Recently, virtual world technology has been successfully used to create interesting and useful applications in the context of scientific research, ranging from visualization of static 3D representations of molecular entities to full execution of astrophysical simulations. Unfortunately, the majority of these applications are somewhat limited by the current functionality of the virtual world client software, constraining them to provide only the most basic features of user interfaces. Thus, the implementation of applications such as training programs becomes quite challenging due to the high level of interaction a user must have with the training environment itself. In order to analyze the level of usability for virtual world based applications, we will introduce Open Bio Safety Lab, our implementation of a virtual world based training application in bio-risk management, which is one of the most important areas for training systems nowadays. We also present the results of our exploratory test study with twenty-four subjects, which indicates a high degree of usability of our system, not only for the testing aspect of the training, but also for the learning aspect. © 2011 IEEE.