Some excerpts from this article from the Gadsden Times, 30 Nov 2004:

Many police officers say that Tasers give them a way to restrain dangerous suspects without using firearms or fighting with them. But civil liberties groups say police often use Tasers on people who are merely unruly or disobedient, not dangerous. Recently, police officers in Miami shocked a 6-year-old boy and a 12-year-old girl in separate incidents, prompting widespread criticism.

The growing use of Tasers is disconcerting because their risks have not been properly studied, biomedical engineers say. More than 70 people have died since 2001 after being shocked with Tasers, mainly from heart or respiratory failure.

Taser International says the deaths resulted from drug overdoses or other factors and would have occurred anyway. But coroners have linked several deaths to the weapons, and independent scientists who are authorities on electricity and the heart say that the company may be significantly underestimating the weapon's risks, especially in people who have used drugs or have heart disease.

Taser has performed only minimal research on the health effects of its weapons. Its primary safety studies on the M26, its most powerful gun, consist of tests on a single pig in 1996 and on five dogs in 1999. The company has resisted calls for more tests, saying that it is comfortable with the research it has conducted.

But last week, after the symposium on less-deadly weapons in Winston-Salem, N.C., the Air Force laboratory that conducted the study said that it had not found Tasers were safe.

The guns "may cause several unintended effects, albeit with estimated low probabilities of occurrence," the laboratory said. "Available laboratory data are too limited to adequately quantify possible risks of ventricular fibrillation or seizures, particularly in susceptible populations."

An Air Force scientist presented data at the symposium last week showing that repeated Taser shocks caused pigs to become acidotic - a dangerous condition in which the pH of the blood drops. A 1999 study by the Justice Department suggested that "deaths following Tasers' use may be due to acidosis."

People who have been hit repeatedly by Tasers should receive medical monitoring, said Dr. James Jauchem, the Air Force scientist.

I still say that people who are issued these things ought to be shocked with them first, if they're so safe. It would give the carriers a personal datapoint concerning the effects. This is not Star Trek.

Would you trust the safety of a product intended for humans that had been tested on one pig and five dogs?