The risks firefighters face are constantly changing on both the fireground and in the training scenarios. Live-fire training is evolving rapidly in part due to the use of new materials to provide smoke and fire development that appears more closely aligned with today's fireground. However, the occupational health impacts of burning these fuels is unknown and claims that one fuel is more or less safe than another are rarely supported by data. Furthermore, the link between the fire environment and valid fire dynamics lessons are not well understood and inconsistently applied. These limitations may introduce misleading lessons that that can be applied on the fireground. UL FSRI is continuing to study the impact of fuel choice on thermal and chemical exposure risk in training scenarios and develop a better understanding of how this risk may be controlled. This class will provide a first look at those results and an opportunity for fire instructors to discuss implications of these findings.