A letter from the police department, obtained by CNN, confirmed that he was "permanently disabled" and could be fired. Bean and his union rep said Newtown could only afford to pay two years of long-term disability. He has a dozen years left on the job before being able to retire.

The union that represents Newtown police officers may file a lawsuit.

"The men and women of the Newtown Police Department who did respond that day did their job," said Scott Ruszczyk, the union president. "They lived up to their end of their contract. It's now time for the town to live up to their end."

5 things to know about PTSD

Joe Aresimowicz, the House majority leader in the state General Assembly, said Connecticut covers mental health care for long-term disability claims only if the diagnosis is accompanied by physical injuries.

"We don't just cover mental injuries," he said. "The last thing you want is a first responder getting ready to enter a situation and have them think, 'I wonder what long-term harm this will do me?'"

In an e-mail, Newtown Police Chief Michael Kehoe declined to discuss the matter. Local officials did not return calls or e-mails seeking comment.

Bean told CNN that he broke down in tears after Sandy Hook Elementary School was cleared. He drank and smoked excessively. He even contemplated cutting himself with a razor. "I didn't want to kill myself but I wanted to feel something," he said. "Had no feeling, no sensation, no nothing."

Adam Lanza, 20, shot and killed 20 young children and six teachers in the school before taking his own life -- a massacre that prompted a national debate over tougher gun laws.

Bean said he knew he was in "deep, deep trouble" after entering a store one day.

"I looked at everyone in that store like they was going to kill me," he said. "I could not get out of that store fast enough. I looked around, and there was a crowd of people, and all I saw were flashbacks -- (the) firehouse with the families or what I saw that day."

Bean, 38, who's married with two children, remains in therapy. He said he is grateful for support from one group in particular, called Save a Warrior. Bean urges others suffering from PTSD to seek help.

"The Save A Warrior program that I went through is free," he said. "We even had some law enforcement from LAPD and NYPD go through the program."

Other Newtown police officers were diagnosed with PSTD, but Bean was the only one unable to return to work, union officials said.

"If I had my arm chopped off, they'd would say, 'Oh yeah, he's hurt.' But instead they're like, 'We can sweep (this) under the rug and not necessarily have to pay because ... it's not physically seen.' That's the problem with PTSD ... people don't see it," said Bean, his voice trailing off.