More than 30,000 people enrolled in the World Trade Center Health Program have been diagnosed with at least one type of cancer linked to the September 11 attacks. That number has climbed steadily each year and continues to grow more than two decades later, as cancers with long latency periods are still emerging in people who were exposed to toxic dust and smoke in Lower Manhattan.
How the Numbers Have Grown
The cancer toll from 9/11 has increased dramatically over time. By 2018, roughly 10,000 first responders and others who were in the World Trade Center area had been diagnosed with cancer. That figure has since tripled as more people develop cancers years or even decades after their initial exposure, and as awareness of the WTC Health Program has brought more patients into the system. The rate of some cancers among first responders runs up to 30 percent higher than in the general population.
These numbers only reflect people enrolled in the federal health program. The true count of 9/11-related cancers is almost certainly higher, since not everyone exposed has enrolled, and some may have developed cancer without ever connecting it to their time near Ground Zero.
What People Were Exposed To
When the Twin Towers collapsed, they created enormous dust clouds that blanketed hundreds of densely populated city blocks with a toxic mixture of asbestos, silica, heavy metals, concrete particles, and pulverized glass. The debris pile burned for months, with fires lasting through the end of December 2001 and flare-ups continuing into 2002. Those fires released carcinogenic combustion byproducts into the air over a prolonged period.
This wasn’t a single moment of exposure for most people. First responders spent weeks or months working at the site, often without adequate respiratory protection in the early days. Residents, office workers, students, and others in Lower Manhattan breathed contaminated air and lived or worked in buildings coated with toxic dust. The exposure zone recognized by the federal government covers all of Manhattan south of Houston Street and parts of Brooklyn within a 1.5-mile radius of the former World Trade Center site.
Why Cancers Are Still Appearing
Different cancers take different amounts of time to develop after toxic exposure, which is why the number of 9/11-related cancer diagnoses keeps rising. The WTC Health Program has established minimum latency periods for the cancers it covers. Blood cancers like leukemia and lymphoma can appear in as little as 146 days after exposure. Thyroid cancer requires a minimum of 2.5 years. Most solid cancers, including lung, prostate, and colon cancer, have a minimum latency of 4 years. Mesothelioma, a cancer strongly linked to asbestos, has an 11-year minimum latency and often takes 20 to 50 years to develop.
This means the wave of 9/11-related cancers is not over. Mesothelioma cases in particular are expected to continue appearing for decades. And because many of the people exposed were relatively young at the time, they have long lifespans ahead in which delayed cancers could emerge.
Who Is Affected
The affected population is broader than most people realize. Firefighters, police officers, and other emergency workers make up a large share of 9/11 cancer patients, but the WTC Health Program also covers construction and cleanup workers who spent time at Ground Zero, residents and workers in Lower Manhattan, students who attended schools near the site, and even people who were passing through the area on September 11.
Children who were in the disaster zone are a particular concern. Researchers still do not have a clear picture of cancer rates among people who were young children or infants in Lower Manhattan at the time of the attacks. Because children’s developing bodies are more vulnerable to environmental toxins, experts have raised the possibility that unusual cancers, particularly lung cancers and mesothelioma from asbestos exposure, could appear in this group in coming years.
The Death Toll From 9/11 Illnesses
Cancer is now one of the leading causes of death among people sickened by 9/11 exposure. By 2018, more than 2,000 deaths had been attributed to 9/11-related illnesses, including cancers and respiratory diseases. Mount Sinai researchers noted at that time that deaths from 9/11 diseases were on pace to outnumber the 2,977 people killed on the day of the attacks itself. That threshold has since been crossed.
The federal government has responded by making the WTC Health Program permanent. Legislation signed into law provides lifetime funding for the program, ensuring that first responders and survivors will continue to receive medical monitoring and treatment for covered conditions, including more than 60 types of cancer, without worrying about the program expiring.
Types of Cancer Linked to 9/11
The WTC Health Program covers a wide range of cancers connected to the exposures at Ground Zero. The most commonly diagnosed include cancers of the lung, prostate, skin, thyroid, bladder, kidney, and colon, as well as blood cancers like non-Hodgkin lymphoma and leukemia. Mesothelioma, though rarer, is one of the most directly tied to the asbestos released during the tower collapses.
Many patients have been diagnosed with more than one cancer. The combination of multiple carcinogens in the WTC dust, the intensity and duration of exposure, and the years that have passed since the attacks all contribute to the high and still-growing cancer burden in this population.