New York City police and firefighters, joined by comedian Jon Stewart, rallied on Capitol Hill Wednesday as part of a bipartisan plea for Congress to renew funding for 9/11 first responders' health care. 

The funding, part of the James Zadroga 9/11 Health and Compensation Act, is set to expire in a matter of weeks. A group of city FDNY and NYPD vets descended on D.C. to appeal to lawmakers to permanently extend it. 

Without an extension, more than 33,000 surviving firefighters, police officers, and paramedics now too sick to work would lose access to important federal health benefits and other money. 

"Do you remember when the government told us that the air was safe to breathe?" Richard Alles, deputy chief of the Uniformed Fire Officers Association, asked the crowd, which muttered "yes" in unison. "I do too, and now it's time for Congress to get off its butt and do its job." 

Stewart, recently retired from "The Daily Show," made the trip, too, and warned first responders flanking him in the shadow of the U.S. Capitol dome about how difficult things can be inside. 

"Today on the Hill, you will be exposed to possibly toxic levels of bull--- and arrogance," Stewart said, to laughter. "You're strong men and women but these are conditions you may have never faced before." 

Half a decade ago, some lawmakers opposed this bill, in part because of the uncertain costs of covering an unknown number of victims suffering from ailments they couldn't always directly tie to Ground Zero. 

But that's all changed now, according to Sen. Kirsten Gillibrand, D-N.Y., who explained that since the initial fight in 2010, doctors and lawmakers alike "have the benefit of studies and epidemiology that links the exact cancers to the exact toxins that were released ... and we didn't have this information five years ago." 

Gillibrand and others from the New York delegation are leading the effort to permanently extend the federal funding, but the WTC Health Program touches nearly every corner of the United States. 

There are 435 congressional districts; 429 of them have a resident enrolled in the program.

Peter Doocy is currently a Washington D.C.-based correspondent for FOX News Channel (FNC).  He joined the network in 2009 as a general assignment reporter based in the New York bureau.