National Institute for Occupational Safety and Health director John Howard is scheduled to make a determination by Saturday, though his decision might not be announced until Monday.
Adding cancer to the list of covered conditions would make hundreds, or even thousands, of residents and rescue and recovery workers eligible for government-financed medical treatments and sizable payments for lost wages and diminished quality of life.
But it might also put a severe financial strain on the program.
If Howard accepts the panel's recommendations in their entirety, there would likely be a surge of costly claims in a system now primarily helping people with conditions that aren't life-threatening, like asthma, chronic sinus irritation, sleep apnea or acid reflux disease.
The total number of people exposed to the dust is unknown, but 60,000 people have already enrolled in 9/11 health programs for people who lived or worked within the disaster zone, which covers most of Manhattan south of Canal Street.
Congress capped funding for the program at $1.55 billion for treatment, and $2.78 billion for compensation payments.
The special master overseeing applications for compensation, Sheila Birnbaum, said that unless Congress increases those amounts, she may have to prorate payments based on the number of people who apply and the severity of their illness.
"The addition of cancers, of course, complicates the issue," she said. Compensation awards for people with cancer - especially fatal cases - are likely to be significantly larger than claims being submitted now for other illnesses, she said. Any prorating based on a funding shortage would mean less money for people with other types of health problems.
That prospect has alarmed some advocates for the workers like Noah Kushlefsky, an attorney with the firm Kreindler & Kreindler, who represents about 3,800 people who intend to file claims.
"The budget should have no bearing on whether these people get help," he said. "Either we believe that illnesses were caused by the toxins that were down there - in which case, people should be cared for - or we don't."