There is abundant doctrine requiring planners and operators to consider environmental protection in deployment operations. Joint Publication (JP) 3-34, Joint Engineer Operations, for instance, outlines environmental considerations for both domestic and foreign training and operations.1 Many commands have also included an annex L in operation plans, which describes the overall environmental mission. However, these plans seldom include specific instruction or goals on the tactical level. In fact, although many lessons from the Balkans and other contingency operations have been documented and studied, lessons are now being relearned in the Iraq and Afghanistan operations.2 In addition, despite requirements to conduct environmental health site assessments prior to establishing base camps, they were not always completed during Operations Iraqi Freedom and Enduring Freedom because commanders did not advise preventive medicine personnel where camps were being set up.3 This may be, at least in part, attributed to field commanders not being aware of the function of their preventive medicine assets.4 It should be noted that Final Governing Standards (FGS), or the Overseas Environmental Baseline Guidance Document (OEBGD) where FGS are not available, currently do not apply to contingency military operations. However, policy is being drafted to extend the FGS or OEBGD to contingency bases. There is a difference between an environmental baseline study and an environmental health site assessment, though they are inextricably related. While an environmental baseline study evaluates the status of the environment, an environmental health site assessment evaluates the impact of the environment on the warfighter. In this article, we discuss both studies as they are key to successful military operations.