A California man, who had a heart attack after being hit by a Taser stun gun and is now disabled, filed a personal injury lawsuit against the weapon maker.

The lawsuit alleges that Taser International, manufacturers of the controversial “non-lethal” police weapon, had past knowledge that voltage from the Taser could cause permanent harm to a person, specifically when the weapon is fired directly at a person’s chest as in the case of Steven Butler.

Butler, a resident of Watsonville, Calif., admitted to CNN that he was drunk and acting out on the night of October 7, 2006. Butler was on a city bus and refused to step out of the vehicle, even after area police officers ordered him to do so. According to CNN, the police officer then used a Taser three times on Butler.

Doctors later reported that while Butler was shocked, he went into cardiac arrest. Emergency medical technicians nearby were able to bring him back to life, but he was still left with permanent impairments such as loss of short and long term memory. Butler’s attorneys have claimed that while he was in cardiac arrest, Butler was deprived of oxygen for at least 18 minutes as a result of the Taser injury.

John Burton, who is representing Butler and his family in the injury lawsuit, told CNN he can prove that tasers can cause heart attacks if fired near a person’s chest, and that Taser International knew about this before October 2006.

“We suspect they had all the necessary data since 2005, since they were funding the study,” Burton told CNN about whether Taser International knew if their weapons could cause harm.

In early 2006, the American College of Cardiology Foundation published a study that was funded by Taser International to see what effects the weapons had on hearts. The testing was performed on pigs, according to CNN.

Within the published piece, authors said it wasn’t likely that Tasers could cause a heart attack, but they did recommend that the darts should not be fired near the heart to avoid the possibility altogether.

The shock coming from darts connected to wires that lead from the handheld Taser mechanism can drastically spike a person’s heart rate, CNN reported. An average resting heart rate is between 60 and 80 beats per minute but a Taser shock can spike a heart rate to as high as 220 beats per minute.

Dr. Douglas Zipes, an Indianapolis-based cardiologist, is scheduled to testify against Taser International.

“I think Taser has been disingenuous and certainly up to 2006 — the case we are talking about — Taser said in their educational materials that there was no cardiac risk whatsoever, that Taser could not produce a heart problem, that there was no long lasting effect from Taser,” Zipes told CNN.