The compensation fund for victims of 9/11 is running out of money and will cut future payments by 50 to 70 percent, officials announced Friday.

"It means that everything we were told and promised is now going to be cut in half. To be told one thing and now you're getting something significantly less. So we're going to have to learn how to deal with that," said Bridget Gormley, whose father, William, died of 9/11-related cancer.

September 11th Victim Compensation Fund special master Rupa Bhattacharyya said she was "painfully aware of the inequity of the situation" but stressed that awarding some funds for every valid claim would be preferable to sending some legitimate claimants away empty-handed. "I could not abide a plan that would at the end of the day leave some claimants uncompensated," Bhattacharyya said.

Nearly 40,000 people have applied to the federal fund for people with illnesses potentially related to being at the World Trade Center site, the Pentagon or Shanksville, Pennsylvania, after the 2001 terror attacks there, and about 19,000 of those claims are pending. Nearly $5 billion in benefits have been awarded out of the $7.3 billion fund.

Bhattacharyya said fund officials estimate it would take another $5 billion to pay pending claims and the claims that officials anticipate will be submitted before the fund's December 2020 deadline.

Absent that funding, officials determined that pending claims submitted by February 1 would be paid at 50 percent of their prior value. Valid claims received after that date will be paid at just 30 percent.

Members of Congress responded to Friday's announcement by vowing to reauthorize the compensation fund.

"This is devastating news to the thousands of sick and injured 9/11 responders and survivors who were promised, and have been counting on, being fully compensated for the losses they have suffered," Democratic Reps. Jerry Nadler and Carolyn Maloney and Republican Peter King said in a statement.

They said they would introduce legislation to make the compensation fund permanent and to compensate all legitimate claimants. "Our bill would restore any cuts to awards, ensure that future eligible recipients are fully compensated, and make the VCF program permanent," the lawmakers said.

The Senate's top Democrat, Sen. Charles Schumer, said the fund is supposed to provide "peace of mind to those sickened after the horrific attack."

"For too many, ailments and disease from exposure to that toxic airborne brew have taken years to show up and - as the need for the fund grows - the chance it may not have adequate resources to take care of our heroes is just unacceptable," Schumer said in a statement.

The collapse of the trade center in 2001 sent a cloud of thick dust billowing over Lower Manhattan. Fires burned for weeks. Thousands of construction workers, police officers, firefighters, and others spent time working in the soot, often without proper respiratory protection.

In the 17 years since, many have seen their health decline, some with respiratory or digestive-system ailments that appeared almost immediately, others with illnesses that developed as they aged, including cancer.

Bhattacharyya said the volume of claims has increased over the past year, with more than 8,000 claims filed in the last four months.

Reasons for the increase include the long latency period for some cancers as well as an increase in applications by people who lived or worked near the trade center but were not actively involved in recovery efforts, Bhattacharyya said.

Gormley's father spent months working at the World Trade Center site with his company, Engine 310/Ladder 174 in Brooklyn. He was diagnosed with 9/11-related bladder and lung cancer in 2016. He died two years later at age 53.

(Firefighter William Gormley, who wasn't diagnosed with 9/11-related bladder and lung cancer until 15 years after the terrorist attack. He died two years later).

"More and more people are getting sick, and they're getting sick because of the illnesses. There's latency periods, so they pop up years later. There are cancers we don't even know about yet that are going to come down, 10 years on the line, and we're not going to have money to deal with those people because you say the timeframe doesn't fit," Bridget Gormley said.

Michael Barasch is an attorney representing hundreds of first responders and survivors sickened after the September 11th terror attack.

"Today's announcement by the special master is a real gut punch to the entire 9/11 community," Barasch said. "There just isn't enough money. So Congress must do the right thing now and extend this fund and give more funding."

Until Congress allocates more money to the fund, the families of those who have died will continue to put pressure on lawmakers in Washington.

"Everyone was here in the same capacity during the same time period, and I don't think that someone should get, you know, a smaller compensation," said Robert Tilearcio, whose father died of 9/11-related cancer. "opposed to people that had applied earlier or received cancers earlier. Because you never know when you're going to get cancer."

9/11 victims and their families will be in Washington in a span of two weeks to ask lawmakers on Capitol Hill to add more money to the victims' compensation fund.

Information from the Associated Press was used in this story.