I haven’t worked since the 11th. After that day, I went down digging for five or six days in a row. I was possessed. I felt guilty being home. I had to be there. But we didn’t find one survivor. Not one. After six days of digging, I couldn’t talk. I’d lost my voice because I wasn’t wearing a mask. My lungs were shot. I couldn’t see right. And I wasn’t one of the worst ones.

That was Engine 47 firefighter Louie Cacchioli, then a two-decade FDNY veteran, as recounted in the book The American Spirit: Meeting the Challenges of September 11. Here’s more:

Louie Cacchioli’s story is not unique. He’s a survivor, of course, but 343 of his firefighting brothers were not. And yet on this week’s commemoration of the 9/11 attacks, we learned of a sad milestone: More firefighters have now died from 9/11-related illnesses than died in the attacks that day.

Let that sink in.

And Louie was right. His exposure was awful, horrible, but he wasn’t “one of the worst ones.” In a New York Times piece titled “The Fire Department’s Painful 9/11 Legacy,” James Barron reports, “The Fire Department also says that at least 11,000 of its members have illnesses related to their work on Sept. 11. At least 3,500 have cancer.”

Three years ago, on the 20th anniversary of that murderous attack, Scientific American did a deep dive into the health conditions of responders and survivors more broadly.

Nearly 3,000 people died during the deadliest terrorist attack in world history. But in the two decades since then, the number of deaths among survivors and responders — who spent months inhaling the noxious dust, chemicals, fumes and fibers from the debris — has continued creeping up. Researchers have identified more than 60 types of cancer and about two dozen other conditions that are linked to Ground Zero exposures. As of today [i.e., 3 years ago], at least 4,627 responders and survivors enrolled in the World Trade Center Health Program have died.

The Centers for Disease Control is also tracking and treating the survivors of 9/11 via the World Trade Center Health Program, a federal program providing “high-quality, compassionate medical monitoring and treatment for WTC-related conditions to those directly affected by the September 11th attacks in New York, at the Pentagon, and in Shanksville, Pennsylvania.” On Wednesday, the program’s administrator, Dr. John Howard, noted this:

We currently serve over 128,000 members, with over 81,000 members diagnosed with one or more certified WTC-related physical and mental health conditions. However, our work does not end here. Over 400,000 individuals are estimated to have been exposed to toxins or other hazards on 9/11. We remain dedicated to supporting our existing members, and we are eager to reach more survivors and responders deserving of care.

When we think of 9/11, we rightly think first of the 2,977 who died that day. But as Howard noted, the numbers beyond that primary group are staggering. And for many, the struggle for recognition, health benefits, and compensation continues — not only from the WTC Health Program but also from the September 11th Victim Compensation Fund. As The New York Times reports, “At issue was the program’s cancer latency policy, which stipulates that many cancers diagnosed before Sept. 11, 2005, cannot be considered linked to the attacks, and therefore those victims and their families are not eligible for federal benefits.”

Regarding that latency period, blood-related cancers such as leukemia and lymphoma can materialize within a year of exposure. So what becomes of someone like David Skiba? A 37-year-old state trooper at the time of the attacks, Skiba spent long hours and days “immersed in thick clouds of toxic dust” as he helped supervise the rescue and recovery efforts at Ground Zero.

As Skiba’s 26-year-old son Matt says, “The fact that his cancer got diagnosed eight months early has repeatedly slapped us in the face. If you were down there helping people, you should get recognition no matter what, in my opinion.”

It’s not just cancer, though, and not just afflictions of the blood, the lungs, and the viscera. As The Washington Post adds, “Only recently … have scientists begun to find that cognitive impairment and dementia are also afflicting first responders at rates far higher than in the general population.”

On the one-year anniversary of the attacks, then-President George W. Bush wrote, “Debris from what was once the World Trade Center has been cleared away in a hundred thousand truckloads,” and that “life seems almost normal.”

By then, life may well have seemed “almost normal” to the vast majority of us — those of us who weren’t there that day, either in Lower Manhattan or at the Pentagon or in that field in Shanksville. But for many thousands of 9/11 victims and their families, life will never be normal again. For their sake, we should never forget.

Never Forget.