DENVER (AP) -- Police unions across the U.S. are pushing for officers to be able to collect workers' compensation benefits if they suffer post-traumatic stress disorder, whether they got it from the general stress of police work or from responding to a deadly shooting rampage.

"I can't imagine a department in the United States without officers who have symptoms of PTSD and are still working," said Ron Clark, chairman of the Badge of Life, a group of active and retired officers working to raise awareness of police stress and suicide prevention.

"We're beginning to see more and more states talking about this," he said.

But some police chiefs and municipal leaders oppose lawmakers' efforts, even in states such as Connecticut and Colorado, the scenes of some of the deadliest massacres in recent years. They say they are concerned the benefits would strain budgets and lead to frivolous claims.

"We support and appreciate the efforts of our police and firefighters, but there's a concern when you expand benefits," said Betsy Gara, executive director of the Connecticut Council of Small Towns.

Legislation has been emotional in that state, still haunted by the December 2012 mass shooting at Sandy Hook Elementary School in Newtown.

Newtown police officer Thomas Bean told lawmakers his depression, anxiety and suicidal thoughts left him unable to work. "I'm always being re-traumatized because I don't know what my future is," Bean testified in March.

Connecticut allows police and firefighters to collect workers' compensation if they use deadly force or witness a colleague's death. New legislation would expand it to all municipal employees diagnosed with PTSD after witnessing a violent event or its aftermaths.

Federal employees and military members can collect compensation if a psychiatrist finds PTSD symptoms. But most states require officers and firefighters to have an accompanying physical injury.

Supporters say lawmakers' efforts to change that are encouraging, but the push-back shows a stigma remains.

"They don't get too worked up when an officer gets shot or physically assaulted because they can see it," Clark said. "If you think every cop is just going to run to that lifeboat and say, `I have PTSD,' I just don't see it."

It is hard to say how many officers suffer symptoms because many do not come forward for fear of seeming weak, Clark said.