Steve Butler was shocked with a stun gun fired by a Watsonville, Calif., police officer when Butler refused to get off a Metro bus on Oct. 7, 2006, but has no recollection of the moment that changed his life forever.

SANTA CRUZ, Calif. — Steve Butler knows Barack Obama is president, but that's only because Butler has heard the information so many times.

Butler also knows he was shocked with a stun gun fired by a Watsonville, Calif., police officer when Butler refused to get off a Metro bus on Oct. 7, 2006. But he has no recollection of the moment that changed his life forever.

The 51-year-old has no short-term memory, one aspect of a brain injury he suffered when he was hit with the stun gun darts, went into cardiac arrest and was deprived of oxygen for 18 minutes, according to his attorney, Dana Scruggs of Santa Cruz, Calif.

But whether the electric shock is to blame for Butler's heart failure is the point of contention in a lawsuit Butler filed against the stun gun maker TASER International seeking lifetime medical care, and the crux of a larger debate about the safety of the weapons, which are used by all police departments in Santa Cruz County and are standard issue for thousands of other law enforcement agencies throughout the country.

San Francisco's Police Commission rejected a proposal to draft a policy for the use of Tasers by officers Wednesday because of concerns about the safety of stun guns. It was the second time in two weeks the commission has denied the plan, which the police chief said would reduce officer injuries, save suspects' lives and decrease the city's litigation costs.

Both perspectives have support:

More than 350 people have died after being shocked by police Tasers in the U.S. between 2001 and 2008, according to figures gathered by the international human rights group Amnesty International. A U.S. Department of Justice-funded review of more than 4,000 uses of Taser ECDs, or electronic control devices, found "serious injuries are clearly rare, and there are no cases in any of the reports suggesting sudden cardiac death related to the TASER," according to a TASER company document.

Butler will ask a Santa Cruz County jury to decide his case later this month, assuming a judge does not side with a TASER International motion to dismiss the case, which will be heard Wednesday.

A spokesman for TASER International declined to answer questions, but released a three-page document addressing the Butler case.

In it, the company states that Tasers are not a risk-free but that the devices "have among the lowest risk of injury of any modern force option."

Scruggs said Tasers can be useful for law enforcement, but that the weapons have side effects and manufacturers need to be up-front with police about the risks.

"We believe this is a case of corporate fraud," Scruggs said, explaining that Watsonville police and other law enforcement agencies may have been misled by training materials that told officers "to shoot people in the chest and there were no cardiac risks to doing so."

The police were as much of a victim as Butler in the situation, according to Scruggs.

Watsonville Police Chief Manny Solano said his agency had a Taser-use policy in place prior to the October 2006 incident and that the policy has not been significantly altered. However, a training bulletin issued by TASER International in September 2009 advised stun gun users to avoid intentionally targeting the chest, according to a company document.

Butler has admitted he was drunk and misbehaving when officers asked him to exit the bus. He also had a history of mental illness and had been taken off his medication a couple months prior, Scruggs said.

After he was shocked, Butler lost consciousness and stopped breathing, and officers called for firefighters and paramedics. Butler was resuscitated on the way to the hospital.

The company claims Butler had a pre-existing cardiac condition and had a blood-alcohol level more than four times the legal limit of 0.08 and marijuana in his system when he was rushed to Watsonville Community Hospital after the altercation with police, according to the TASER International statement.

The document further states that Tasers are not risk-free but that the devices "have among the lowest risk of injury of any modern force option."

Butler, who needs around-the-clock care since the incident, is seeking lifetime medical costs in the lawsuit. Scruggs estimated that care will cost more than $3.5 million.

"He's just kind of like a 4- or 5-year-old. He just needs to be baby-sat," Scruggs said. "He can't do anything on his own."