hail the gun as one of the safest ways to subdue violent people.
Nationwide, there have been a number of incidents of children being shocked with the gun since 1998.
Some 1,700 cops and school resource officers carry the weapon, according to Taser. Miami-Dade school police don't have Tasers, and school officials have asked county police not to use them in elementary schools and only as a last resort on older students.
There are no known reports of a child dying or suffering serious injuries after a jolt. Roughly 100,000 adults voluntarily have been zapped with the gun, Taser says. None of the volunteers -- mostly cops -- died or suffered serious injuries.
UNIQUE RISKS FOR KIDS
Some experts say the anecdotal evidence has some merit, but they are troubled by the lack of scientific research.
''If you shoot a couple thousand people and no one dies, you would guess that the risks are probably pretty low, but that's not really research,'' said Foster, who was on the defense department review panel and is a professor at the University of Pennsylvania.
He said the panel didn't examine Taser use on kids. ``It was never imagined that this would be used with children.''
Several experts say Tasers may pose unique risks for kids.
''Kids are going to be more at risk because they're smaller. That means the current is going to be more intense,'' said Roger Barr, a Duke University biomedical engineer who studies how electricity affects the body. Barr said kids could suffer nerve or muscle damage from being shot with a Taser.
Taser disputes that, saying children would be at lower risk for injury.
''A child's muscles are not as strong, and are therefore less likely to cause contraction-related damage,'' the company said in its statement.
They discount nerve injury as a risk.
Taser insists its research clearly shows zapping a 55-pound child -- the weight of the 6-year-old shocked by Miami-Dade officers -- falls well within safety margins.
''The McDaniel study used animals with a range of body weights, including subjects below 70 pounds,'' Taser said in its statement. ``While the test protocol was not designed specifically for children, the data yields important safety information indicating a significant 15-to-1 safety margin in body weights as low as 66 pounds.''
A 15-to-1 safety margin means that researchers found that a pig's heart did not develop an irregular rhythm until a shock 15 times as strong as a Taser's jolt was administered.
That study is set to be released in a peer-reviewed journal in Jan. 2005, Taser said.
Taser points to the Defense Department study as a strong endorsement of the gun. That study, to be published soon, concluded stun guns are ``generally safe.''
But the study called for more research because there isn't enough data available about possible risks ''in susceptible populations,'' said Larry Farlow, spokesman for the Texas-based Air Force Research Laboratory, which conducted the research.
Independent studies done by authorities in England and Canada reached a similar conclusion: Tasers are safe enough for police to use, but more research is needed.
IRREGULAR HEARTBEAT
Most of the studies cited by Taser examine whether a jolt from the gun will cause a potentially deadly irregular heartbeat in adults.
Taser includes a line graph in its literature that shows UL shock limits that will cause the heart to stop, and notes the safety margin was calculated for humans from 2 to 75 years old. The jolt of the Taser model used by Miami-Dade police is plotted well below that level.
The shock limit in the chart is based on a 1939 study done by UL, the 110-year-old lab whose approval label appears on more than 19 billion products. The study established the largest jolt a human who touched an electrified cattle fence could endure without risking a potentially deadly irregular heartbeat.
The study has been updated eight times, most recently in 2003, as new cattle fences have been developed.
''It doesn't apply to that kind of product,'' UL's Skuggevig said, referring to Tasers.
UL spokesman Paul Baker said the lab didn't know its research was included in Taser's literature until The Herald asked him to review the safety manual.
''We certainly don't want to give the impression that we put our label on this, that we certify this,'' he said. ``We do not.''
Gary Bowling, a training officer for the Putnam County Sheriff's Office, said he left a Taser seminar thinking UL endorsed Tasers. He said the UL name convinced him that he could ``Taser a 4- to 400-year-old, if necessary.''
''I trust UL,'' Bowling said. ``I treat that chart as gospel.''
When told by The Herald that UL had not tested the product, Bowling said, ``That chart's misleading. I looked at that and I thought UL had tested Tasers and put that dot on the chart.''
Still, he believes Tasers are safer than pepper spray, batons or rubber bullets.
Taser Vice President Steve Tuttle said in a statement released Saturday that the company's faith in the safety of Tasers is not based solely on the UL limit.
'It is important to realize that Underwriters Laboratories' guidelines were not the end result of Taser safety testing, but were the beginning,'' he said. ``Since that time, Taser has garnered additional research from both the medical and scientific communities specifically addressing Taser-type pulses.''
Tuttle added: ``Taser International has never claimed that UL has tested or approved Taser devices, although we invite and welcome them to test our products.''
In response to Taser's statement, UL's Baker reiterated that UL can't say whether Tasers are safe or not because the lab hasn't tested them and at this time has no plans to do so.
''We're pleased that Taser has now clarified that its products have never been tested or certified by UL,'' said Baker.
The UL research cited by Taser doesn't necessarily pertain to stun guns, Skuggevig said last week.
THE FLOW OF SHOCK
The UL electrified cattle fence studies assume that a single electric shock flows from a person's hand through the feet.
The 50,000-volt Taser shoots out two wires tipped with barbed probes and delivers a standard dose of 15 electrical pulses per second for 5 seconds.
The route the current takes through the body varies depending where the probes land.
If the probes embed themselves in a person's chest, for example, Skuggevig said ``that could be more dangerous . . . especially if the electrodes are near the heart.''
Dr. Robert Stratbucker, Taser's medical director, said in an e-mailed statement that the gun's electric current travels a path just under the skin and that ``very little of this current reaches internal organs such as the heart.''
But Dr. William Bozeman, a professor of emergency medicine at Wake Forest University who has studied Tasers, said it remains unclear exactly where Taser's charge goes.
Researchers are studying ''the pathway that the current takes -- whether it's across the skin of the body, through the muscle tissue or across other tissues,'' he said. Bozeman said the Taser appears safe to use on adults, but its effects on small children are less clear.
''Reasonable extrapolation by doctors like me would say that within some limits, it's probably OK -- at least safe and not likely to injure the person -- as long as the person is not terribly small,'' he said. ``I don't have a clear age or weight limit here.''
Staff Researcher Elisabeth Donovan contributed to this report.
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