Thousands of people affected by the terrorist attacks of Sept. 11, 2001, are eligible for health care and other assistance, but don't know it.

Legislation introduced this year would require businesses to help spread the word, but it died in committee.

"It's part of an urgent message that recognizes a serious problem ... with regards to a lack of knowledge or awareness people may have to 9/11 compensation," sponsor Assemblyman Nader Sayegh said.

First responders are only a portion of the hundreds of thousands affected, with thousands of others at risk who worked, lived or attended school in the exposure zone in Lower Manhattan.

It's been 21 years, but survivors vividly recall the cloud of ashes and smell of death that blanketed the area for months.

"Even though I remember that the sun was out, it was still very dark," said survivor Indhira Alcantara. "I think back and it's probably, we were all inhaling, you know, other people's ashes."

Alcantara worked in the banking industry at 1 Wall Street across the street from the second tower.

The U.S. Environmental Protection Agency incorrectly said the air was safe to breathe less than a week after the Twin Towers fell.

People who worked near the World Trade Center and exposed to airborne toxins from its collapse have an increased risk of developing dozens of cancers tied to the toxic dust between 9 and 41%, according to the American Association for Cancer Research.

Attorney Michael Barasch, a managing partner at firm Barasch & McGarry, worked adjacent to the towers and represents thousands of workers in the 9/11 community.

"Five days after 9/11, the EPA assured us all the air was safe to breathe ⁠— it wasn't," Barasch said. "But they wanted to reopen Wall Street."

Barasch recounted the results of an autopsy of one of his clients, Detective James Zadroga, who died in 2006.

"Inside his lung tissue, they found round glass, asbestos, chromium, lead benzene," he said. "These are all known carcinogens."

Survivors have access to lifetime health care through the World Trade Center Health Program, but only a fraction of people eligible are participating.

More than 80% of first responders have enrolled, but fewer than 10% of eligible civilians are getting compensated for their Ground Zero exposure, according to U.S. Centers for Disease Control & Prevention.

Sayegh's bill would require businesses operating in the exposure zone from September 2001 through May 2002 to inform employees who worked in the area during that period about their eligibility for the health care and Sept 11 Victim Compensation Fund benefits.

"The concern I have is that if people don't know, then they'll never register," said Sayegh, a Democrat from Yonkers.

Many more survivors could get the medical help they need if the bill gains traction in the Legislature next session and is signed into law. 

The bill would apply to businesses with 50 or more workers.

Notifying former employees will only cost businesses postage, or a phone call.

Sayegh said it's a critical piece of informing as many people possible, as many people left the city after Sept. 11, scattering survivors and their families across the world.

"It's not something costly and is the right thing to do," he added.

Dionne Ortega-Valdez worked on Wall Street on Sept. 11 and is battling breast cancer likely tied to her exposure.

She moved out of the city to Middletown, in Orange County, 15 years ago.

"9/11 is pushed back so far in my head that I never even discussed it, honestly, with my health care professionals in the Hudson Valley, so they didn't even know anything about it," she said.

Ortega-Valdez estimates about 65% of people she worked with at the time of the attacks are suffering from or have died from a related cancer or respiratory disease.

Alcantara, who lives in Poughkeepsie, said revisiting the trauma of 9-11 is difficult, but said it must be done for survivors to understand their medical risks and potentially save their lives.

"It's not something that goes away," she said.

But survivors, advocates and lawmakers agree: Working together is the only way to make headway for the 9/11 community.​

"We have a moral obligation to look out for each other," Barasch said.

Lawmakers are working on the Assembly and Senate Health committees to hold a public hearing about the issues facing the estimated 500,000 survivors.

EDITOR'S NOTE: This story has been edited to correct the spelling of James Zadroga's name.