COLUMBIA -- Three South Carolina Highway Patrol officers have been hurt in Taser training incidents this year.

One of the three is still not on the job and drawing workers' compensation for injuries, said S.C. Department of Public Safety director Mark Keel.

Those three injuries are out of some 300 troopers trained during that time.

During roughly eight hours of Taser training, each officer gets Tased to learn what the 7-ounce, black and yellow gun used to subdue suspects can do.

"It is the most pain I ever felt in my life, from my head to my toes and everything -- and I mean everything -- in between," said Richland Sheriff Leon Lott, who wanted to see what he was asking his deputies to do.

"I felt like my muscles were going to explode," Lott said.

Tasers shoot out two electrically charged miniature fishhooks attached to wires that travel 200 feet per second. The hooks impale themselves in flesh or clothing, penetrating all but the thickest clothes. Both hooks have to attach themselves to flesh or clothes before a charge can be delivered through the lines.

Shooters normally fire 5-second bursts but can control the duration of the shock. They may fire more than once.

The muscles of a Tased person contract. Losing control of his muscles, he falls to the ground and stays immobilized long enough to be handcuffed.

Law enforcement agencies like to say that the Taser is an alternative to a baton or tear gas for subduing a suspect. But, effectively, a Taser is an alternative to a gun when it prevents a situation from spiraling out of control.

How dangerous they are has been debated since law enforcement agencies began wide use of the weapons in the past five to10 years.

Citing medical privacy rules, Keel would not discuss how the three South Carolina troopers got hurt or the severity of the injuries.

According to the Taser International company that makes the guns, some 1.1 million officers and volunteers have been Tased in training situations since the mid-1990s. Very few have been injured, a company spokesman said.

Officers undergoing training are Tased under highly controlled circumstances. They aren't fighting back, and they are supposed to be held so they won't fall and hurt themselves.

Agencies train their own employees after sending select officers to the Taser company's headquarters in Arizona. Those officers learn how to use the weapon and how to teach Taser use to their fellow officers.

The S.C. Criminal Justice Academy, which provides training for law enforcement officials across the state, does not provide Taser training.

Law officers defend their use as a way to subdue violent subjects before violence escalates to a point where an officer might fire his gun.

But Tasers have drawbacks.

Last month in Greenville, for example, a mentally ill man resisting arrest died after being Tased by city police officers. The county coroner ruled that being Tased was one of several factors -- including an enlarged heart -- that caused the man to die. The State Law Enforcement Division is investigating.

The Taser company does not contest findings that the weapon has been a contributing factor about 20 deaths in real-life police situations since 1993. But the company says the deaths are unusual, considering there have been more than 1 million on-the-job Taser firings in that time period.

Spokesman Steve Tuttle said misconceptions about the Taser give many people the impression that the weapon seriously injures or kills far more people than it actually does. Investigations usually clear the Taser as being at fault for a death that occurs after its use, he said.

"We're like the airline industry. You are going to have some accidents, but you also have 10,000 safe landings every day," Tuttle said.

Tuttle cited a 2007 federally funded study of 597 Taser subjects taken into police custody who were immediately checked by medical personnel. It found:

Seventy-seven percent, or 458 people, had no injuries. Twenty-three percent, or 136 people, had mild injuries. These included puncture wounds and cuts.

One-half percent, or three people, were injured seriously enough to be admitted to a hospital.

In other words, 99.5 percent of 597 people Tased had no injuries or mild injuries, the study said. No one died.

Critics, however, contend the company minimizes risks to life and health, understating the dangers the electrical charges pose to the heart's delicate electrical circuitry and back muscles.

Critics also cite numerous anecdotes, such as a widely publicized Montana case in May in which a 32-year-old deputy, Jason Frederick, had to undergo surgery after breaking both arms and shoulder sockets in a Taser training accident.

The vibrations of Frederick's muscles broke his bones, news accounts said.

DPS director Keel said that although troopers have long had tear gas and batons, the gas sometimes doesn't work, and whacking someone with a baton doesn't look humane, he said.

Often, all a trooper needs to do is draw the Taser to defuse a situation, Keel said.

"When you pull that Taser out, and you holler, 'Taser! Taser! Taser!,' and you are getting ready to light somebody up, a lot of times you get immediate compliance," Keel said.

In 2007, before its wide use of Tasers, the Highway Patrol had 109 "use of force" incidents. In 2008 and 2009, that number dropped to 76 incidents, in part due to stricter management of troopers and in part, Keel said, due to Tasers.

Keel said he considers the three Taser injuries this year a regrettable but acceptable risk.

In February of this year, using a federal grant, the patrol bought 300 Tasers at $825 each. In June, it bought 18 more. With more than 300 additional troopers trained this year, Keel said he is hoping for a further drop in "use of force" incidents.

While law enforcement agencies say they have Taser use under control, others are watching closely.

Victoria Middleton of the South Carolina office of the ACLU warned that Tasers can endanger vulnerable people, such as the elderly, disabled and pregnant women. Law agencies need "clear protocols" and proper training before deploying Tasers, she said.