Senate Republicans last week blocked action on a bill appropriating up to $3.2 billion for medical programs caring for people who fell ill after breathing in ash and pulverized building materials at ground zero.
The act would have guaranteed at least eight years of strong, even lavish, funding for existing health programs for 9/11 responders and other New York City residents exposed to the dust.
Thousands of people who have lingering respiratory problems, post-traumatic stress disorder and other ailments have been getting checkups, counseling, medication and other treatments at federally funded centers around New York City and its suburbs.
The centers, though, have perpetually seemed to be living on borrowed time. No law mandates that the programs must continue.
Congress has chosen to fund them one fiscal year at a time, meaning there is no guarantee the money will be there a year from now.
"We don't know what the future holds," said Jeffrey Hon, World Trade Center health coordinator for the New York City Health Department.
Hon said there is no immediate danger that the services will end, but because there is no sustained budget, it is difficult to keep researchers and staff in the program or hire top medical talent.
Patients getting care never know for sure whether they will be able to turn to the same clinics for help a year down the road.
Since 2002, Congress has given the health clinics $475 million, including a $70 million appropriation for this fiscal year. A large chunk of the money remains unspent, meaning the centers could keep operating for some time even if appropriations were completely cut off.
The programs, which offer medical care free of charge, are especially valuable to ground zero cleanup workers who don't have private health insurance or whose health plans don't cover the full cost of their care.
"If these programs are no longer here, it would be a disaster," said Alex Sanchez, who developed chronic asthma, lung nodules, an upper airway obstruction and a nasty cough after working as a cleaner who swept mountains of dust from skyscrapers near ground zero.
Sanchez said that in the years it took his worker's compensation claim to be approved, the program was the only way he could afford to pay for his 14 medications.
Other workers are in a similar position now because they have lost their jobs - and their health insurance - in the recession, he said.
In addition to the health care money, the legislation would set aide $4.2 billion to compensate people who lost their jobs or suffered other economic problems because of illnesses caused by the terror attacks.
That portion of the bill would be similar in many respects to a legal settlement, also partly funded by American taxpayers, that could provide more than $800 million for people who have illnesses that might be linked to the attacks.
Nearly 10,000 people have joined the settlement so far, but thousands more believed to have been exposed to the trade center dust have either decided not to sue or filed their legal complaints too late to be included in the deal.
"There are a decent amount of people out there with real injuries who were not a part of the litigation," said Matthew McCauley, a lawyer with the firm Parker Waichman Alonso, which is among the few that have been willing to take on new claims.
He and other lawyers said most of the workers face "enormous hurdles" if they wish to try to get compensation through the courts now outside of the settlement, especially those with illnesses that might be difficult to prove are connected to trade center work.
Scientists have said that thousands of people exposed to trade center dust have developed respiratory problems similar to asthma, with a smaller number suffering more serious ailments. Many have symptoms of post-traumatic stress disorder.
Doctors still don't know, however, whether there is any connection between the dust and potentially fatal illnesses like cancer.
Cancer is killing a growing number of people who were involved in the 9/11 cleanup, but researchers say the death rate so far has been similar to that of the general public.
That lack of a solid link has given some critics of the federal bill pause at allocating so many billions of dollars for treatment.
That concern doesn't carry water with people like Richard Dambakly, a former phone company worker exposed to the dust while repairing damage in lower Manhattan. He was diagnosed in early 2002 with lymphoma, an immune system cancer.
"Everyone told me the same thing. They said, you can't get sick with cancer in just two or three months," said Dambakly, who now lives in Hampstead, N.C.
"I know as a fact - a fact - that I got sick from ground zero ... I was there for four months straight, 12 to 16 hours a day. Not one day off. I was coughing so bad, I thought my chest was going to blow right out of my body.
"You're going to sit back and tell me I didn't get sick from ground zero? Take a walk," he said.
Supporters of the bill say they are trying to find a way to pass it by the end of the year.