Veterans who participated in a series of tests during the 1960s known as Project SHAD (Shipboard Hazard and Defense) show no significant increase in adverse health outcomes, specific causes of death, or death rates compared with a similar group of veterans who were not involved in the tests, says a new report from a committee of the National Academies of Sciences, Engineering, and Medicine. The congressionally mandated report builds on a 2007 Institute of Medicine report, which also found no consistent, specific patterns of poorer health among SHAD veterans.
In addition, although the 2007 report suggested an increased risk of death from heart disease for SHAD veterans, the committee that wrote the new report found no such increased risk after analyzing cause-of-death data from seven additional years of follow-up.
Project SHAD was a series of tests conducted by the U.S. Department of Defense during the 1960s to evaluate the vulnerabilities of U.S. Navy ships to chemical and biological warfare agents. Many of the substances used in the tests were simulants and tracers presumed to be innocuous such as Bacillus globigii and sodium fluorescein, but some tests involved active agents such as infectious bacteria Coxiella burnetii, which causes Q fever, and the nerve agents sarin and VX. Approximately 5,900 veterans, primarily from the Navy and Marine Corps, were involved in the testing, which were classified as "secret" or "top secret."
In 2010, Congress asked the Academies for an additional study on the potential long-term health effects for SHAD veterans. The committee that conducted the new study evaluated causes of death of veterans in the study population since the 1960s and the diagnoses assigned at hospital and outpatient visits in data from the VA health system and from Medicare from 1999 through 2011. In addition, it examined data for various subgroups of the SHAD veterans studied - for example, enlisted personnel vs. officers, and groups who may have received multiple exposures to one or more of certain substances. The committee also reviewed the scientific literature published since 2000 on the agents, simulants, tracers, and decontaminants used in the tests, from which it generated hypotheses on potential health effects that might be associated with exposure to six of the substances. These hypotheses were used to target portions of the analyses. Exploratory analyses were also performed to ensure that unanticipated associations between SHAD testing and health outcomes in veterans would not be overlooked. Multiple analyses found no evidence of worse health outcomes among SHAD veterans.
The committee acknowledged that its study - like all epidemiological studies - has limitations. Project SHAD occurred more than 50 years ago, making it difficult to account for all of the factors that may have influenced veterans' health. Although a request for classified information on the concentrations of test substances at sampling stations was denied, the committee said it did not expect that the classified information would have altered its findings.