Fires and explosions account for a large number of property crimes but also may be the cause of serious bodily injury and death. In addition to the requisite expertise needed in many other areas of crime scene investigations, fire scene and bomb scene investigators require added skills to properly investigate these types of crimes. This chapter covers some of the basic information, but it should always be kept in mind that when the crime scene investigation unit does not have personnel with the required training and skills, they should call in support from the appropriate specialist unit in their jurisdiction. Arson and explosions are often discussed together, as they both are concerned with the damaging effects of chemical reactions that release large quantities of energy. In contrast, the special skills and knowledge that scene and laboratory investigations require differ between the two. Both share the characteristic that the focus is on the crime, and many investigations will not produce forensic information to identify the criminal. In this chapter, we first deal with arson and then go on to discuss explosives.