Since Operation Desert Shield/Desert Storm, Gulf War veterans have expressed concerns about health effects that could be associated with their deployment and service during the war. Although similar concerns were raised after other military operations, the Gulf War deployment focused national attention on the potential, but uncertain, relationship between the presence of chemical and biological (CB) agents and other harmful agents in theater and health symptoms reported by military personnel. Strategies to Protect the Health of Deployed U.S. Forces which is one of the four two-year studies, examines the detection and tracking of exposures of deployed personnel to multiple harmful agents.