Researching Health Risks for the Dogs of 9/11

Author: Sharon M. Albright, DVM, CCRT

The unique bond we share with dogs was unmistakable following the terrorist attacks of September 11, 2001. From the search and rescue dogs that worked to sort through the rubble, to the therapy dogs that buoyed the spirits of first responders and communities, these special canines were critical to recovery efforts. It is estimated that approximately 300 search and rescue (SAR) dog teams were deployed to three disaster sites following 9/11. Shortly thereafter, the AKC Canine Health Foundation (CHF) collaborated with researchers at what is now the Penn Vet Working Dog Center to monitor the behavioral and physical health of these SAR dogs. Since then, CHF and its donors have invested more than $550,000 to collect and analyze this data.

SAR dogs deployed following 9/11 were exposed to smoke, ash, dust, and chemicals through inhalation, absorption through the skin and eyes, and oral ingestion (either directly or indirectly by licking their fur or feet). One year after the disaster, deployed dogs had higher blood levels of globulins (proteins of the immune system), bilirubin (an indication of liver disease), and alkaline phosphatase (ALP – a liver enzyme) compared to SAR dogs not deployed to 9/11 sites.1 Five years after the disaster, these levels had returned to normal in deployed dogs and the incidence of cancer and age at death were similar in deployed and non-deployed dogs.2

The last known dog deployed to a 9/11 site died in June of 2016. (Read “In Memory of the September 11 Search & Rescue Dogs.”) Investigators continue to analyze fifteen years’ worth of data to answer concerns about the risks these dedicated SAR dogs faced. The latest publication associated with the 9/11 Canine Medical Surveillance Study examines the cause of death of 95 SAR dogs deployed to 9/11 sites (exposed dogs) compared to 55 SAR dogs not deployed to these specific locations (non-exposed dogs).3 Survival time was similar between both groups. The most common cause of death in each group was degenerative disease such as osteoarthritis or impaired mobil­ity, kidney failure, heart disease, or degenerative myelopathy. Cancer was the second most common cause of death in each group. Even when examined in relation to dog breed, organ system affected, age at deployment, duration of deployment, sex, or blood results one year after deployment, there was no significant difference in cause of death between the two groups.

Sixty-three dogs (44 exposed and 19 unexposed) had a necropsy (animal autopsy) performed following their death. Particulate matter was found in the lungs of 95% of exposed dogs examined, but only 63% of unexposed dogs. Anthracosis, a condition where brown/black pigmented material is found within airway macrophages (a type of white blood cell), was present in similar amounts in the lung tissue of 61 of the 63 dogs. Therefore, anthracosis appears to be an occupational hazard for all SAR dogs but was not associated with an increased risk of cancer or other lung disease in this population.

Based on these results, the long-term risk of adverse health effects in SAR dogs deployed following 9/11 was low. Degenerative conditions associated with old age were the most common cause of death. Principal investigator and Director of the Penn Vet Working Dog Center, Dr. Cynthia Otto says, “To me one of the most encouraging things about our study is that Search and Rescue dogs live long and healthy lives. I like to think that the long lives of these dogs may be a result of their physical fitness, their strong bond with their handlers and their sense of purpose. Although it is only speculation and perhaps a bit anthropomorphic, if we could enhance the physical fitness, bond and sense of purpose for all of our dogs, everybody wins.”

Search and rescue dogs continue to play a critical role in the prevention of and recovery from natural and man-made disasters. This research provides important information on the short and long-term health risks for these canines. CHF and its donors acknowledge the training and dedication of all SAR teams. Collaborating with working dog handlers, veterinarians, and researchers, we will continue to improve the health of working dogs and all dogs. Learn more about our work at



  1. Otto CM, Downend AB, Serpell JA, et al. Medical and behav­ioral surveillance of dogs deployed to the World Trade Cen­ter and the Pentagon from October 2001 to June 2002. J Am Vet Med Assoc 2004(225), 861–867.
  2. Otto CM, Downend A, Moore G, et al. Medical surveillance of search dogs deployed to the World Trade Center and Pentagon: 2001–2006. J Environ Health 2010(73), 12–21.
  3. Otto, C. M., Hare, E., Buchweitz, J. P., Kelsey, K. M., & Fitzgerald, S. D. (2020). Fifteen-year surveillance of pathological findings associated with death or euthanasia in search-and-rescue dogs deployed to the September 11, 2001, terrorist attack sites. Journal of the American Veterinary Medical Association, 257(7), 734–743. 

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