Despite that rejection, the city of Stamford eventually agreed to cover the officer's medical bills, but it required him to change doctors.
Chiafari, 53, accompanied by his union president and about a dozen fellow officers, urged lawmakers to pass a bill that would allow claims for mental or emotional impairment under workers' compensation laws when officers use deadly force on animals that attempt to harm them.
Chiafari said he's not looking for sympathy. Rather, he said he doesn't want another officer to go through what he experienced after confronting a raging animal and "a scene of carnage."
"It was unlike anything I'd felt before. It was a feeling of like cloaked in darkness, gloom, like there was this sense of hopelessness. It was a depression beyond depression, you can't even really put it into words," he said. "And it would be worse in the morning. I'd wake up and I'd feel this terrible feeling, this sense of doom. The worst part of it is, you feel trapped like 'I'm not coming out of this."'
The chimpanzee named Travis went berserk after its owner asked her friend, Charla Nash, to help lure the pet back into her house. The animal had ripped off Nash's hands, nose, lips and eyelids.
Nash has been hospitalized at the Cleveland Clinic for the entire year since the attack.
Chiafari said he was shocked when he saw how badly Nash had been hurt and the enraged animal still attacking her. He and another officer, who could not determine if Nash was a man or woman, parked their patrol cars on either side of her to shield her from the chimp.
After retreating for a few seconds, the animal then turned on Chiafari, rocking his car like a toy, knocking the mirror off like it was butter and managing to open the driver's side door and climb inside.
"The thing touched me. It came in my car and I felt him brush against me," Chiafari said. "With the snarls, he was saying, 'You're next.' Thankfully I got the gun out of the holster and shot."
Chiafari said he returned to work after three weeks, but received counseling for about two months, until the city required him to switch doctors. He has since received some additional counseling, but not regularly.
Sgt. Joseph Kennedy, president of the Stamford Police Association, said the legislation would not affect routine duties, such as putting down a wounded deer or a rabid raccoon. Rather, he said it's to help officers like Chiafari who confront physical deadly force.
"This is to deal with serious, serious, serious physical injury," Kennedy told lawmakers.
Chiafari told the lawmakers he had nightmares and that, while walking in a mall, he had visions of women without faces. He said vivid memories still flash back occasionally.
"It was a terrible thing. It has changed my life. I have been on other scenes before in my 25 years, I've seen it all. I've seen horrible things. I came to work, I dealt with it," he said. "But this particular call was so bad that it really affected me.
"I didn't even know what post-traumatic stress was before this. I used to hear about it, I didn't know if I believed in it. Well, I found out, it is definitely a real thing."