9/11 Exposures

Many people were exposed to hazardous conditions during the 9/11 attacks and the cleanup period that followed. These exposures have made many people sick. This page describes some of these hazards at the three disaster sites and provides resources to learn more about 9/11 exposures.

This page is for informational purposes only and is not to be used in determining Program eligibility or certification of a WTC-related health condition.

New York City Area Site

When the planes struck the World Trade Center (WTC) towers, they produced a series of explosions and fires that consumed both buildings. In less than two hours, the Twin Towers collapsed. Their collapse created a massive and dense cloud of toxic dust, gases, and smoke. The dust cloud engulfed highly populated areas of southern Manhattan and Brooklyn (Lioy & Georgopoulos, 2006), and entered offices, schools, and residential buildings. People were exposed both indoors and outside.

Responders and survivors continued to experience exposures in the days and months that followed. Jet fuel contributed to ongoing fires and the six-story pile of smoking rubble at Ground Zero burned off and on for more than three months (Landrigan et al., 2004). WTC dust continued to be stirred and agitated during the many months of cleanup and recovery.

Samples of WTC dust indicated a toxic and complex mixture of particles from building debris and combustion products, such as:

cement,
cellulose,
glass fibers (mineral wool and fiberglass),
soot,
paint (leaded and unleaded),
unburned or partially burned jet fuel,
plastic, and
other materials ignited by fire.

Chemical testing revealed the WTC dust contained hazardous substances, such as:

metals (e.g., lead, cadmium, chromium, magnesium, manganese, aluminum, titanium, and barium),
asbestos,
polycyclic aromatic hydrocarbons (PAHs),
polychlorinated biphenyls,
polychlorinated dibenzodioxins,
polychlorinated dibenzofurans,
pesticides,
phthalate esters,
brominated diphenyl ethers, and
other hydrocarbons (Lioy et al., 2002).

Pentagon Site in Arlington, VA

Similar hazards were found at the Pentagon disaster site, although at far lower levels (Gaborek et al., 2001). Activities inside the affected area of the Pentagon introduced potential exposure to jet fuel, smoke, heat from the fire, and human remains. Samples suggested that hazards were concentrated at the disaster site. See Summary of Evidence on Cleanup of Pentagon and Shanksville Sites [PDF, 70 pages, 1005 KB ] for more information.

Shanksville, PA Site

Unlike the WTC and Pentagon sites, the Shanksville, Pennsylvania disaster site did not involve building debris. Hazards were primarily limited to residual jet fuel and hydraulic fluids, emissions from small-scale fires or smoldering debris from the plane and surrounding groundcover, human remains, and potential hazards created during the response and cleanup (e.g., carbon monoxide, diesel exhaust, and noise). See Summary of Evidence on Cleanup of Pentagon and Shanksville Sites [PDF, 70 pages, 1005 KB ] for more information.

In 2018, the WTC Health Program published an inventory [PDF, 36 pages, 955 KB ] of chemical, physical, biological, and other hazards recognized as 9/11 agents. The document references over 350 hazards that may have been present at the disaster areas and related sites designated in the James Zadroga 9/11 Health and Compensation Act (2010).

References

Gaborek, B. J., Mullikin, J. M., Pitrat, A. T., Cummings, L., & May, L. M. (2001). Pentagon surface wipe

sampling health risk assessment. Toxicol Ind Health, 17(5-10), 254-261.
https://doi.org/10.1191/0748233701th106oa

Landrigan, P. J., Lioy, P. J., Thurston, G., Berkowitz, G., Chen, L. C., Chillrud, S. N., Gavett, S. H.,

Georgopoulos, P. G., Geyh, A. S., Levin, S., Perera, F., Rappaport, S. M., & Small, C. (2004). Health
and environmental consequences of the world trade center disaster. Environ Health Perspect,
112(6), 731-739. https://doi.org/10.1289/ehp.6702

Lioy, P. J., & Georgopoulos, P. (2006). The anatomy of the exposures that occurred around the World

Trade Center site: 9/11 and beyond. Ann N Y Acad Sci, 1076, 54-79.
https://doi.org/10.1196/annals.1371.002

Lioy, P. J., Weisel, C. P., Millette, J. R., Eisenreich, S., Vallero, D., Offenberg, J., Buckley, B., Turpin, B.,

Zhong, M., Cohen, M. D., Prophete, C., Yang, I., Stiles, R., Chee, G., Johnson, W., Porcja, R.,
Alimokhtari, S., Hale, R. C., Weschler, C., & Chen, L. C. (2002). Characterization of the
dust/smoke aerosol that settled east of the World Trade Center (WTC) in lower Manhattan after
the collapse of the WTC 11 September 2001. Environ Health Perspect, 110(7), 703-714.
https://doi.org/10.1289/ehp.02110703